But, like you, I’m curious if the material matters. It’s only really a spacer, yet, it would see some rotational force as the loader arm moves up and down
I did have one pin replaced, a machinist I used to know made one up with CNC and a tig welder, as trade for some junk I had, that he wanted. O2 tool steel, CNC cut the cap, tig welded the cap on and flap ground it so you couldn’t even see the tig welds. VERY impressive work but so out of place on a 60 year old machine
It’s hard to ask a professional to “whack it together” when they are used to going at it full bore
Doesn't directly answer your question but figured I would share.
When I need small but precise shims. I waited until PA does a sale on their feeler gauge set. Bought a couple of them and then I take it apart and use them as shims
Worked GLORIOUSLY for me when I was shimming my round column mill.
The calipers seem to want to go to /64’s or /128/s really easily. I don’t know if I can set them to limit at 1/16”
Nothing I do needs 1/128” tolerance.
That's probably something you might consider upgrading & you could probably do it for under $20 for any number of offshore 0.001" resolution verniers. 1/128 is almost 8 thou (0.008") and it probably has a wider +/- tolerance because the upstairs digit has to be an even number. You can work to within a couple thou on even a worn out lathe or mill if you are mindful of backlash & machine finish. But first you need to have an accurate 'ruler'. Even so a regular 0.001" caliper will help you with off the shelf components - bearings, shafts, whatever. If you already have micrometers for this work (which read 0.001" or better) & you are using the calipers in a rougher environment, that's fine too. But I would find it tedious to measure 15/64", get out the calculator... oh that's 0.234" +/- some tolerance fraction of 128... oh wait I need mm, that's 15/64*25.4=5.95mmm... I guess probably close to 6mm.... That style of caliper may have been popularized for non-machinist folks, maybe woodworkers? Nothing wrong with the idea but I think you'll enjoy a regular one more. Just a personal opinion
That's probably something you might consider upgrading & you could probably do it for under $20 for any number of offshore 0.001" resolution verniers. 1/128 is almost 8 thou (0.008") and it probably has a wider +/- tolerance because the upstairs digit has to be an even number. You can work to within a couple thou on even a worn out lathe or mill if you are mindful of backlash & machine finish. But first you need to have an accurate 'ruler'. Even so a regular 0.001" caliper will help you with off the shelf components - bearings, shafts, whatever. If you already have micrometers for this work (which read 0.001" or better) & you are using the calipers in a rougher environment, that's fine too. But I would find it tedious to measure 15/64", get out the calculator... oh that's 0.234" +/- some tolerance fraction of 128... oh wait I need mm, that's 15/64*25.4=5.95mmm... I guess probably close to 6mm.... That style of caliper may have been popularized for non-machinist folks, maybe woodworkers? Nothing wrong with the idea but I think you'll enjoy a regular one more. Just a personal opinion
I think the difference is, most of what I work in is measured in 1/16”-1/8” range, whereas most machinists are used to working in 0.001” increments.
How do I say this- using the pin as an example- it measures 1” OD. The shim, in this case, needs to fit over the 1” pin. I honestly couldn’t care less if the ID of the shim is 1 1/16”-1 1/8” larger than the ID, I just want it to fit around the pin
One of the machinists I used to work with/for hated when I’d say “waller it out to fit”.
I remember getting told to cut a piece of aluminum block at 6”, I used a tape and sharpie, cut it off in the bandsaw and said ok, now what. The boss said measure it, it was 6.079”. He said square it up in the mill, then dress it until it’s 6.000” like I asked.
I get it, I’m just saying for me, 1/16-1/8” is plenty tight for tolerances. I’ve said it before, it’s hard to get a pro to dial back his high standards to cobble a piece together
If it is for spacer washers for a loader arm it would be nice to make them and then hot dip galvanize - that might be a bit over kill. You could machine out of stainless for corrosion resistance but for the most part they could just be mild steel. Machine OD and ID and then part off at thickness required. Make a few spares
Well..... this turned into a day and half's adventure.
Started off with a trip to BB for a 1/2" chuck with MT2 taper. The one I got with the lathe is only 3/8". All my Deming bits are 1/2" shank.
First off, drilling a 1" hole in a 6" length of round stock isn't as simple as it sounds. I had to step up the drill bit size 8 times to achieve 1", and had to repeat that 3 times to bore the entire 6". Add to that, the JT33 taper between the chuck and MT2 taper refused to hold. At one point in time, I had a drill bit buried to the hilt and no means of backing it out. I tried reversing the motor, and guess what... that proceeded to screw the chuck off. Lesson learned with that one. Once I got the drill bit freed from the work piece, I discovered the MT2 taper wasn't going to come out of the tailstock without a battle. Sheesh, must have wasted 4 hours dealing with that situation.
I highly suspect the tapers on the BB chuck and MT2 taper aren't up to snuff. And, that chuck bruised every drill bit shank to boot. Take it back?
This is how much swarth I accumulated, boring a 1" hole in 6" of round stock.
Once I had a usable length bored out, I commenced to part off shims. Shim one and two went ok, but then my tool holder gave out. RATs.
Switch to plan B, use the bandsaw. Well... that went pretty good, until the drilled stock became too short for the bandsaw vice to hold.
Switch to plan C, the power hacksaw. Here I'm down to the wire and one shim short, darn it. The finish from the hacksaw is actually better than the bandsaw for some reason.
The final score. 10 - 1/16", 10 - 1/8" and 9 - 1/4". Not perfect and not pretty.
Sheesh, B-Train's Posts makes me feel like Bubba LOL.
Interesting how a handful of innocent looking parts can consume so much time & killowatt-hours, huh? Welcome to the 'that should take about 20 minutes' Club.
Sometimes its faster to break out the boring bar than labor through big drills, especially on smaller machines. Drills can also start getting fussier on deeper holes - vacating chips, more heat, more friction... Perhaps you could have drilled shorter sections, but then you require a stub to grip in the chuck & end up using more. I've also seen heavy wall tubing which might have given you a head start on opening the bore, but we try & use the material we have. OK Miller Time!
I had two arbours from KBC that were badly ground. Just with my fingers, it was apparent that the jacobs taper portion was not round. Checking with the DTI showed there was a 3 thou 'lump' near one end and next to nothing at the other end. Gory details start at:
But the problem could also be with the socket in the chuck body or with how you assembled it. One firm whack with a hammer is all that is required.
BTW, it is not apparent if you used any lube while drilling? What about the grind on the drills? 8 steps to get to 1 inch seems like too many. Was this mainly because of slipping drills or stalling the lathe?
8 is the number of deming bits in my kit. 9/16"-1". I was doping the bits with cutting fluid every pass.
This is the bit that caused all the grief with respect to the JT33 taper not holding. How I managed to do that is a mystery to me. Too much swarth build up?
Next up are some 1 1/4" X 1 3/4" shims. Going to use a boring bar for that exercise.
Oil, peck, withdraw, clear chips, oil, peck, withdraw, clear chips, repeat. 1/4 inch or less of depth at a time depending on drill size and chip load. Also the bit could be bigger in that spot, grind it out (add relief) after measuring if needed
a little hard to tell from the picture but is your tool height at center? it looks quite low. I think you are trying to part off? Are you using plenty of heavy oil? sulphated oil? I upgraded to a carbide indexable parting tool and it worked quite a bit better. I'm not sure what you are using there. those braze on tools are not always great. It needs to be sharp of course. it has to be very straight 90 degrees to the work - use a square to verify - and lock the carriage. the more rigid the better and small changes help a lot.
re your chuck and drill trouble. Make sure you've cleaned the JT33 and the mating surface of the chuck with a solvent like paint thinner and get it really really clean. use a new clean rag - no trace of anything on the rag should be present. are you willing to eat off it? no? keep cleaning. then after it's put together put it in the tail stock and give it a good whack with a dead blow hammer. I suspect your bits are not sharp if you had to use so many different sizes. with drill bits you really get what you pay for. I ordered a set of 1/2 to 1 from bolt supply warehouse, norseman brand made in usa, it was $200. they work dramatically better. look at toms machining for a very detailed you tube video on bit sharpening. it's not as hard as you might think.
I also bought a set of prentice bits from busy bee for $80. Worst purchase ever. don't buy those. I gave them away and I feel guilty about it.
By chance, are you forgetting to lock your compound dovetail and your carriage (bed axis) so nothing can drift under cutting pressure? ie. the only allowable movement is the cross slide?
How did you make out with the recommendations using the steel rule to center the cutter & ensure it is travelling exactly perpendicular to the stock?
What is your speed? I'd recommend starting on something slow just to see if it improves.
