REPORTS ON A 1914 HUMBERETTE RESTORATION

[JV Puleo]

There's nothing in the SAE handbook but I as it expecting much as it pre-dates the introduction of torque specs. I think Mike is pretty safe here at 11 lbs. but I wonder if there is room for a thin lock nut on the other side. That would add a further margin of strength and, if the were tightened against the ends of the thru-bolts a further lock.

 

The spec for grade 2 is 8 lbs. and for Grade 5 it's 13 lbs. so at 11 lbs the Stainless is in the middle. I very much doubt that the rivets were as strong as the bolts - they would they had to be dead soft to have worked so I think we are still in the safe range.

Edited July 4, 2019 by JV Puleo (see edit history)

[Mike Macartney]

17 hours ago, JV Puleo said:

If you have a cone clutch in the flywheel it may not be possible to remove much material.

 

With this V-twin engine there are in fact three flywheels. Later I will try and lay the bits out in order and take a photo, when I take them down to the Jaymic 'packing bench' to weigh the rotating parts. Two are flywheels are each side of the conrod and the other is the flywheel that the cone clutch works inside. I was only intending to remove about an 1/8" from each side of the two flywheels that are on either side of the conrod (1/8" off inside and outside  of each of these two flywheels.) I had not intended at this stage to remove any metal from the clutch flywheel.

 

18 hours ago, JV Puleo said:

The clutch probably runs on a bushing...that should be checked and made as perfect as possible. I think that about 90% of the "trouble" people have with cone clutches is that they need to run very true or they'll grab.

 

Thanks for that tip. I will check that later when I have the clutch in bits.

 

18 hours ago, JV Puleo said:

14 hours ago, Spinneyhill said:

in general a course [coarse!] threaded screw grade 2 should be at least 1 dia threaded depth in cast iron.

If you haven't turned cast iron before, it is quite different from steel.

 

I don't think I have turned cast iron before. I do have a length of cast rod that I bought for a job and never used. I'll have a practice on that first.

 

18 hours ago, JV Puleo said:

In 1914 the value of dynamic balancing was understood but the machines that we have today for that had not been invented.

 

I have set up single cylinder motorcycle flywheels and cranks before using two V-blocks and a dial gauge. At least, now I have the big lathe I can set the crank assembly up between centres to check everything is "tickety boo". I can do the static balance myself, I will have to wait for this though, until I know what conrods and pistons I am going to use. I will then decide whether or not to have it dynamically balanced. In the past I have used Alpha Bearings, but they are Wolverhampton way.

 

15 hours ago, Bush Mechanic said:

From this distance it appears that the area you suggested lightening is actually the counterweight. The arrow may be deceiving me, though.

 

I was thinking of taking the sides of the flywheels down to the area where the arrow is pointing at, just to where the counterweight starts.

 

14 hours ago, Spinneyhill said:

A post in Practical Machinist says - "in general a course [coarse!] threaded screw grade 2 should be at least 1 dia threaded depth in cast iron.

 

I nearly have that much thread in the cast iron flywheel. Where the threads are the thickness is 10mm, but as it has a small countersink for the rivet head I estimate the thickness of thread to be 9mm (0.354) 25 thou off 5/16"

 

2 hours ago, JV Puleo said:

I wonder if there is room for a thin lock nut on the other side. That would add a further margin of strength and, if the were tightened against the ends of the thru-bolts a further lock.

 

When I have got the crank bolted together, without Loctite, I will be able check if there is any room for lock nuts. I agree that it would make the joint more sound and less of a worry, it would have been better if there had been more metal to thread in the flywheel. Thank you for looking in the SAE handbook for me.

[Mike Macartney]

Modifying the main shaft flange on the crankshaft.

 

 

After lapping the main shaft flange to the flywheel and threading the holes in the flywheel I thought it wise to deburr the screw holes just in case they were slightly proud.

 

 

I checked the distance there was between the back face of the flange and the flywheel. After the countersunk screws are fitted my calculations worked out that the heads of the screws would be 0.3mm (0.012") below the area that the side of the big end could touch on (that's a bit of luck!).

 

 

The countersunk screw wound fully home into the flywheel showing the small gap. After others posts, about the thread depth in cast iron, I looked to see how far through the threaded part in the flywheel the screws went. As there were a couple of threads still showing I have ordered some screws 1/8" longer. I can machine the extra off if needs be.

 

 

I wanted to drill a couple of clearance holes in flange for the screws to go through. I struggled, thinking about how to do this for some time. I tried using a 7mm drill to line the centre of the hole, but it didn't seem very accurate. In the end I machined a round bar in the lathe with the end turned down to just fit through the existing hole.

 

 

Before completely drilling through I checked that the hole was going to drill central to the existing hole.

 

 

The first hole drilled out to a clearance hole with no problem.

 

 

The problem was I need to drill a slightly larger hole which I did, after I took this photo.

 

 

The diametrically opposite hole proved more of a problem. The drill snagged and caused quite a burr on the other side of the shaft flange, which I had to carefully grind off, with a small ball shaped grindstone in the flexible shaft of the Dremel type tool. Not having much past experience of machining I found this whole operation quite a strain on the old brain and decided to wait until the countersunk arrived until I did anymore. The countersink was meant to arrive yesterday from Chronos tools, I hope it arrives today.

 

 

[JV Puleo]

Good going Mike. I also find the concentration, and tension of doing precision work, especially on original parts, to be exhausting. I often find myself completely knackered at the end of the day when I know I haven't done anything particularly strenuous. One of the features of posting this stuff on the internet is that it makes it look a lot easier than it is. I suspect that Jeff and Cristech will agree with that.

 

I made a 1/2" diameter center with, I think a 60-degree angle in the lathe. I use that in the drill chuck to locate the centers of holes, leaving the vise just a little loose on the table so it can be jiggled around to find the exact center. It's more a matter of feel than measurement. When locating a hole I drilled, I use the drill I used to make the hole to locate the center...again, it's a matter of feel more than anything else.

 

Edit: 60-degree, not 600 degree!

 

 

Edited July 5, 2019 by JV Puleo (see edit history)

[Mike Macartney]

I'm glad to hear I am not the only one! My admiration for the work the engineers did at the beginning of the 20th century is increasing dramatically as I do more and more machining!

 

The countersunk cutters arrived at lunchtime. I tried one on a mild steel bar and it worked fine. When I tried it on the main shaft flange and this is what happened to the cutter and the hole.

 

 

I did use some cutting oil. Have I bought an 82 degree countersinks for wood or has the flange been hardened?

[JV Puleo]

If the flange was hardened you wouldn't have been able to drill it. I suspect the countersink is defective. I've never seen one like that...the ones I use have a single fluke. I have one I've been using for the best part of 40 years.

[Mike Macartney]

Thanks for the tip on leaving the vice loose whilst trying to find the centre of the hole. It worked a treat.

 

 

I also put the vice on spacers do that more of the round part of the shaft was clamped in the chuck jaws. I drilled the rest of the 5/16" diameter clearance holes for the screws

 

I decided to try the 82 degree countersink at a slower speed and on the milling machine in my other workshop rather than the Clarke mill/drill I am using in the photo above.

 

I gathered my bits and pieces together to take up to the other workshop and dropped my digital camera on the concrete floor! The lens cover won't open now when I turn it on. No more photos, for the time being, as I don't have a smart phone, or another digital camera. I know my daughter has bought a new 'all singing,  all dancing, camera with all the 'bells an whistles'. Hopefully I can use her old one?

 

Anyway, she is away at the Goodwood Festival of Speed today, I'll ask her when she gets back. For now I will just have to do my best by describing what I have done.

 

I wanted to make sure all the countersinks lined up with the threaded holes in the cast iron flywheel. I started off by seeing how many of the holes actually lined up perfectly. I used 5/16 UNC socket head cap screws that were 1" long and managed to get 3 out of the 6 in easily. I did not want to force the others in as I did not want to cross thread them. I undid the bolts and removed the shaft and flange from the flywheel and inspected the underside where I had lapped it in against the recess in the flywheel. The holes had burrs on them. A hand 'deburrer' wouldn't do anything at all. I thought I would try a larger diameter drill bit. Normal 'jobber drills' where no good at all because of the length of the main shaft adjacent to the burr. I found a long drill with a Morse taper on the end and decided to try and use that to get rid of the small burr. I loosely clamped the main shaft and flange to the milling machine bed and centred the hole with the clearance drill I had used to previously. Tightened the clamp and removed the drill and drill chuck. I then had to wind the  bed right down to get the Morse tapper dill in the milling head. I wound the bed up again nearly to the burr and started the milling machine. The drill turned like is was like one of those swing rides at the fun fair! Either the drill was bent or the Morse taper was badly worn. I had a think and decided to use the Dremel type tool again with a grinding bit that had a ball end on it, about one and half times the diameter of the hole. It worked and removed the burrs. I then lapped the shaft flange onto the cast iron flywheel again, just to make sure all the burring had gone. I'll leave the rest of the description until tomorrow - it is definitely a lot easier using photos in the text!

[JV Puleo]

I should have mentioned running the countersink slowly. I find that I drill most holes a good deal slower than the recommended speeds. The drills last longer and you have better control. The recommended speeds are predicated on production machining where any time saving feature is a major plus but with this "one off", highly specialized machining of old parts, where we usually don't know what the metal is, running everything in slow motion works better for me. In the end, the setup and the fixtures take far more time than the actual machining so working at the maximum speed is a very minor point.

 

The fact that tiny burrs prevented the screws going it is a very good sign that you've done a really precise job.

 

You might try getting sets of letter and number drills - all the sizes that aren't readily conventional but come in really handy when you want to drill a hole that is only .010 bigger.

Edited July 6, 2019 by JV Puleo (see edit history)

[Mike Macartney]

22 hours ago, JV Puleo said:

I should have mentioned running the countersink slowly. I find that I drill most holes a good deal slower than the recommended speeds.

 

After having problems with the first try, with the countersink drills, I looked up the problems with cutting countersinks, on the web, and found out about running them slowly. After doing the 6 countersinks for the screws, they are now pretty blunt. I have ordered a set of Irving ones from the states, I hope they will work better on the other half of the crankshaft assembly.

 

22 hours ago, JV Puleo said:

You might try getting sets of letter and number drills

 

Thanks for that, I actually bought a set of number and letter drills when I first retired. I also have metric drills in 0.1mm increments up to 10mm and then in 0.5 increments up to 13mm. My larger set of imperial jobber drills with 1/2" shanks are getting a bit knackered and I could really do with a new set of those. I don't seem to be very good at sharpening drills! As they say about middle aged 'born again cyclists'. I am a bit like them 'All the gear - no idea!' 

 

Found Fay's old camera in her office, so I managed to take some more photos today, while I finished working on the rear half of the crank assembly. I'll put flywheel and main shaft it in the lathe tomorrow, to see if there is any improvement with the runout. I also sorted out my lathe cutting tools and found a few that look suitable for cast iron.

 

Here's a couple of photos taken with the replacement camera.

 

 

Fixing clamps loosened of and roughly lining up the hole with a 6.9mm drill, by moving the mill table.

 

 

Moved the quill of the mill head down into the threaded hole to line it up and then tightened the clamp bolts, before raising the quill and removing the drill bit.

 

 

[JV Puleo]

That all looks very good.

Sharpening drills is a headache. I have a "hobbiest" drill sharpener which seems to work reasonably well on smaller sizes. Very small drill are so cheap I just buy new ones and the big drills, if they start out sharp and you use them carefully, don't need to be sharpened all that often. We have a local drill sharpening service but when I compared the prices it was no more inexpensive than buying them on ebay if you look carefully and don't pay "new" prices. There is a lot of NOS industrial equipment in odd sizes available cheap simply because it isn't used that much in industry any more and it is too big for the average hobbiest. Morse taper drills are like that - if it has a #3 MT shank, you have to have a lathe or drilll press that can use it.

[Mike Macartney]

21 hours ago, JV Puleo said:

Sharpening drills is a headache. I have a "hobbiest" drill sharpener which seems to work reasonably well on smaller sizes

 

I also have a drill sharpener I bought ages ago and just don't seem to get it to work properly. It all seems very 'plastic'. I have another drill sharpening tool that came with the surface grinder and diamond wheel. I will have try and see if I can find instructions for it on the web, as no instructions came with it. I too, buy new drills, for the small sizes.

 

The jobber drills, I have had since I retired, I 'abused them' when making stainless steel parts for my veteran and vintage motorbike restorations. I learnt the hard way; that if the stainless doesn't cut when you first start drilling, it hardens and you then have a nice bit of stainless steel scrap!

 

Since I have owned the big lathe I have never removed the 3-jar chuck. It looks a bit heavy for me. I do also have a 4-jaw chuck, but it is too heavy for me to even pick up off the bench it sits on!  Do you think the part, that the chuck mounts on, would have a Morse taper that I could use to fit a collect chuck in?

[JV Puleo]

The spindle almost certainly has a Morse taper. The only spindles I've seen that don't are on machines that are MUCH older - say before 1900. To use collets you'd need an adapter to fit the taper and a draw bar or you could, perhaps use ER collets with a MT shank on the collet holder. The only drawback there is that you are limited as to how large a piece you can fit through the hole in the lathe spindle. Were I starting out to assemble a collet set, I'd look for an adapter for 5C collets since they are cheap, readily available and made in just about every imaginable configuration including hex and square. Chances are, the spindle is a 4 or 5 MT. I'm using an adapter made for an import Chinese lathe that is 5 MT. I had to make a special draw bar to go with it. It was fairly expensive but since the collets are cheap well worth the expense. I also have the original adaptor for my lathe but it was abused in the past and doesn't run as true as the new one although since the collets have more "spring" than the 5Cs I do use it occasionally.

 

I had exactly the same problem with drilling pin holes in SS valve stems. Since I only had a few to do, I bought several cobalt drills and if they wear out I can just use another but I generally stay away from machining stainless if I can. I've seen old, professional drill sharpening equipment but never had a chance to buy it. The last machine I saw belonged to an older machinist who really valued it.

 

I made the backing plate for the small 4-jaw you see in many of my pictures because I really hate mounting my big 4-jaw. It weighs just over 75 lbs. and is a bear to put on and take off, so much so that I almost always schedule the work so I can do it first thing in the morning. Making a backing plate is a big job but it was well worth doing because the smaller 4-jaw can handle about 95% of my work and it's easy to put on and off. Post a picture of your big chuck... it may be that the backing plate can be turned down and fit to a smaller chuck. That isn't the best solution but if you can't use it as it is, you might as well get something you can use. The 4-jaw is so superior to a 3-jaw that once you get used to using it you'll almost never want to use the 3. The only job I've ever needed a 3-jaw for was holding hex stock that was bigger than the largest collet I have.

 

 

Edited July 8, 2019 by JV Puleo (see edit history)

[Mike Macartney]

Thanks for the information on the collets. I certainly have lot to learn about machining. I looked up collets and mandrels and found a video about a couple of the different types. I do have a set of collets for the Myford lathe, but as yet have never attempted using them. I will go and have a look at them, from memory I think they are of the 5C type. I found this UK site that sells 5C collets and mandrels.

https://www.arceurotrade.co.uk/Catalogue/Collets/5C-Collets

". . .  or you could, perhaps use ER collets with a MT shank on the collet holder."

I also have some E32 collets, I think, they have a holder with a straight shank, they came with the lathe and mill when I bought them. They had some surface rust on them but I have cleaned them up.

A lot of learning for me to do! The problem I have is, that I find it difficult to learn stuff, if I have no need, at the time, to learn it. I prefer to have a job to do where I need to learn how to do something. I don't like making things just for the sake of it - if that makes sense. I am finding it difficult to understand the all the different types of adapters to fit in the machines, especially the Archdale milling machine.

"I really hate mounting my big 4-jaw. It weighs just over 75 lbs. and is a bear to put on and take off, so much so that I almost always schedule the work so I can do it first thing in the morning."

I think at that weight, and my limited breathing capabilities, it would never get used!

"The 4-jaw is so superior to a 3-jaw that once you get used to using it you'll almost never want to use the 3."

I have used the 4-jar chuck on the Myford lathe quite a few times since I bought my first Myford lathe, when I started restoring vintage motorcycles, after I retired, and found I had to 'make stuff', rather than being able to buy it off the shelf. The motorcycles I bought were mainly unusual machines, Sunbeam, Humber, Abingdon King Dick, AKD and Gamage. No 'off the shelf parts' were available for any of these motorcycles. I still tend to use the 3-jaw chuck more, as it takes me a long time to get the material lined up in the 4-jar.chuck. I have used it mainly when I have needed to machine off centre. Next time I use the Myford I'll give the 4-jar another try.

 

I'll try and remember to take some photos of the collets I have and the BIG 4-jar chuck.

[Mike Macartney]

Sorry for all the questions. I do really appreciate the help you are giving me.

 

Photos of the 4-jaw chuck for the big lathe.

 

 

It's not as big and heavy as I thought it was! I managed to lift it and turn it over all by myself.

 

Here is the rear view.

 

 

COLLETS I HAVE

 

This is the set I have that are with the Myford Super 7 lathe

 

 

The stub part is a No 2 Morse taper.

 

 

Sorry about the photo, I am still getting used to Fay's old camera. The Morse taper has a fine thread down the end of the Morse taper,  is that to 'pull it tight' or to screw in a rod from the headstock end of the lathe to knock it out? Or, both?

 

These are other collets that I have got down with the Myford in the bottom shed.

 

 

 

I don't know what the threaded ring is for because it does not fit the headstock?

 

I will have to post the photos of the collets that came with the lathe and mill later as the site won't let me download anymore photos.

 

 

 

[Mike Macartney]

photo of the collets that came with the lathe and mill

 

 

Are these called ER32 collets?

 

PART THAT FITS INTO THE QUILL OF THE ARCHDALE MILLING MACHINE

 

 

I am trying to find out what type this would be. So that I can buy a better one to fit a drill chuck in, the one I have was very rusty inside. The one in the photo is the one that the threaded milling cutters fit into (Clarkson Autolock).

 

 

This part is 4" long.

 

 

These are the dimensions of the diameters. I have not checked the thread yet but it looks like BSW.

[alsfarms]

Hello Mike,  I have been dealing with some significant health issues of my 93 year old mother and simply have not been able to keep up with the automobile chats.  I have just a few moments so I thought I would compliment you on the good variety of machine tools you have.  The quick change pieces make milling machine work more pleasant for sure.  I also agree that the 4 jaw chucks are much more able to repeat a very close center, (as good as the operator makes it and has the skill set).  A three jaw is OK if you are just doing a one off fix and do not need to keep a dead on center for several processes, as in Joe's project.  My 9" South Bend lathe I tend to keep the 3 jaw chuck in it for quick and easy projects.  My 16" Lodge and Shipley, I leave in the 4 jaw chuck.  Yes, I do simply plan to take a few extra moments to center up the work piece every time, but I have grown accustom to the extra time and certainly do like the end results.  Keep up the good work Mike.  Do you have a resolution to your connecting rod issue?

Al

[Spinneyhill]

3 hours ago, Mike Macartney said:

I am trying to find out what type this would be.

Measure the length of the taper and the change in taper then look it up.

 

The thread inside the end is for a drawbar to pull the collet holder into the head or quill. This keeps it stable and stops it turning in the fitting.

 

I have a set of ER25 collets for the ML7 - it has MT2 on the holder.

 

ER25 the range is 1mm to 16mm
ER32 the range is 2mm to 20mm

Edited July 9, 2019 by Spinneyhill (see edit history)

[JV Puleo]

That's a NMTB taper - "National Machine Trade Board"  – probably a number 40. My mill uses #50. If you google NMTB tapers you'll get the dimensions. Those were agreed by a committee representing most, if not all the major machine manufacturers in the mid to late 1930s in an effort to replace the many proprietary tapers in use up to that time. You should be able to find all sorts of NMTB taper tooling...

[Mike Macartney]

Al, Spinneyhill and Joe,

 

Many thanks for the information. Finding out what words or phrases to search on the internet is half the battle to understanding the engineering terms that I never learnt about when I did my OND and HND engineering courses, all those years ago. After finding the info and watching some videos on collets and the various taper milling machine tooling available I am slowly learning. It's like trying to learn another language. I really appreciate the help you have been giving me. Living in a rural community you don't tend to meet many machinists locally who can help you.

[Mike Macartney]

Back to replacing the rivets in the crankshaft with screws.

 

 

In the set of countersinks, I first bought, were 3-sizes. After knackering the large one first, by running it in the drill press. I started with the small one.

 

 

Then the middle size one.

 

 .

 

. . . . and finally the large knackered one which I hoped would still work.

 

If the countersink screws would then screw in easily I fitted them. If not, I tried the socket headed cap screw, as it was easier to get started than the countersunk screws. I was concerned that if I tried to force the countersunk screw I might cross thread it and mess up the thread in the cast iron.

 

 

The countersunk screws were tightened loosely, if that makes sense.

 

 

There were a couple of countersunk holes that the countersunk screws would not go into. I tried putting a taper tap through from the countersunk side and that would not start easily. Again, I did not want to force it, so I removed the clamps and turned the flywheel over and put the tap in from the other side.

 

 

I started trying to turn the taper tap with a small BA spanner when I remembered that I had a set of 3/8" drive sockets that held the square end of taps. I bought these when I rebuilt the MGB to hold taps to clean out the paint from the threaded holes in painted bodyshell. The next bit may amuse you. I spent a good quarter of an hour searching through all the draws in my tool cabinets and couldn't find them. Stood up, scratched my head and wondering where the hell they were. . . .

 

 

. . . . and there they were on my 3/8 drive socket board!

 

I ran the tap through from the shaft end of the flywheel then put the flywheel back on the mill bed. . . .

 

 

. . . . put the tap through from the countersunk side.

 

 

All the countersunk screws now fitted easily but a couple needed slightly more countersinking. I thought I would put off doing this until the new countersink drill set arrived from the states.

 

 

I then mounted the flywheel and shaft in the lathe, between centres, to check the run out. The plank of wood and the two wooden wedges were to help me raise the heavy flywheel to the correct height. I was hoping that it would be better or less runout than before I started replacing the rivets.

[Spinneyhill]

You rotten dog, making us wait!

[Mike Macartney]

Sorry to keep you in 'suspenders'!

 

[Mike Macartney]

I am not sure if I am trying to be too accurate with the measurements on this early flywheel arrangement?

 

Perhaps you can let me know what you think?

 

With the flywheel mounted between rotating centres in both the headstock and tailstock, I set my dial gauge to zero on the 'lowest' part of the flywheel, marked the position and wrote on the flywheel + or - O with a pink marker.

 

 

I then rotated the flywheel to find the highest + reading.

 

 

I then found that this was 0.036" nearer to the tailstock end. I must admit I was expecting it to be nearer 0.000. I locked the lathe carriage, in case that had moved, and tried again, but I still got the same reading. I checked the screws to check that they were all same tightness. I noticed that a couple of the countersunk screws were more proud than the others and that the countersink drill being worn had raised the metal around these screws.

 

 

I then took off the flanged main shaft from the flywheel, set it up in the lathe and machined the burrs off.

 

 

I then assembled the bits together again and this time mounted the flywheel and shaft in the chuck and checked again. This time marking on the flywheel in yellow marker. The reason I changed from between centres to 'in the chuck' was because there were hammer marks on the threaded end of the main shaft around where the original centre drill position was and I wondered if that was why the flywheel was running out of true? In fact it made the results slightly worse.

 

As it is the big end journal that needs to be perfectly in line with the main shaft I decided to check the original machined area around this.

 

 

 

This just shows how the dial gauge was positioned.

 

 

These are the results I got. See the minimum Zero positions and the maximum +0.005" positions. Am I worrying unduly, or should I be concerned?

 

I have been thinking of ways to correct the runout and have come up with three possible ways.

 

1. Do I give the flywheel a whack with the big copper/hide mallet?

 

 

2.  Scribe a line about 0.004" deep where the maximum 0.005" positions are and use a block and fine emery cloth to try and get rid of the runout. I could then see by getting down to the scriber mark that I was nearly there. I could make the low points with blue so I can see where not to rub.

 

 

3a. The easiest would be to turn the material off in the lathe, BUT the counterweight is in the way!

 

 

3b. Shall I set the flywheel up in the milling machine to machine off the 0.005" off?

 

Or do you have a better idea?

 

Before I left the workshop I had a look at the other half of the crankshaft assembly.

 

 

What has happened here or is this is what it was like originally?

 

Your truly

 

a very confused Mike!

 

 

 

 

 

[JV Puleo]

DO NOT hit it with a hammer - though I think you're just kidding there.

 

I was expecting about .020 runout so I don't think you are far off. Do we have any idea how straight it was to begin with? With the rivets loose you could have been getting a false reading... a few thousandths isn't much. I didn't think of this before but did you put the flange back in so the exact same holes lined up? Probably the flywheels were faced off after the flange was riveted in place in order to make them true with the shaft. I don't think they would have been able to work to a tolerance so close that it could have been done any other way. So... I would take a very light facing cut on the flywheels to true them up after the bolts are securely set in place. Given the way it works, I don't think the .005 runout is critical but, looking at that picture you could start at the middle and take a light facing cut out to past the boss for the crank pin. You would just get very fine machining marks that are not concentric with the center of the hole but the face would be perpendicular to the shaft. Is there enough material to face off the heads of the bolts as well? I suspect there is but it would be hairy because you'd have to run at cast iron speeds and I don't know how the SS would cut. It may come out very rough but that could be smoothed after the fact by lapping.

 

Do not try to mill it.... it will come out worse than it is.

[Mike Macartney]

Thanks for coming back to me so quickly. I will read your message a couple of times, and inwardly digest, before I do anything else. What did you think about the state of the other flywheel face? I was surprised it was so different.

 

BIG HAMMER - No, I wasn't joking - remember I was a bodywork man! We like big hammers for straightening things out!

[Roger Zimmermann]

Translated in the metric system, it's about 0.12mm "wobble" . I'm wondering how precise those assemblies were when new. Anyway, I appreciate all the work you are doing on that machine.

[Mike Macartney]

Yes, it has me wondering if it was that accurate to begin with. The flywheel diameter is 270mm diameter (nearly 11"). These are the problems you are up against when somebody has been there before. I did check the runout before I started work on replacing the rivets with screws. I know I wrote the amounts of runout on the flywheel in a chalk marker pen. These marks got washed off when I cleaned everything up. I have just checked in my note book. Lots of dimensions but I forgot to make a note of the runout!

[JV Puleo]

Roger makes a very good point. It is quite possible that it ran out even more when originally assembled although I think they would have faced it to eliminate that. But, unless it went back together exactly as it came apart it cannot be absolutely true. Also, I would not trust your chuck to center the part in order to check the runout on the diameter. All 3-jaw chucks are out a little. It would be better to do that by putting it on centers...one in the headstock and the other in the tail stock. Even that probably has a slight taper but it will be inconsequential to the OD of the fly wheel because the width is so small.

[JV Puleo]

As to that last picture, it looks as if the surface was relieved with a big face mill. Whether that was done originally or is something someone did to fit a different connecting rod is anyone's guess.

[alsfarms]

Hello Mike,

Looks like you are having fun improving the Humberette engine.   I actually doubt that the original engines were dead on.  .005 is close.  For our times and seasons, this is your opportunity to make the engine as good as we can to our 2019 standards.  Like Joe, I would take a "kiss" cut to remove the .005 from the face of the flywheel.  Also, I do not think I would attempt the face off  your  your bolt up hardware at the same time.  I am sure you would end up with some uncontrollable chatter that your cutting tool simply could not tolerate.  I would address the run-out only the face off the bolt heads in another specific operation.

Al

[Mike Macartney]

I have carefully read all your comments and ideas and thought about them for the last couple of days.

 

 

Looking at the photo above of the thousands of an inch difference around the hole for the big end journal, which I wanted to be a straight as possible, there is only 0.003" difference from the highest position 'H' in red to the lowest position 'L'. As they would say in Norfolk "Blaast mee bor - that's buuggger all!". I think I can live with that 3-thou difference.

 

 

I cleaned everything up and had another go at checking the run out at the side of the flywheel between two revolving centre's, this time it was down to 0.033"

 

 

I did double check that I had bolted the flange in the correct place. I thought I had, because I realised it would put the valve timing out, if it was in the wrong place, due to the keyway position on the shaft.

 

I didn't get much work done on the car yesterday, as I had a phone call from Paul the coach trimmer to say that he was organizing a Classic Car and Music Festival on Sunday in aid of Kidney Care. His father died a few years ago after the third kidney transplant finally failed. The local BBC television wanted to do a feature on the event and would I bring my MGB V8 over on Thursday morning for the filming. We cleaned the outside of the car before we went, well, Jane did most of the cleaning! Normal filming scenario - one and half hours filming and two minutes on the telly.

 

Here is a photo of some of the cars Paul found locally at very short notice.

 

 

All I got done today was -

 

 

Threaded a bit of hexagon bar to screw the countersunk screws into.

 

 

Machined 6 screws heads

 

 

. . .  and countersunk three holes that needed a bit more countersinking. It's now 5:10pm - where has the day gone!

[JV Puleo]

Nice job! That's a good idea for cutting down the screw heads.

 

 

[Mike Macartney]

It worked well, apart from having to open up the hexagon for the key in the screw head by tapping the hex socket into the burred hole to clear the burr. I was concerned that the socket may get stuck in the screw head and be difficult to remove, but it worked out OK in the end.

 

Next job is to clean all the parts, have a good 'think' to see if I need to disassemble it again, and if not, put some Loctite on the screws and torque them up to 11ft lbs. I can then have a go at machining the cast iron part of the flywheel to true it up.

[JV Puleo]

If the runout is .033 and the flange is back in place exactly where it was, I suspect that it originally had very close to that amount of runout. The lapping cannot have removed more than about .002, if that and it is not likely to have taken more off on one side than the other.

 

It's always a good idea to pause and think abut it before attaching something permanently.

 

 

Edited July 13, 2019 by JV Puleo (see edit history)

[Mike Macartney]

I am sure you are correct Joe. When I took the screws out again, to clean up the parts of any swarf. I tried rotating the shaft and flange in the cast iron flywheel and it was 'sticky', well, that's not the right word really, 'notchy' is probably a better word. So I decided to give the mating surfaces another 'lap'. I presumed the new countersink drill had caused this 'notchyness'. I then realised that the tool I made for lapping in the two parts would not work due to the now countersunk holes. I needed a plan B!

 

 

The shaft was put into the lathe chuck with the flywheel loose on the shaft. I put grinding paste between the two surfaces and held the flywheel against the flange while I rotated the shaft by turning on the lathe, I held the flywheel firmly against the flange. I was able to reverse the rotation of the chuck. When the 'notchyness' had disappeared I cleaned everything up again and fitted it back together.

 

 

I then looked at my torque wrenches. The large one starts at 20ft/lbs and the small one has a maximum of 8ft/lbs! It looks as if I need to try and find a torque wrench that will tighten to 11ft/lbs. I may end up using my digital spring balance, that I bought for adjusting the gearstick pressure on my MGB V8 conversion, if I can't find a suitable torque wrench at a reasonable price. Looking at the photo above, showing both flywheels, before and after, I am pleased with the results of replacing the rivets with screws. Thanks to everybody for there help and suggestions.

[Mike Macartney]

After a lazy day yesterday at the Classic Car and Music Festival in aid of Kidney Care, watching the end of the F1 Grand Prix and the Wimbledon Tennis final, I got started this morning on machining the cast iron flywheel. I set the lathe on a low speed and started machining 0.010" at a time on a low feed rate.

 

 

I could probably taken a deeper cut and had a higher automatic feed rate? Although it was a slow process it gave me time to sort out some of my lathe tools, milling tools and clean up other tooling.

 

 

Not having machined cast iron previously, I was not sure what sort of finish I should get, but it looked OK to me. 

Edited July 15, 2019 by Mike Macartney
photo in wrong place (see edit history)

[Laughing Coyote]

58 minutes ago, Mike Macartney said:

Not having machined cast iron previously, I was not sure what sort of finish I should get, but it looked OK to me. 

Finish looks about right.  It won't be shinny like aluminum. Nice work

[JV Puleo]

That looks to be an excellent finish for cast iron. Slow speed, slow feed is the way to go. Take off the the minimal amount at a time. Working fast is not your friend when playing with the original, and unreplaceable parts.

Edited July 17, 2019 by JV Puleo (see edit history)

[alsfarms]

Hello Mike,

Your cleaning up flywheels look nice.  If you want to remove some of the sharp profile left after from the cutting process, use slow speed and simply use emory cloth under your finger, holding pressure against the machined surface, to smooth up the profile.

Al

[Mike Macartney]

Al, My first cuts were fine, without any emery cloth afterwards. As I machined the other faces the tool became blunter and gave not such a good surface finish and so I used emery cloth on those. Thanks for the tip.

 

 

I racked my brains how to machine this surface. I tried mounting the flange on the wrong side of the flywheel but that didn't work as it ran well out of true. I then removed the shaft/flange and tried mounting it with the jaws of the chuck through the centre hole.

 

 

I centred it up and managed to get it running only 0.004" out of true.

 

 

It worked but moved a few thou during the machining.

 

 

I decided on this second flywheel and shaft to machine it with the shaft still rivetted in place. I was then able to just machine both sides of the flywheel without removing it from the chuck.

 

 

I then set up to machine the outside diameter to get rid of the worst of the runout on that face.

 

Just as a matter of interest, as I am trying to improve on my machining accuracy, I used a depth gauge mic to measure the depth of the lapped face below the area where the big end sits.

 

 

Below are the results.

 

 

The maximum difference is 0.003". Funnily enough when I put a rotating centre in the chuck, when I went to rotate the flywheel between centres, to check the run out of the flywheel, I moved the chuck round instead of the flywheel and found it changed the runout amounts on the flywheel by 3-thou. Is this likely to be just a coincidence?

 

Once I get the flywheels joined together again and the shafts in line, I was going to machine the faces again. I think I will need to make a jig to hold one shaft in the chuck, while the other end is held with a rotating centre. I will have to think about this. I am enjoying the learning experience, but am surprised at the amount of time this flywheel assembly is taking.