Werowance attempts Upshur Vertical Single

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werowance

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Got some done on the crank. I don’t have a small enough counter bore for the weights yet but I’ll shop for one. If u see the zebra stripes one one piece that’s jb weld where it got loose from me radiusing the tips and made some mess. Not enough to scrap. I just filled it like wood putty cause I wanted to
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Brian Rupnow

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It looks good. Put one end in the chuck and the tip of your dial indicator on the other end which is unsupported and turn the chuck by hand. Let us know what the run-out is.
 

werowance

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ill try to do that tonight. but what about the runout already in my 3 jaw chuck? would you put a pice of virgin stock in first and find the runout on it then compare it to the runout on the crank as well and subtract the 2 if there is any difference between the 2?
 

werowance

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im shopping for a counterbore for the 4-40 screws and not having much luck. i find some kits that will go down to "#6". any suggestions on what to search for? tried #4 and 4-40 counterbore with no luck and just counterbore which gives way to many results. didnt know if there was another search term or something i need to use.
 

Brian Rupnow

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If your chuck runout is greater than 0.003" total indicated runout, you have problems with your lathe. If it has less than .003" total indicated runout, don't worry about it. Just go ahead and measure the crankshaft the way I said.
 

petertha

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I have tried a few counterbores, good USA brands & crappy clones (the ones with pilot guiding stub on the end). Personally I get no-fuss results with an end mill. Just find the size that gives desired head clearance.
 

Brian Rupnow

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It gets even more complicated. You can buy the counterbore tool with two or three different pilot diameters. Look up what the standard clearance is for a #4-40 fastener, then make sure that you buy a counterbore tool with a pilot that fits that hole. I didn't know about this, and two of the counterbore tools I bought had oversize pilots on them. Since the pilot doesn't do any actual cutting, I was able to mount my heavy duty air die-grinder on the toolpost of my lathe and turn the pilot down to the correct size. If you do like petertha suggests and just plunge with an unpiloted endmill, it will pull itself off center and the counterbore will not be concentric with the bolt hole. Do a web search for cap screw counterbore tool---I just did and there are a dozen different suppliers.
 

werowance

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Ok just measured crank and test rod. Crank and test rod made from scanner slide shafts assuming somewhat precision ground

Both done with about half inch in the chuck to far length. The crank has been made with about an inch overall longer than plans but centered on that for expansion of pulley or something else later

Roughly 3.25” hanging out of chuck

Test rod measure right at chuck .0025. Results at end of test rod same length out .0035

Same test with crank at same positions. Right at chuck .0025 and at end .004.

I have digital indicator that will only go .0000


Is this acceptable?
 

petertha

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If you do like petertha suggests and just plunge with an unpiloted endmill, it will pull itself off center and the counterbore will not be concentric with the bolt hole.
Not sure what to say Brian. These are M3 counterbores of almost 0.5" depth, made with an endmill following the 3mm clearance hole. The bolts drop right in place with no off-center issues, the heads fit the cylinder bolt pattern & secondary fixtures. Similarly a 10mm EM was used to drill a concentric flat bottom counterbore for the valve cage, again concentric to the stem pilot drill hole. More material was pre-drilled before the EM in that case but interestingly the EM has to start its cut tangentially to the hemi combustion chamber shape, so one would think a worse condition for potentially setting a drift angle. Same deal with the inlet/exhaust port drilled at a weird angle to the head.
 

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Brian Rupnow

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Petertha--I wasn't trying to be nasty. What I posted was my experience with using a non piloted endmill to make counterbores. I don't know why it happens, but it happens often enough that I always use piloted counterbore tools.
 

awake

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Interesting - I too have never had an end mill drift in this situation. Maybe a difference in the length of the end mills in question? Or rigidity of the milling machines? Phase of the moon?? :)

I've also made piloted counter bores on two or three occasions, very q & d, by taking a spare twist drill bit and grinding down the last half inch or so to the pilot size while twirling it by hand - no precision at all other than by eye, and making sure the end of the flutes that remain are sharp. You'd think something so crude would chatter up a storm, but in fact they have cut smoothly and easily, giving a beautiful result. Needless to say, YMMV, as may mine the very next time I try this!
 

werowance

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well that's a relief. I was concerned that was a lot of runout on the crank.

so I got to thinking about the counter bore last night. I found the right size drill for the head of the screw, I cant remember but I think it was a #4 might have been a #5. its still on my bench so ill double check tonight. I meant to grab it on my way to work so I could pick up a couple more today. but what I was thinking was to just start a drill hole with the right size drill then take a sacrificial bit of the same size and make a flat bottom drill out of it. I also considered using my tool post grinder (will have to pick up a new cut off wheel for it) and grind a pilot tip like suggested above by Brian and Awake. but I figure a flat bottom drill with a hole already just barely started should give me enough to keep it from walking. its not really that big of a deal for me to have it counter bored but I think it would look better. what do you all think of the idea?
 

awake

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Might work, if the drill bit is short and stiff. If long and flexible, I'd worry about chatter. You could always give it a try in a piece of scrap and see what happens - and if it doesn't work, then grind a pilot on it and try again.
 

Art K

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I have regularly used an endmill to make the counterbore for holes I didn't have in that size. As long as your setup is relatively rigid, I have never had a problem with it.
Art
 

werowance

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i ended up using a flat bottom drill to do the counter bore. i dont own an end mill of the right size.
what i did is just start a hole with the correct size drill on both counter weights, then took the same drill and ground it to a flat bottom. it worked well i think.

also the cross pins, they are peened on both sides, i had chamfered the holes on both sides to give them room to swell out on both sides. they are also loctighted in place as well. the pins were peened until they swelled out to almost double their size. then any excess was cut off with wire cutters, filed and then sanded on a surface plate until uniform with the rest of the piece.


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werowance

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still waiting on my gear cutters to arrive which will almost complete my set of cutters. so last night after the crank i started on the tappet guides. which brings up a question. the part that rides against the cam. seems some call them tappets, some call them lifters and some call them cam followers? am i correct in that all 3 names are the same thing?
 

werowance

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cant be in the shop right now so messing around with the possibility of 3d printing the gear cover. plans say can be made of brass or etc and epoxied on the outside case so i thought why not just 3d print it. it really should be measured from the actual gear and slot cut in crank case for clearance but this one is more just to see if it can be printed and if i have to have supports and etc in the print.

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