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My 1910 Mitchell "parts car" project


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10 hours ago, JV Puleo said:

You can see how far it hangs over the front and the need for the plates to support it.

 

It's a shame nobody has invented 'sky hooks'.

 

I think I have probably missed something? When you drilled the top of the new cap how did you know the drilling position to match up with the hole you had milled in the block?

 

Silly me! I have just realised, of course the part hasn't moved because it is clamped to the milling table and the cutter and drill positions are the same. I apologise for me being thick.

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Well, that doesn't seem like an odd question - especially as I had to keep stopping to remember the order the operations was done it. The hole in the cap had to be drilled before the hole in the crankcase was threaded...

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Today I put the threaded sleeves in the mount for the water pump. You can see how off-center they are with each other.

 

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I centered them as best I could. The end mill left a tiny amount of thread on one side of the hole and a similar amount on the opposite side of the other hole. Since the hole is threaded and the insert is permanent, this isn't important. After the first hole was milled, I clamped it up to drill for 5/16 screws.

 

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Then threaded the hole. I bought a new tap for this... I only had one 7/16-20 tap and it is probably about 90 years old.

 

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The result is more than satisfactory.

 

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Here it is with the caps in place. They will be screwed down tight when it's bored.

 

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Then, because it's all set up, I located the hole for the oil filler/return.

 

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I planned to bore this out to .950 and thread it for another brass insert but, as the hole got bigger, I realized that the insert would have to cut into the wall of the casting. I decided to go to 13/16 and thread it 7/8-14 - the actual size of the oil connection...this isn't a part that will be taken out once the engine is assembled so I'm not as concerned about wear or stress on the threads. I will put a little Never-Seeze on the threads so it doesn't stick but since it will be constantly wet with oil from the bottom I don't think that is a concern.

 

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And I tried the oil filler to make sure everything fit.

 

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I thought today would likely be a total loss as I'm waiting for an end mill and some brass rod. I'd planned to make some inserts but the only thing that came in was the end mill. So... I set to work opening up and threading the holes that originally held the oiler in place. Two of these had screws broken off in them and one of those was drastically off center.

 

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For the third hole I had to take the extension plates off and set the crankcase on the table. I also had to work from the back as it was the only way to get the hole under the spindle.

 

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But, it worked ok...

 

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The last step was to put the extension plates back on, turn the crankcase around and to the two holes that are used to attach the exhaust pipe bracket. For this, I moved the center of the holes slightly. I'll still have to make a new bracket but now it will fit better.

 

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The crankcase bolted to my "boring bench", the bed of a lathe that was beyond repairing (and missing its legs)

 

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Since I have to make the boring bar, I needed to figure out just how far the tool has to be from the end to allow it to be withdrawn so I can re-set it. I also fnally figured out how the gearbox advances the boring bar so I'll have to make something for the rack that moves the box to attach to. All these details are incorporated in the machine but I'm only using the gearbox so I've some hard thinking to do to come up with a way to attach everything.

 

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16 hours ago, JV Puleo said:

I also fnally figured out how the gearbox advances the boring bar

 

It would be good if you could share the information with us, when you get a chance. Since you started mentioning about line boring I have been watching some videos on the subject. None of them seem to show how the tool is advanced. To me It seems to be 'witchcraft'.

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In answer to Mike's question, I had to make this piece for the boring bar to pull against.

 

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With that done, I assembled the parts. It seems to work. I'm not thrilled about the weight on the end of that long bar but the only deflection I need to be concerned with would be between the pillow block and the piece I'm boring and I doubt it is deflecting at all.

 

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I will probably turn it by hand, I tested the electric drill and, to my mind, it turns much too fast. I don't need a mirror surface these parts...a very small amount of roughness might actually be good. But, for the main bearings I would like to motorize the bar like edinmass did and for that I'll pose a question since I'm guessing there is someone out there who knows a lot more about electric motors than I do. I need to turn the bar at about 60RPM. The thought came to me to use a gear motor but finding the right one is a challenge. I've no idea how big it would have to be since it will have to develop enough torque to turn the cutting tool against the aluminum casting and the iron bearing caps. Any ideas?

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9 hours ago, JV Puleo said:

I need to turn the bar at about 60RPM

 

They are available. The only problem is finding one at the right price. The one below turns at 56RPM

 

https://uk.rs-online.com/web/p/ac-geared-motors/4784847/

 

Thinking about it. There is a possibility that I may have a spare one for our Klargestor sewage treatment system. It would be 240 volt but I would have thought you could either use a transformer or it may run even slower on 110 volt? I will have a look this morning and see. If I have got one that still works I could send it over to you by airmail.

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DC motors seem to be more available but if possible I'd rather use AC 115 volt since I could just plug it in. I also have a couple of 240 volt plugs so that isn't impossible either although it would involve a long extension. This is one of those problem I'll be thinking about while I do the first two holes...just maybe I'll have come up with a possible solution by the time I'm ready to do it. The motorized boring bar is probably only needed for the final boring of main bearings and I won't be able to do that until I've made shells and Babbitted them so I'm some months from that. There is probably a simple solution, it just takes time to find it.

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Thanks, I'll look into that.

 

I "made" the boring bar today. Most of the bars I'm familiar with use round cutting bits with a flat on one side but I have been unable to find any small enough for this bar - it being only 3/4" thick. so, I decided to use square lathe bits but to do that I need to put a square hole in the bar. I set it up in the mill, .050 off center. This is because the point of the bit must be on the center line of the hole. If I used a 1/4" tool bit, I'd have to grind .125 off one side. By offsetting it, I add .050 to the thickness of the bit at the cutting edge. If I used the 3/8 diameter bits from the original bar I wouldn't have had enough thickness to fit the set screw.

 

First, I milled a flat on the bar to get a flat surface to drill.

 

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Then drilled and reamed to 7/16"

 

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Here's the hole finished.

 

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Then I cut a piece of this square hole sleeve to fit without protruding on either end.

 

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The sleeve in the hole with a 1/4" lathe bit in place.

 

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I put it back in the mill to locate a hole for the set screw...in the center this time rather than offset. Then took it over to the drill press to drill and tap.

 

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The set screw just fits below the surface on the "fat" side of the tool bit.

 

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With that done, I reattached everything to the engine.

 

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I pressed the remainder of the square hole sleeve into a piece of 3/4 square stock to make a fixture for holding the tool bit when grinding.

 

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This also gets a set screw at one end.

 

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Then I ground a tool bit but neglected to take pictures of it... It's the end of the day and I know myself well enough to realize I'll make an error if I push too hard. Tomorrow I ought to find out if all this works.

Edited by JV Puleo (see edit history)
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Joe, how much HP will you need to spin the shaft? I have a DC motor and control that came from a mill building that you could have. I’ll take some pictures of it and post. It’s not really that big and don’t know what HP or stall speed would be but I think it’s worth a look. It even has a clogged pulley and belt with it I believe but have to look at it. I have no use for it and would like to see it go to someone who could find a use. Im pretty sure it’s 120v ac and the controls convert it over to variable speed DC. Seeing since your close and the wife and I enjoy Lindys, my arm could be twisted to drop it off if you want it! 😁 I get some pictures up tomorrow.

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That sounds good to me. I have no idea what the HP should be but a hand-held electric drill will turn it, albeit to fast. I'll be taking light cuts in any case so I suspect 1/4 HP (or maybe even less...the slow speed would greatly increase the torque) would do it. Thanks!

 

jp

Edited by JV Puleo (see edit history)
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32 minutes ago, Spinneyhill said:

Have you thought about the remaining strength of the boring bar where you have taken away more than half its cross sectional area at the bit hole? The bar will become quite a bit more elastic in that area.

 


It won’t be a issue. The bar has almost zero load on it. My bar has a cutter hole in it every six inches or there about. You can actually cut several mains at the same time......if you are good enough. I would never try it. The only reason to do one at a time is not cost.....it’s replacement of the shells if the bearing doesn’t come out correctly. The down time of having only one shell done can be very time consuming. Cutting main bearings is certainly more craftsmanship than one would think, and the learning curve is steep. A nine main bearing crank will deflect a huge amount just from its own mass...........and most are not supported correctly when removed from the crankcase. They will bend under their own weight. It’s interesting to straighten them.......pounding on them with a hammer. After years of experience you learn to handle them carefully and that way you don’t end up with issues. A nine main bearing crank should turn with just the pull of a single finger...........and today most people don’t have the talent to get the crank correct. Seventy percent of the engines in our shop are “do overs” from someone who brought it to the local guy to do it.......after all it’s just an old flat head. Today modern manufacturing and machining make the process much more consistent and less dependent on craftsmanship. Pre war every engine builder was a craftsman. Labor was cheap. Today labor is the most expensive value added cost in manufacturing. 

Edited by edinmass (see edit history)
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On the new rear cap with the single bolts that secure it...........you have quite a bit of extra material there on the new cap......how do you plan to remove all the extra before you go at it with the bar? 

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Maybe... I'm certainly tempted to and probably will...I've only just recently thought of a way to do it uniformly. I regretted not making the hole in the center larger but I made the pattern almost 8 years ago. The patterns for these two pieces were literally the very first things I made - never dreaming it would take this long to get to the point of installing them. At the time I made them there was no way I could have done the job. I'd only just got the lathe back together and working after sitting outside for 15 years.

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1 hour ago, JustDave said:

Joe I’m just asking not second guessing you’ve probably forgot more than I’ll ever know,can you use needle rollers in the main bearing shells instead of Babbitt and in the rods,   Dave

 

 

The answer is a simple no............there is nothing wrong with babbitt, and properly done and serviced will last 100 years, or more. Modern oils help more than one can imagine.

 

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There are a host of reasons why that would be unlikely to work, not the least of which is that the rollers and the crank have to be of nearly identical hardness or one will gouge the other. I am going to make bronze shells so that the thrust ends will be bronze and not Babbitt. Mitchell poured the Babbit very thick into the aluminum crankcase and, because it doesn't stick, put holes in the seats to keep the Babbitt in place. I don't think they line bored the case prior to pouring the Babbitt - it's so thick that even casting irregularities wouldn't have mattered. This was a poorly made engine. The design is conventional so there is nothing basically wrong with that but in workmanship they took every available shortcut. Still, the car is 109 years old and the bearings are still intact so it served their purposes.

 

Another consideration is that these brass car cranks are a lot more flexible than modern cranks. If those 9-main-bearing Pierce cranks that ed works on flex, this one must be a rubber band. It does have generous main bearing journals (2" diameter). I have thought about using inserts on the rods...the length is so short that I don't think flex is a problem but they are splash lubricated and I suspect Babbitt is better for that. Since I'm going to make the rods, that decision is still a long way out.

Edited by JV Puleo (see edit history)
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Today was the moment of truth...finding out if all this will work,

The first thing I discovered was that the hole in the bottom of the micrometer device was too small because I'd forgotten to take the offset into consideration so I enlarged it.

 

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I set it to take cuts of .025 with the "rough" finish feed rate.

 

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This is how it works... the depth is set then it is clamped on to the bar and the tool pushed forward until the tip touches the anvil. This is a bit imprecise. The big boring bar has blind holes with springs in them so that the tip of the bit presses against the anvil but there simply isn't room for that here.

 

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It cut quite smoothly. For this job I would have been satisfied with the rough finish.

 

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I went with .025 until I got to what would be the last cut. Then I went .015 with the finish speed, followed by .010. This is the final cut.

 

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And the result. You can see the anchor holes for the original Babbitt in the bottom half. A quick measurement shoes the hole to be about .002 undersize. I can live with that...oversize would be worse as I am not going to make a bronze bushing to fit this hole and I want it to "pinch" when the cap is screwed down. I'll make the bushing and then bore the hole for the water pump using that as the anchor for the front end of the boring bar. That way they have to be in perfect alingment.

 

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Joe, here are a couple pictures of the motor and control box. It runs well and speed control works properly. The data plate is hard to read but I’m pretty sure it’s only a 1/15 HP, 3450 rpm motor. It does seem to have a ton of torque. Motor is about 4.5 in diameter and is just sitting on top of the control box. It is probably worth trying at least. If you want to try it, let me know.

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It’s yours. I believe you will have to put a decent size pulley on the shaft to slow the final speed down but I’m sure you’re up to figuring that out!😁, It is fuse protected with a old school glass Buss type fuse and the original was popped. I put a 2.5 amp in it to test and when I tried stopping the motor, I got the fuse to pop again. I think it had a 7a slow blow in it. I’ll bring the original fuse with it. PM me your address and contact info and I’ll drop it off in a few days when I’m out that way.

Edited by chistech (see edit history)
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The next step is to bore the large hole for the water pump. In order to make certain it is in perfect alignment with the shaft I made a temporary bushing for the saddle I'd already bored. I will eventually make a bronze bushing for this but to do that there are some critical measurements I need to take. All that is important here is that the hole in the center is concentric with the bored hole.

 

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Then I bored out the top half of the water pump clamp. This is simply to remove material quickly so I don't have to do it with the boring bar. The complication in this was that it took me some time to think of a good way to clamp it down. when the idea did come to me, it was fairly easy to do.

 

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I was not trying for a perfect fit...or, better said, a perfect fit wasn't important since the boring bar will make it perfect. By some quirk of fate it came out much better than I owould have thought possible if I'd been trying.

 

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Yes, that's exactly how it works. Now that I know how it works, it would be possible to make a gearbox like this but it would be a good deal of work. I wasn't happy with the long end of the  wobbling a bit so I've moved one of the aluminum bars used to position the bar down to steady it. so far, everything seems to be working just fine.

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This morning I ground another tool bit and started the big hole.

 

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This is the finished product. It's about .005 oversize and I've decided I need to improve my measuring device. It won't make any difference here, which is why I wanted to do these hole first. I can easily compensate for any irregularity but I need to get the device accurate to .001 to do the cam bearing. I have a few ideas...we'll see how they work. I still have to face these on both sides before I take the setup apart.

 

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This piece will be the split bushing that clamps the water pump to the crankcase.

 

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Reamed out to 2"

 

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It was then turned down to .002 larger than the diameter of the hole in the mount and faced off so that it is about .050 wider than the mount.

 

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Then into the mill to have a slit .100 wide cut.

 

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I'd say it clamps up just about perfectly.

 

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But this was the real test. The 3/4" shaft that runs from the drive gear to the magneto has to be perfectly straight, especially in the space between the two saddles on the case because that is where the timing adjuster will go. It looks as if I've managed to do it.

 

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I notice you can also see how badly corroded the left front arm on the crankcase is. Something will eventually have to be done about that. The hole is also badly worn, as if it was operated with the bolts loose for a long time or as if water was dripping on it. That will probably get one of my threaded brass sleeves.

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I started today by grinding a facing tool and facing off the saddles and caps so their surfaces will be perpendicular to the shaft. This worked reasonably well but I realized that I will have to clamp a piece of 2" bar in the big saddle to keep the split bushing from moving. Because is is slightly springy, it isn't as tght as it would be without the split.

 

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I've had to order some materials to make a tool I designed to finish the small saddle. I don't want to take this apart until all the operations are done. As it is, I run no risk of changing any of the alignments so it's best to take my time and get everything done at once. In the interim, I cut a piece of bearing bronze to make the bearing that will go in the small saddle.

 

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And then thought of a couple of reasons why I want to finish the saddle and cap before I machine this. So, I decided to make the threaded sleeves I need for the crankcase.

This is threading the outside 1/2-20.

 

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The last step is to thread the inside 5/16-18. Because I had more room here, these inserts have a thicker wall than those I made for the saddles. The job also went more quickly. It

s amazing how having done something, it's so much easier the second time around.

 

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The inserts... I made an extra to put in my "inserts" box against future need.

 

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I inserted all five using a little high strength Locktite on them. In period, they would have staked them but I hate hammering on old castings.

These are the two that will hold the exhaust pipe support bracket.

 

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Joe, I am curious, with all of the work you accomplish in one day, do you set a limit on the time you spend in your shop or do you do like most of us do and go until you drop?  I find it hard to quit when I have a good rythym going with minimal intervening math issues!

Al

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