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My 1910 Mitchell "parts car" project


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These two pieces of aluminum are going to be the center mount for the boring bar.

 

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Cutting slots for the bar and the bolts to pass through.

 

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Then clamped together to be drilled and tapped.

 

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The finished piece...

 

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Mounted on the engine. I pressed the bar against the ground gauge I made to make certain the center of the shaft was at the correct height.

 

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The bar will be driven with an electric drill but to control the feed I have this from my Ammco Boring Bar. Until today I didn't know how it worked and it appears that the adaptors I'll have to make are very simple. As you can see, it had a hard life so I'm going to replace the center shaft first.

 

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This is the sort of thing you often have to deal with when working with old, 2nd hand machine tools. Not everyone was careful with them.

 

 

Edited by JV Puleo (see edit history)
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I think so... the bar is held on both ends and I will only be boring aluminum. The length of the bar between the bearings is only about 9 inches so I don't think it will deflect. The actual size of the holes isn't critical in this case but I want to test everything before I do the cam shaft... Actually, the camshaft is probably a bigger problem because the bearings will have to be about 24" apart. I may well have to take very small cuts but, in that case I will be making a seat that a bronze split bearing will be pressed against.

Edited by JV Puleo (see edit history)
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Joe, Do you use a smart phone?  If you do it likely has the provision for short video clips.  I am rather "slow" with my smart phone but stumbled on that feature on my phone.  I am surprised, I can actually take good video clips, with sound and post them just like a picture.  If you can do a clip, it would be fascinating to see your boring bar run and go through the motion of cutting an ID surface.  As mentioned, before, it generally takes way more time building the fixture than actually making the cut.  You will end up with a tool that could be modified to work on another application, (if needed).  My, isn't the machine/tool building process rewarding!

Al

Edited by alsfarms
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No. I make very few phone calls and of those I get about 90% are robo calls. I do have a flip phone but  often forget to charge the battery and hardly notice it when I don't get a call for a day or two.

I think I am a lot ore relaxed about making the tooling than I am about the job itself. Working on the original parts always involves a certain amount of tension where making something I can scrap and start over is much less taxing.

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Joe,

All I can say is AMEN.

I do use the dang cell phone as I have to for business reasons and of course my family would have a "come apart" if I were to get rid of my phone. (I would like to)

Yes, messing around getting is creative and yet rewarding.  However, when you get on a piece that would be very hard and costly to replace, the tension does ramp up significantly.  Very rewarding when a rare piece that was worn out finds new life.....REWARDING!

Al

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Today I took the boring bar gear box apart to fix and what should have been an easy job still took most of the day. I started by putting a slot for a Woodruff key in the center.

 

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The challenge is that the selector inside the gearbox slides on this shaft. The key keeps the gear from rotating. But, since it's a sliding gear it needs a little clearance and the slot has to be perfectly placed and parallel to the shaft. The shaft was held in a collet block in the vise and it didn't work. After about two hours trying to get the gear to slide easily on the key I came to the conclusion that the keyway was very slightly crooked. If you were pressing a gear onto a shaft you'd never notice but in this case it kept it from working. So, I turned the shaft 180 degrees and did a second slot. This time with the collet block clamped to the mill table.

 

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This one was a lot better although I only got it to slide easily by using a little grinding paste and moving the gear back and forth over the key until the burrs (which were probably microscopic) were smoothed out.

 

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Then I milled flats on both ends for the set screws. I'll use soft point screws too. I don't like marking the pieces up and the difference in price when you only use a dozen or more a year, is inconsequential.

 

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I also made a sleeve that will adopt this to the small boring bar and another one that will mount the handle used to turn the bar for facing. One of the problems I had in understanding this was that it appears that at least one piece of the machine is missing and judging from the hard usage it's had, I suspect its been missing a long time. I'll need this machine for the main bearings so I might as well fix everything I can while I have the box open.

 

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I don't actually have the manual for this but I do have one from a very similar model. It includes the price list for replacement parts. This little gear box cost $75.00 in 1957. About 30 years ago I had one of these machines that had never been unpacked - everything was new and the address label to the shop that bought it was still nailed to the cover. I paid $100 for it from the racing car machinist who did some of my work in those days. I never used it and when I closed my garage I advertised it in Hemmings and sold before I even saw the ad for $1200. I was pretty happy with that but I wish I had it now.

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There isn't much. I spent a lot of time looking because I thought I'd have to build one. I even designed a gearbox. This one came up for sale while I was in England and a friend was able to contact the seller and make a deal for me. Fortunately, he was not in a hurry and content to wait until I got back. He even delivered it... although he was in Connecticut, he had worked in Woonsocket (where the shop is) some years earlier and had actually lived just down the street from the shop.

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I drilled and tapped the adapters that will attach the gear box to the boring bar and to an electric drill.

 

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The one on the left goes to the boring bar. The one on the right still has to be fitted with an extension that a 1/2" drill can attach to. The original part in this set was missing which may explain why the shaft in the gearbox was so badly chewed up.

 

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I decided to do this with 3/8 hex stock - which I happen to have - so I made an insert and broached it to receive the hex.

 

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Then drilled and reamed and used on of the 1/4" dowel pins I bought when I was making the oil pump.

 

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I may have made a small mistake here in that I think the original extension was much longer so the hand crank will clear the box when in use (there is a rack that fits in the square hole and it is long enough so that the hand crank must stand back from the rear of the box). It won't make a difference to a drill but it may make a difference when facing the bearings which is supposed to be done by turning the bar by hand. With that in mind I decided to make the extension out of aluminum (to save weight) and use brass inserts on either end ... on the female end to receive the hex stock and on the hand crank end to test my threaded inserts.

 

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Edited by JV Puleo (see edit history)
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Here's the insert with the hex hole broached.

 

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I also counterbored the back end so the broach only had to cut the area where the hex bar will go in.

 

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I then reamed a 7/8 hole about 2-1/2" deep in one end and drilled the other end for a 3/8-24 thread.

 

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The end with the insert was drilled and reamed for a dowel pin and the threaded sleeve screwed into the other end with a drop of Locktite on the threads.

 

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The gearbox with the handle attached.

 

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These are the 3 pieces I made. I have to get more soft point set screws but this part of the job is done. When I opened the box the machine is stored in I found the missing piece but I think mine are a bit better.

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While I was working on these parts yesterday it came to me that I'd made a mistake in the measurements for the micrometer boring bar adjuster. I'd forgotten that the hole for the water pump is a lot larger than the hole for the shaft and the way I'd made the adjuster it wouldn't travel far enough to do the water pump or the camshaft bearing. After thinking about it quite a bit I made this extension.

 

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I had to open the hole in the top of the adjuster up to 1/2".

 

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But it went together quite well. I doubt you can see it here but this is the adjuster with the mic set a zero and touching the bar. To get the cutting tool diameter I will use the mic and add .375 - half the diameter of the bar. If it works, that should get me within .001 of the desired diameters.

 

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I also dropped off an 11/32 end mill with the tool grinding shop to be ground to the hole diameter for a 3/8-24 thread. I want to use that to make the holes for the smaller threaded sleeves as the original holes look as if they were drilled freehand and when I set it up in the mill I can correct that.

Edited by JV Puleo (see edit history)
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Looks like a Kwik way bar kit cutting tool measuring device..................👍

 

Here is our pre war Quickway bar set up........made to be hand driven, but we set it up for a machine drive......much better results than by hand. Pierce V-12 block in photo.

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Edited by edinmass (see edit history)
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In order to put the crankcase in the mill to drill the holes for the threaded sleeves I have to reorient it to face in. For that I took the torsion plates off and squared the ends. It's arranged in the mill so that the plates are bolted directly to the table with the end over one of the T slots so I don't hit the table.

 

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The ends squared off...

 

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Then I have to slot the front hole for long bolts that will hold it down to the bable.

 

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I only went through the top plate since I only need one slot. It marked the plate under it slightly but that is inconsequential.

 

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Then rebolted both plates to the crankcase lining them up on the holes for the lifters. This probably isn't perfect but it is as close as I can reasonably ger.

 

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The squared end will give me a surface I can indicate when I put this back in the mill.

 

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I also need 2 pieces of steel 29" long and 4" wide. All I have is this piece which is the correct length but 8" wide.

 

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So I pulled the vertical head and set the machine up as a horizontal mill. When I finally get my vertical mill back together I will leave this one horizontal. Horizontal milling has a lot of advantages but it's something of a pain to switch it over... though that may be because I do it so little. You can see how the head is supported by the crane. It weighs something like 300 lbs so soing this without the crane would be a real issue.

 

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With the machine in horizontal mode, I set the piece up to cut with an 8" slitting saw. The aluminum angle clamped to the table is there to give me a surface to measure against. It is also set up so that the saw descends into a T slot.

 

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I got a little more than half way through before my back started hurting from all the standing. I'll finish this tomorrow and switch the machine back to vertical.

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Joe, yet again I am blown away by your work and attention to detail. I have a few questions that are better shown with one of your photos on which I have added some numbers.

 

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1. Does the vertical head stay on the crane and just swing out of the way when not in use?

 

2. Is this an oil filter system you have fitted to the mill?

 

3. What is this long stainless steel or aluminium bar for that appears to be clamped to the table?

 

4. (not in this photo) Is that ordinary paper that you have stuck to the torsion plates for marking out for machining?

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The head unbolts and pulls out, hanging on the crane. It's unbolted in the 2nd picture above but I should have swung it around to the side for the photo. I'll take another today.

 

The mill had an internal cartridge oil filter that is long obsolete - it was missing too. I made that setup to replace it. The lines connect to the original oil lines inside the mill.

 

As christec has said – the aluminum angle is just to measure against.

 

I glued the paper drilling template to the plate and just didn't remove it. It came in handy when I had to measure and mark additional holes.

Edited by JV Puleo (see edit history)
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I had a bit of a problem first thing this morning... I'll post some pictures later but I apparently took too deep a cut and the saw gouged the key. When I tried to take it off I had to rap the blade with a plastic hammer and cracked it. I am almost all the way through but don't want to disturb the setup. So...I went to ebay to see if I could find a replacement saw and found two, in North Chelmsford Mass for about $35.00. I ordered those and some key stock from McMaster Carr. If I am lucky, I could have the stuff by the weekend but I'm not holding my breath. Now I'll have to find something to keep busy with until that comes in.

 

I have very little experience with slitting saws. This is only the 2nd time I've tried to cut steel. It appears that their use is counterintuitive. They run very slow and you have to be careful not to take too deep a cut.

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Here is the machine with the vertical head bolted to its holding plate while set up to run horizontal.

 

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And the gouged key. Nothing else was damaged and if I hadn't cracked the saw I could have fixed it and gone on.

 

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You can see how close I was to finishing.

 

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This gave me a chance to think about some other aspects of the job. The setup for drilling and tapping the hold down clamps is so elaborate that I've decided to do the hole for the oil filler and two of the holes for the plate I'm thinking of making to hold a generator. The oiler went here. There were three screws, two of which are broken off in the crankcase. All three of these will get brass liners and I'll correct, as much as I can, the one that is drastically off center.

 

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Then I busied myself by tidying up the shop a bit and getting a flat surface on underside of the clamps.

 

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This was just sandpaper on the table of the drill press. I found it worked better dry than with a little oil on it. I lapped this piece to see how close the sandpaper technique got it and found that it was very good. The lapping wasn't necessary.

 

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I could but I can find other things to do until the saw blades get here. In the long run, a few days either way doesn't matter much and if I get so other things done that will have to be done sooner or later nothing is lost.

 

The mill was probably made in the late 30s. It has an NMTB taper spindle and I don't think those were introduced until about 1934.

Brown & Sharpe was located in Providence, RI. I drove by the old factory every time I went to work and my late uncle was a long time executive there. It was through his son, my cousin, that I met  Henry & Peggy Sharpe. Henry was the last President of the company - before it closed down it's operations in the 1970s (the name was sold so there are new B&S tools but I believe they are made in Switzerland). Once, about three years ago, I had the current generation of Sharps (who would be about the same age I am) in the shop to see that mill run. They had never seen one in operation. I have a collection of their catalogs going back to 1878 and this one looks closest to the illustration in the 1938 edition.

Edited by JV Puleo (see edit history)
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How right you are. And Morse developed the Morse Tapers. Virtually all lathes use MT tooling (Mikes being an exception!) and, until the advent of the NMTB tapers, practically all milling machines uses B&S tapers. There were others, like Jarno (developed by a B&S man) but between those three you'd cover about 90% of the machine tool trade.

 

Oh... and NMTB is the National Machine Trade Board. It was an association of all the major makers of machine tools, B&S included. They agreed on a uniform taper design so that the tooling would interchange between machines of different makes. The specifications are still in use today. When you see "CAT50" on a CNC tool holder it's the same taper as NMTB 50.

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No real progress on the Mitchell today as I'm still waiting for the slitting saws. I spent the day cleaning up the area of the warehouse basement where I do some woodworking...a job that badly needed doing. This cutter did come in...

 

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I may have to have it reground with a more acute angle but I think this should do the trick. When I made the front hub for the engine and the end of the hand crank that has to mate with it, I could not figure out how the dog teeth were cut. I did think that when I finally figured it out, it would be insanely simple. Well, it is, although it takes a tapered cutter. After the teeth are cut, both pieces should be hardened and, in this case, I was careful to buy a known modern steel so when I take it for heat treating I can say exactly what it is. I'll do an experiment first though, just to make sure I got it right. I'd have done it today but I need the mill back in it's vertical mode.

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Here is a photo of the other end of the Quickway bar........you can see the feed mechanism for the cutter. The bar is driven from the other end. Originally this was a hand driven set up. We found that using the electric motor provides a much better finish.

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The Ammco bar is set up in almost exactly the same manner although I've been told the Kwikway has a better centering system. The instructions I have (which are for a later version) suggest driving it with a 1/2" electric drill and only using the hand wheel for facing the bearings. I'm going to try the electric drill on the first hole - the one for the magneto/water pump shaft. If I think it will help, I'll look into using an electric motor. Do you happen to know what rpm you run it at? I'm thinking it would have to be pretty slow. I might look for a slow DC motor to do it.

 

Even though I had one of these years ago, I never used it and sold it when I closed my garage. David Greenlees suggested I get another - his comment was that if you are patient and careful setting it up it will do an excellent job - that the usual problem with automotive machine shops is that they are in a hurry to get it done fast and not all that careful how they do it. In any case, I don't really have a choice in this. It's a job that is only suitable to someone who has a good grasp of early car work.

Edited by JV Puleo (see edit history)
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You are spot on.....it's VERY time consuming......and most of our cars have 9 main bearings. After years of using it, figure 4 hours set up, and two hours per bearing. When we are finished, you can spin the crank with a pull of your pinky finger. There should be zero drag on a crank, and only the shear of the oil film breaking to get it to turn. We try to hold to the tenth when cutting bearings but usually across the the 9 of them we have a variance of 3 -4 tenths. Not too bad for a 80 year old hand bar. Temperature will affect the bar.......so its best to get the room at an even room temperature for the process...........good measuring tools, sharp cutters, and lots of light and time and they turn out great. Also, only use a very reliable source for pouring the bearings.............lots of issues with new to the game back yard operations.....we have also made shells over the years, and installed shells where there were none before..............very, very time consuming. We make our own cam bearings for all of our engines.....we find most shops just not up to the job. 

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The micrometer that came with my boring bar - which is the original tool, made by Starrett - doesn't measure in 10ths. I have a B&S micrometer head that does so if the device I made to set the cutting tool on the small bar works, I'll make another for the larger bar using the 10ths head. I'm not convinced it's critical to get much closer than .0005 though. There are only 3 bearings and what must be a slightly flexible crank (like nearly all brass car cranks). I'd think a Pierce 12 is a lot less forgiving. That said, it is always worthwhile to try t work to the closest possible tolerance  because if you don't try you'll never do it.

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I should add that I'll have to align bore twice. I plan to make shells as Mitchell used Babbitt in the aluminum crankcase. Since Babbitt doesn't stick to aluminum, they just put holes in the bearing seats to anchor the Babbitt. The original Babbitt is still there but I have no idea if they made any effort to get the holes straight in the first place. Since the Babbitt is about 1/4" thick I'm inclined to think they didn't. So, I'll have to bore it to get the Babbitt out and the holes round and in line, make the shells - which will call for facing the bearing seats since I'll want to include bronze thrusts on the shells, then pouring the bearings and boring it again. I have fixtures to hold the shells, which came with the boring bar, so I'll probably do that myself too.

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I lucked out today. The saws arrived but the office is closed. fortunately, the letter carrier knows we are closed on the weekend so he left the package at the Post Office and I was able to pick it up.

I put the new saw on... (Actualy, its on backwards in this photo. I realized that after I'd taken it and turned it around.)

 

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And finished the cut.

 

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The piece of steel is actually about an inch too long for the travel on the mill but by sinking the saw into the T slot I was able to take advantage of the increased width and just made it without having to move the piece down.

 

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I'll switch the machine back to vertical tomorrow. This is enough for today.

Edited by JV Puleo (see edit history)
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This afternoon I changed the mill back to vertical. The only tough part is lining up the head with the body of the mill. Since it's very heavy, and you can't see the connection when it is close, it's a fiddly job. I've only done it four or five times - I suppose if I did it more often I'd be better at it.

 

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Then I drilled two holes in each of the two 4" plates. I broke off a center drill on the second hole so it took me a lot longer to do this than I'd intended.

 

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This is what I'm aiming for...a way to hold the crankcase steady and flat while positioning it under the spindle.

 

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I also discovered this interesting problem. The oiler had a connection on the outside of the crankcase for the center main bearing. But, the output end of that hole is nowhere near the bearing. In fact, it's in a place where it cant' be reached. The bearing itself has 4 holes but no provision for connecting it to the oiler. This will be an interesting problem to solve if I want to get oil to the center main under pressure. It looks as if the center main was splash lubricated and the oiler connection was just for show.

 

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Sounds like an engineer had an idea then a “ah, never mind “. We had a few fire hydrants in town that were done like that. They never ran the water lines to them! Of course it took a House fire for the FD to realize it.

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There is an odd "flaw" in the casting on the top that I think is directly opposite the center of the bearing...as if it was originally intended to drill down through the crankcase to the center of the bearing but for some reason they didn't do it. I may very well do that myself although it will require drilling a hole about 7" deep - I have to figure out if putting a fitting there to connect to the oil lines will obstruct the intake manifold...so it's another problem to solve.

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I bolted the fixture up this morning and discovered I still don't have enough travel in the table to get the holes I have to drill under the spindle. In this case because the bolts that hold the steel pieces down obstruct sliding the crankcase back.

 

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So I countersunk the bolt holes for flat head cap screws. With those below the surface I have pretty much unlimited adjustment room. But, with all the nuts and bolts I have, I don't have the right ones and our local hardware store (which is a very good one) didn't have them either. So, I ordered some. They'll be in late tomorrow. In the meantime, I have another job that needs doing so it's worth waiting for the right bolts. I have so much time in this I don't want to take any chances.

 

I also took a look at the center main bearing problem. The casting has a cruciform cross section directly in line with the center of the middle main bearing.

 

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And this odd "flaw" on the upper surface. I'm more convinced than ever that it was supposed to have a hole through the crankcase feeding the center of the middle main but that, for some reason, they didn't drill it. The fact that it has a connection for the oiler but that it goes nowhere is a tip off that they made another cheesy, cost saving modification. I'm not thrilled about drilling this hole but if I'm careful it should be fine. It doesn't have to be very big - just the ID of 1/4" copper tube. This is the top of the case opposite the bearing.

 

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Edited by JV Puleo (see edit history)
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My flat head cap screws cam in so I bolted the extension plates to the table of the mill. I should be back in business tomorrow.

 

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This also arrived. A piece of cored bearing bronze to make the center camshaft bearing.

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With the new flat head bolts in place I set the crankcase up on the mill. You can see how far it hangs over the front and the need for the plates to support it.

 

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I indicated the squared end of the torsion plate. It was out .003 in 6" so I left it alone.

 

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I also double checked the spindle though this is just my paranoia acting up.

 

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I am plunge milling the holes. For this I had to have a special end mill reground since the diameter needed is not a standard end mill size.

 

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It worked quite well.

 

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Then I clamped the cap on taking care not to move anything.

 

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Center drilled it and then drilled it 1/4" for the attaching screws.

 

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Then I took the cap off, threaded the hole and put the first insert in with a drop of Locktite on the threads.

 

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From this point forward when I drilled the 1/4" holes I made sure to put cap screws in the finished holes.

 

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The third hole was a pain in the neck due to the Mitchell companies very liberal idea of what precision means. This hole had a screw broken off in it which, fortunately, was so oxidized in place it didn't move when I drilled it out. I didn't get the entire piece out because the original holes must have been drilled freehand...

 

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It came out all right though... Believe it or not, this took just about all day with 4 or 5 operations that had to be repeated each time but now there are 4 holes in the crankcase and they line up with the new cap.

 

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