JV Puleo

My 1910 Mitchell "parts car" project

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A few weeks ago I also got this...

 

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It is combination planer/shaper made by Lynd & Farquar of Boston. This should be a really useful machine... I can plane a few thousandths off the top of my crankcase with it to get it perfectly flat as well as make a few other parts that have, until now, stumped me, like the dog teeth on the crankshaft hub and hand crank. This machine was introduced in 1917. I'm not sure when this one was made but it has a factory motor mount where the earliest version was driven by overhead flat belts. I've come to the conclusion that it is often easier to fix early machines, like my Mitchell, using the sort of machine tools the parts were designed to be made on.

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Thanks, Terry. I'm pleased with it. I wanted a shaper and didn't think I'd ever have a planer. Now it looks as if I have both.

 

Here's the end of the oil filler/breather episode:

The first step in finishing the cap was to drill and ream a 5/8" hole in that flat piece of brass. It's much thicker than it will be when finished but this isn't a problem and will be a help in machining it.

 

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I then put it back in the lathe to turn it round and reduce it to 1-1/2" This technique is awkward because it's hard to find a way to hold it securely enough so that you can turn the corners off. It would be better to cut the corners off first, but I don't have the proper tools for that.

 

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Still, it only took about 10 or 15 minutes to get this...

 

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I then set up the threading tool and threaded the OD so that it would screw into the cap piece and make the top.

 

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The thread, in this case, is slightly loose. This was intentional, allowing its exact depth to be easily adjusted and room for the solder that will attach it to the cap to flow completely through the joint between the two pieces.

 

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I used my camp stove soldering technique shown earlier. This time it worked perfectly. I put some flux on the threads, inserted the top piece and adjusted it. When it was up to soldering temperature I just touched the wire to the inside edge being very careful not to touch the inside threads. I used 50/50 solder which flows much more easily and uniformly than any of the low lead or lead-free solders I've tried. You can just make out the solder line on the top of the cap.

 

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With the cap soldered, I screwed it on to the filler tube and put that back in the lathe. It will serve as a holding fixture while I machine the cap. You can see why I wanted the outside and inside diameters to be concentric. Threaded joints are not absolutely concentric except in the position where the thread stops but this will give me the nearest thing possible to a perfectly concentric cap.

 

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The face and the sides of the cap were then turned to finished size. Where they were between .250 and .375 thick, they are now about .100. I also threaded the hole in the cap to 3/8NPT. McMaster Carr sells a nice breather valve in 1/2 and 3/8 NPT. I will put one in the top of the breather tube and the other in the side of the crankcase where the original filler tube was. The last step was knurling the outside of the cap. This not only makes it reasonable to unscrew with oily hands, it gives it a very original appearance. It is, however, not as easily done as it looks. The pressure needed to push the knurling tool against the piece is great and it is necessary that it be very securely mounted. Even then, I made four passes... when doing this, you cannot let the wheels lose contact with the surface. You'll never get them back in the same place so you have to traverse the piece,  stop before the wheels lose contact and then reverse the feed.

 

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The result, if you are careful, it quite nice though it leaves a burr on the edge. Here I'm removing the burr and giving it a slight chamfer. The real challenge is now getting the cap off. The pressure from turning and knurling has screwed it on as tight as it can be and you don't want to damage the knurl by using vice grips. I wrapped it with leather and tried unscrewing it by hand. Much to my surprise, it came off so the worst problem was averted.

 

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And here it is with the top screwed on. This is done now, except for inserting the breather valve.

 

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Edited by JV Puleo
pictures in wrong order (see edit history)
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Like magic...  Hard to even believe that could be done but yet when you show it step by step, it looks fairly straightforward.   I couldn't yet do that, but I can understand how at least.

 

 

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It's just a matter of trying and, if things go wrong, trying again. You learn as much from the mistakes as you do from the successes, or to steal an old dictum from the Talmud, "every misfortune is an opportunity." I keep a box full of my errors and more than once I've gone back and used the pieces again. The top of this cap was one of those.

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Sometimes I find myself asking "why didn't I think of that before"? The last little job, the oil filler, gave me an idea to solve a long-standing problem. I want to replace the intake manifold with one that is actually calibrated to the displacement of the engine. The Mitchell factory purposely de-tuned the engine, I suspect because it was unbalanced and was theoretically capable of greater RPMs than it could safely turn. I based the dimensions of the new manifold on the formula in Heldt's engineering text. It requires an inside diameter of about 1.65 to 1.70" - just about the correct size for 1-3/4OD tubing. But, the tubing has to pass between the blocks and include a provision to attach the carburetor unless you are willing to remove the jugs in order to remove the intake. A coupling that could be made airtight is needed so that the two halves of the manifold can be joined.

 

Making the cap for the oil filler gave me the answer. Even though I really should have been doing other things, I had to try and make the coupling. This is what I came up with...

The outside diameter of the threaded collar just fits between the jugs.

 

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The threaded collar will be soldered to one side of the tubing. The other side will screw over it with a viton-ring as a seal. I'm planning to use copper tubing - not the brass tubing shown here, but haven't bought it yet. I also have to make patterns to have the fittings needed cast but have hesitated to start that project until I was sure I could come up with a convincing way of joining the two halves of the manifold. The finished product will look quite like the manifolds used on the RR Silver Ghost and other high-quality cars.

Edited by JV Puleo (see edit history)
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I'm back from my annual trip to the UK and recovered enough to get a few things done. The coupling for the new intake manifold was so successful that I'm inspired to finish the rest of the job. The manifold will be made from 1-3/4" OD copper tubing, very much in the style of a Silver Ghost RR. The tubing part is easy enough but it also requires a "T" junction, two right angles and a 45-degree angle. If I were as clever as my friend Terry Harper, I'd make patterns and have them cast but I thought to try something different first. This piece is the "T" junction. It is made from a 1-1/4" bronze pipe fitting. The first step was to macine off the double thickness reinforcing rings on the end of each arm where the pipe screws in. This was done by indicating a piece of threaded pipe in the lathe and screwing the fitting to it to get it centered on the thread. I neglected to take a picture before I started so here it is in the lathe with the first step completed.

 

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I centered it on the newly turned surface prior to boring out the threads.

 

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It worked quite well... in fact, I only had to hone it a bit when done to get the fit just perfect.

You can see that when bored out, all the casting roughness is gone from the inside as well. The OD of the pipe fitting is just under 2" so the wall thickness is about .100. This is just about perfect.

 

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The fitting will be slipped over the copper tubing with another hole in the tubing where the perpendicular section joins it. The idea is to get as smooth a surface on the inside of the manifold as possible.

 

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The next time I'm in the shop (we're expecting snow tomorrow) I will bore the middle section in the milling machine.

 

Edited by JV Puleo (see edit history)
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Well, the snow never came so I was back in the shop and bored the perpendicular hole in the T fitting.

 

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I'm satisfied with this. It looks as if the holes are perpendicular to each other and the copper tubing is a tight fit. Actually, it is a bit too tight so I'll probably have to hone the bores a little but too tight is much better than too loose... then I'd have to start over.

 

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The next operation are the right angles. These are made from pipe fitting as well but are a lot more complicated.

 

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The first step is to turn the reinforcing ring off one side. I chose the side that has "Thailand" cast into it. These appear to be quite well made. The inside surfaces are smooth (for a casting) and, so far, none have run out dramatically.

 

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While I was at it, I did the 45-degree fitting as well.

 

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This is where the job starts to get complicated. One of the problems I'm facing is that the machine work on this car was not very good. Where you would expect things to be identical, there are major issues. One of these is the intake manifold flanges. One of the flanges is reasonably symmetrical. The was wildly off. I suspect that it was drilled with the manifold in place. When I machined the jugs, I plugged one of the stud holes and re-drilled closer to where it should have been. The other hole is slightly off as well but is so close that the plug would have been very thin... You can see the old hole (at the bottom) and the new one in this photograph.

 

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So... I have to make 2 flanges to fit the holes, which are not in perfect alignment, that include right angle fittings that must be in perfect alignment. How to do this has been something I've been thinking of for a long time and I am not certain what I am going to try will work... however, it's "nothing ventured, nothing gained."

This is also one of those projects where I may spend more time (and money) on the fixtures than I do on actually making the part. The first step is to turn the reinforce ring on the other side of the right angle to 2.080 inches. I'm going to thread this and, if I did the math correctly, this should thread into a 2" hole in the flange.

 

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The goal here is to make both pieces as identical as possible because I will thread both flanges at the same time. I was going to thread the right angles today but have discovered that my threading tool will not fit in the space available. Tomorrow I'll see if I can grind a new one. The flanges will be turned round and the right angles threaded into them. With a piece of the copper tube in place they will be aligned with the holes in the blocks. When the holes in the flanges are drilled I can then machine the lozenge shape using them as a guide. That's the plan in any case, we'll have to see if it works!

Edited by JV Puleo (see edit history)

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Here are the finished "elbows." This was a bit tricky to do but I'm satisfied with the way they came out.

 

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The next step is to make the flanges. I started with two pieces of 1/2" brass plate, roughly 4" x 4-1/2" and drilled and tapped 1/4" holes in the corners. The circle scribed on the surface shows roughly what the size of the finished piece will be.

 

 

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With the two plates bolted together, I put in a center hole to aid in aligning it in the lathe.

 

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The two plates were then centered in my big 4-jaw chuck, trying to get them as perpendicular to the bed as possible. It is really impossible to get the alignment perfect.

 

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With the plates locked up in the chuck, I drilled, bored and reamed it to 2". If I did the math correctly, the thread diameter on the elbows will work with a 2" hole.

 

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The hole was then threaded to match the elbows...

 

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The fit is pretty tight... which is good and it looks as if I did do the math correctly!

 

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Next, I have to make some holding fixtures. I confess that this project has thrown me some curve balls I didn't anticipate. Holding the pieces so I can machine them is proving a problem. It looks as if I will need all of this material and the little tilting table to make these parts.

 

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The 3" piece,  2-1/2" in diameter was chucked up in the lathe, carefully indicated and then bored and reamed to 1-1/2" The hole in the center will allow it to be held by an expanding mandrel.

 

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Mounted on the expanding mandrel, I turned the OD a few thousandths to make sure the OD and ID were concentric. Then, I turned down the end and threaded it to match the hole in the flanges.

 

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Here are the threaded holding fixture and the plates that will be the intake flanges.

 

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The fixture goes back into the chuck,  carefully indicated, the plates screwed on and the 1/4" cap screws in the corners removed.

 

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I then turned it round. This is time-consuming and puts a lot of stress on the workpiece, especially early in the job where you are just knocking off the corners. If I had a metal cutting band saw, I'd have cut the round piece out roughly to shape. Unfortunately, my antique reciprocating saw isn't that flexible. However, it is just tedious, not difficult. The finished size is 3.7"... calculated to be the largest width of the flanges.

 

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Before I can regard this part of the job as finished, I need to make certain that the face of the flange that meets the block is absolutely perpendicular to the threads. The partly removed dychem on the surface shows that the setup in the chuck wasn't perfect - nor did I expect it to be. I only removed about .015 to get the surface perfectly flat.

 

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From here it was short work to finish facing the two flanges. The elbows screw in - perhaps a little bit tighter than I'd anticipated but, in this case, I am making something that would have been cast as one piece in period so it isn't critical that it ever be able to come apart.

 

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Next, I'll be machining away about half the thickness of the flanges, leaving a reinforce in the center, and making the holding fixture to bore the ends of the elbows and the 45-degree fitting...

Edited by JV Puleo
imporvements (see edit history)
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Here are the flanges, now machined so that they are only about 1/4" thick with a raised section in the middle for the threads.

 

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Nice job... took me a couple of read throughs to understand that the non-brass part was a fixture to hold the flange so you could turn it and probably other steps to come.  I think I got mesmerized by the nice pictures and didn't read the captions!!

 

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It is more complicated than I expected... though I'm not sure what I expected. Sometimes, I just start on the part of the job I know how to do and hope I'll be able to figure out a way to go forward. The next step is another holding fixture... I'm really anxious to turn the lozenge shapes because I think I have a way to do it almost perfectly but that will have to wait until I can assemble the pieces on the engine to make sure everything is in proper alignment.

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Here is the next step – a fixture to hold the elbows firmly while boring them. Starting with two blocks of aluminum 1-1/2" thick and 4" x 4-1/2". This is going to be a clamp... I've drilled and tapped the four corners.

 

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and screwed the two blocks together to get a block 3" thick and 4 x 4-1/2

 

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This goes back into the big chuck and is centered. I don't know of any good way to indicate a rectangle so this had to be done by eye using carefully measured scribed lines on the end of the block. Fortunately, it doesn't have to be absolutely perfect.

 

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When I got it to where I thought it was centered, I faced the end off. This began life as a block about 9" long that I cut in half so this end had the two surfaces made by my old-fashioned power hack saw. They weren't smooth or perfectly straight...you can see the saw marks on them.

 

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With the hole bored, I clamped in a piece of 2" bar. the block was mounted on the milling machine with the bar supported by a pair of V-blocks and a few thousandths taken off the bottom surface. this assures that the bottom will be perfectly parallel to the piece in the clamp. I also drilled two holes for mounting on the table of the milling machine and shaved a few thousandths off the upper side of the bottom piece - this is to give a very slight pinch.

 

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That last part of this clamp is to make two split bushings. One 1.670" diameter to hold 1-1/4" pipe and the other 1-3/4" diameter to hold the copper tubing the manifold will be made of. The purpose here is to hold the pieces firmly enough to machine them while, at the same time, not deform them by squeezing them in a vise. I cut the piece of 2" bar in half and started on the bushings...

 

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Here is the finished fixture with the two spit bushings.

 

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I clamped a piece of 1-3/4 brass tubing in it as a test. Everything is pretty tight - maybe a little too tight to make it easy to use but I think it will work just fine.

 

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There is nothing to do now but try it out so I screwed one of the elbows to a short piece of pipe and set it up on the milling machine.

 

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The final test will have to wait until tomorrow. It was near the end of the day when I finished this and not the time to start fresh on a new, precise operation.

The pipe nipple and aluminum plug are for centering under the boring head and checking the level. The mill is actually off level by a few thousandths. I put the level on top of the plug and matched the reading to that of the table. That way it should be as close as I can possibly make it.

Edited by JV Puleo (see edit history)

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It worked pretty well. It is difficult to be sure everything was perfectly centered...Pipe threads aren't the optimum thing to measure from but if the inaccuracies are invisible to the human eye. I'm not worrying too much. This design has enough adjustment in it to compensate for just about any small differences. Here I'm boring out the threads with a boring head.

 

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One came out a few thousandths too big and the other, a few too small. the bigger one will still work fine but I'll have to make an expansion lap to fix the other. That is a job I need to do in any case. I've never made one and have to to fit the crankshaft gear so this will be good practice. It is a little more time but the ultimate result will be better.

 

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Joe, looking nice.  Do you have a picture of the original parts that you're making?  Maybe where it fits on the engine? 

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Actually, in this case, I have the original part. I just don't like it and, like so many parts of this car, it wasn't particularly well made, to begin with. I'm getting close to fitting the parts at which point I'll show how it mounts on the engine and what the attendant problems are. I don't have an exhaust manifold and that one will probably require some welding - something I don't know how to do so that should be interesting. I'm on the fence as to whether I should try to teach myself how to use the mig welder I inherited or maybe just get it done by someone who knows what they are doing.

 

I confess that this manifold doesn't look anything like the original... I'm basing it on the RR Silver Ghost manifold that I've always liked. One of the characteristics of these cars is that they were frequently under carburated and sometimes (as in this case) had manifolds that purposely restricted the intake flow. I believe this was done because with such an unbalanced engine they could literally shake themselves to pieces - or worse, something would let go. I'm making no claim to "restoration" here... I want the best Edwardian car I can build. I am limiting myself to the technology readily available during the cars working life - maybe 5 years - so I have a cut-off date for "improvements" of 1915.

 

 

Edited by JV Puleo (see edit history)
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Nice work Joe,  I would also like to see the original in place as compared to your upgrade manifold.  I am hoping for a set of new castings that I can use to build the intake manifold  for the Model M Wisconsin "T" head engine.  (First things first)

Al

Edited by alsfarms
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Here is the original manifold... it's cast iron and quite heavy. The long curved part passes between the jugs because the carburetor is on the opposite side of the engine. The second photo is of the flange where the carburetor attaches. The ports in the blocks are about 1.6" in diameter but the inlet port at the carb end of the manifold is just 1.25" in diameter. That is a considerable reduction in volume. According to PM Heldt's discussion of intake manifolds, the 1.6" diameter is just about perfect for an engine of this displacement (just short of 300 ci) so my goal is to get a manifold of that inside diameter.

 

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Here's the engine showing the two intake ports. The manifold will bolt on here and pass through the blocks. The distance between them is the limiting factor on the size of the tubing as I also have to accommodate a coupling on the opposite side that is air tight.

 

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The valve cages, cam followers, valve caps, rocker arms and push rods are all items I've made over the last few years. It was in making the valve cages that I learned the trick of turning the lozenge shape needed for the manifold flanges.

Edited by JV Puleo (see edit history)
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It really is brilliant, thanks for posting the extra pictures to give us some context!!

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You are certainly doing a fine job with your machine work.  As I have read and put an "eye" to you project and fixtures, I am given a few ideas on how I could overcome some of my "headaches".  Keep up the good work.

Al

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You'll remember I said that two of the holes I'd bored were very slightly undersized. It is a special problem taking a hole out only a few thousandths. For this, I made an expandable lap. This is something I'd read about but it is the first time I'd tried it. The lap was made from a piece of 1-3/4 aluminum bar. I drilled it through and tapped one end 1/2-20 and the other with a 1/4-18 straight pipe thread. The diameter was just slightly skimmed to make it about .003 smaller than the original size. It was then slit so that the end would expand slightly when a tapered pipe plug was screwed in. I screwed a #3 morse taper adapter for a screw-on chuck into the other end.

 

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The "T" section went in the drill press and the lap, coated with 120 grit Clover grinding paste was gently run in. When it moved easily, I expanded it a small amount with the pipe plug.

 

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It took much less time to fit the copper tubes than it did to make the lap.

 

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I then set the elbow that was slightly undersized in the fixture I made to hold it while boring and did that one as well. I am only removing about .002 to .003 here. Lapping isn't really feasible for anything above .010 but it is perfect for a fine fit when the tolerances are already close.

 

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So there's nothing on the lap but the paste?   

Did you fabricate the hold downs or is that something easily purchased?

 

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