9" SM Utilathe Restoration
- Thread starter YYCHM
- Start date
Brent H
Ultra Member
Is the back plate thick enough to machine flat and redo the fit? All new back plates need machining. You should be able to flatten it and machine a new fit.
You need to make sure you make the headstock 90° to the bed way first. Or the face plate machines zero across the face.
Take a thin cut across face and then run dial indicator across - should be 0 to 0 from near to far
You need to make sure you make the headstock 90° to the bed way first. Or the face plate machines zero across the face.
Take a thin cut across face and then run dial indicator across - should be 0 to 0 from near to far
trlvn
Ultra Member
That question seems to incite religious wars!
"Oil gets flung out while spinning."
"Grease attracts swarf."
FWIW, I used grease on the gears on the _inside_ of the chuck. I sprayed a dry lube on the scroll side so it would hopefully not fill up with swarf.
Craig
I hear you about the debate LOL, couldn't find a consensus on the web so I posed the question here.
I greased the inside gears and lightly oiled the scroll side. Makes sense to me.
Now..... having reinstalled the chuck, the chuck body runout is a dismal 0.015" !!! It was 0.005" before I dismounted it, and I'm sure I mounted it in the same orientation it came off in. One step forward two steps back.
Craig
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historicalarms
Ultra Member
Dry as dry can be, any lube will just compound the scarfe build-up. All of the "moving pieces" are hardened and the limited amount of movement we subject them to with just a hand tool (chuck wrench) wont damage them in any way and it should be dry enough in your basement that rust/oxidization wont affect the chuck neither.
My shop is subject to weather changes and therefore some condensation will start a little discoloration of the chuck outside body from time to time but internally it is perfectly fine.
My shop is subject to weather changes and therefore some condensation will start a little discoloration of the chuck outside body from time to time but internally it is perfectly fine.
Phew..... got her back to 0.005". I tried all three possible chuck orientations and the best was what I thought was the original. Still I had to tap her over a good 0.02". Need to mark this orientation permanently now.
So, I guess this would mean I have to turn 0.002" off the mounting plate boss in order to attain 0.003". Does that sound correct?
I don't feel confident enough in my machining skills to actually attempt it.
Craig
So, I guess this would mean I have to turn 0.002" off the mounting plate boss in order to attain 0.003". Does that sound correct?
I don't feel confident enough in my machining skills to actually attempt it.
Craig
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I’ll give an example. Let’s say you have a dial test indicator (DTI) resting on the OD top of a perfectly accurate hardened dowel pin held in the chuck jaws. It measures +0.001” (high) and -0.003” (low). We calculate runout by (low – high) / 2. Runout = (-0.003 – 0.001) / 2 = (-0.004)/2 = -0.002”. This means the dowel axis is 0.002” lower than the spindle axis. Remember to obey the corresponding low & high sequence order in the brackets and also the +/- sign, then it always works regardless of DTI readings. I've attached a sample of different reading combinations. It doesn't matter if you null the needle to zero at a low or high position as long as you follow the procedure.
Now we have established runout and want to correct the chuck so the dowel axis is 0.000” meaning coincident with the spindle axis. This presumes the chuck recess is completely flush tight against the back plate lip in the offending direction, i.e. you can’t alter it anymore to improve the runout. You need to remove the same 0.002” on the offending side of the back plate lip in order to displace the chuck that amount. But that is equivalent to a radius which means the back plate lip diameter must be reduced by 2 times that: 2 * 0.002 = 0.004”.
Notice we are talking about runout of the dowel reference part held the chuck jaws, not the chuck body or any other unrelated feature. However, if the chuck jaws grip the dowel inconsistently or non-repeatedly, then all bets are off. This problem is common in 3 jaw / scroll chucks, more-so older, worn chucks. Count yourself lucky if you are within 0.001” runout. Before you do any back plate machining or jaw grinding, check this first. Grip the dowel, measure runout, mark the amount and direction with a felt pen on the chuck. Remove the dowel, unwind the scroll & repeat a few times. Ideally same tightness & across all key slots. Also chuck a larger diameter dowel to see if readings vary. If the readings are consistent amount and direction, its probably chuck/spindle alignment. If the readings are dancing around, then its probably jaw related (assuming spindle is in good shape). If the chuck scroll is in good shape, maybe you can buy a set of new jaws & be back in business.
If jaws are unobtanium or the chuck is a direct screw mount to spindle with no intermediary backplate (lip), then jaw grinding is probably the next step. Some guys have no problems taking this on, but do some research as to equipment involved & how to properly pre-load the jaws.
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In my quest to delete the 3.5" risers on my machine I ended up purchasing a parts machine located in Ontario LOL.
All the gory details can be found in this thread https://canadianhobbymetalworkers.com/threads/in-need-of-a-gear.1686/ Was fun to say the least and I made some long distance friends in the process.
Here are the correct gears installed on my machine.
Here is the threading dial indicator I got in the deal.
And I scored this nice chip/drip tray.
Tail stock to spindle alignment looks good.
A bit of a problem here, the tool post that came with the riser kit is too tall. I may cut it down, haven't decided yet.
I have this height adjustable tool post that I could make work. I think it's robust enough?
Next up is installing the rear gear train cover. I've run out of room between the lathe and my mill, so have to decide what to do about that.
Many Many Many thanks to Brent and David for helping me get all this stuff to Alberta.
Craig
All the gory details can be found in this thread https://canadianhobbymetalworkers.com/threads/in-need-of-a-gear.1686/ Was fun to say the least and I made some long distance friends in the process.
Here are the correct gears installed on my machine.
Here is the threading dial indicator I got in the deal.
And I scored this nice chip/drip tray.
Tail stock to spindle alignment looks good.
A bit of a problem here, the tool post that came with the riser kit is too tall. I may cut it down, haven't decided yet.
I have this height adjustable tool post that I could make work. I think it's robust enough?
Next up is installing the rear gear train cover. I've run out of room between the lathe and my mill, so have to decide what to do about that.
Many Many Many thanks to Brent and David for helping me get all this stuff to Alberta.
Craig
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Got the gear cover installed today. Really helps noise wise. Also installed an ESD SW.
Had to mod my mill table to accommodate opening the gear cover LOL. Rapidly running out of room in my humble shop space.
This is the 4 jaw I snagged. It's huge compared to the 3 jaw. Can't wait to try it out.
Got the tool post, steady rest and tail stock all sorted out now.
Pretty much complete other than two missing gits oilers. RobinHood has a couple of those, I just need to make time to pick them up.
I suppose a face plate would be nice to have. I wonder what the head stock dead center taper is for these things are?
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You will laugh at this one, or simply write me off as a Darwin award candidate.
I needed to make some new hold down bolts for the tool post, steady rest and tail stock. The bolts I have are 3 1/2" too long.
Well.... I decided to make the bolts from ready rod and not feeling like hauling out the hack saw, I thought use the band saw. I clamped firmly but not excessively not wanting to damage the threads on the unused rod.
Upon applying power, the saw blade spun the ready rod, which then proceeded to unscrew itself from the bandsaw clamp as the saw blade followed the threads (or did the threads follow the sawblade?) at a very high rate. YIKES! I lifted the bandsaw head, and shut down. LMAO, how stupid is stupid.
Things went much better on my power hacksaw.
Maybe we could use a Lessons Learned topic AKA. How NOT to do things topic.
I needed to make some new hold down bolts for the tool post, steady rest and tail stock. The bolts I have are 3 1/2" too long.
Well.... I decided to make the bolts from ready rod and not feeling like hauling out the hack saw, I thought use the band saw. I clamped firmly but not excessively not wanting to damage the threads on the unused rod.
Upon applying power, the saw blade spun the ready rod, which then proceeded to unscrew itself from the bandsaw clamp as the saw blade followed the threads (or did the threads follow the sawblade?) at a very high rate. YIKES! I lifted the bandsaw head, and shut down. LMAO, how stupid is stupid.
Things went much better on my power hacksaw.
Maybe we could use a Lessons Learned topic AKA. How NOT to do things topic.
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On a more serious note.
Should I be concerned with this gear misalignment? It's there, you can see it, and feel it. Haven't figured out how to measure it. The only way to eliminate it, is to push the idler gear on to it's bushing deeper or mill the back side of the bushing.
Thoughts?
Should I be concerned with this gear misalignment? It's there, you can see it, and feel it. Haven't figured out how to measure it. The only way to eliminate it, is to push the idler gear on to it's bushing deeper or mill the back side of the bushing.
Thoughts?
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historicalarms
Ultra Member
that gear mesh wont hurt a bit, not enough "pressure" exerted on those gears to do any damage in a lifetime of use.
and a tip over your trials of cutting ready-rod in your bandsaw...just cut a slot in one side of a couple of nuts that correspond to the r-r size & pitch. thread them onto the rod, positioning the slot so that it is upright and will be positioned where the holding jaws will pinch the nuts closed a bit on the r-r threads, easily stop's the spin.
I took the time to split a pair of nuts every time I had to cut a different sized rod and retained them for safe keeping, I now have a complete set from 1/4 up to 1" for quick use when needed.
and a tip over your trials of cutting ready-rod in your bandsaw...just cut a slot in one side of a couple of nuts that correspond to the r-r size & pitch. thread them onto the rod, positioning the slot so that it is upright and will be positioned where the holding jaws will pinch the nuts closed a bit on the r-r threads, easily stop's the spin.
I took the time to split a pair of nuts every time I had to cut a different sized rod and retained them for safe keeping, I now have a complete set from 1/4 up to 1" for quick use when needed.
Johnwa
Ultra Member
Good idea! Split nuts work great for holding threaded rod in a 3 jaw too. I’ve never thought about having a set of them. Instead I have a few split nuts in some random spots.
Split nuts is a good idea although I've had to continue the cut through the other side a bit, albeit that was on a lathe chuck setup. In any case there isn't a lot of vise contact area on the tangent of a circular section & now that is greatly reduced by removing thread material. Only the crown of each thread is contacting. Generally in a vise setup if I think its iffy. I will just insert a scrap piece of wood in there. It crushes ever so slightly & makes for more friction. Also in your case, protects the threads from getting marred & then potential issues with using that section for another project.
Well, it looks like this tool holder ain't up to the task. I was attempting to part off some shims and it kept spinning out of alignment. Too much tool offset. When I torqued her down as hard as I could, I pulled the mounting bolt right out of the T-NUT. Stripped the T-NUT threads. Tomorrow those bolts get mig'd to their T-NUTS.
Broke my part off blade in the process.
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Something doesn't seem right for that amount of force. My hunch is some combination of factors. The parting tool tip not ground quite right, either rake or sharpness.... Or not positioned to center axis of the bar stock looking on end. Or its going in at a slight angle vs. perpendicular & getting bound up. Or if you are using one of those bevel top profiles, it might be drawing that side it into the work & binding. I usually part with a neutral tool unless I have a rigid setup. If the cutter is in good shape the finish is about the same. The chips should ideally be nice even little curls vacating out of the slot (but crappy alloys can mess this a bit). Occasional bit of cutting oil to keep the tool happy. Overly heavy feed pressure on the dial means something is not right.
Since you already have a hole, I would recommend choking up on the amount the blade extends by a LOT unless I'm missing something. All you have to do is get through the annular section, not part to the center. The more it extends, the more flex & chance of chatter.
*EDIT* see post #41, I think we are seeing the rear of the parting blade so disregard, although you should still strive for minimal stick out
What did your chips look like? Did it feel like the tool was digging either side to side or up/down?
Since you already have a hole, I would recommend choking up on the amount the blade extends by a LOT unless I'm missing something. All you have to do is get through the annular section, not part to the center. The more it extends, the more flex & chance of chatter.
*EDIT* see post #41, I think we are seeing the rear of the parting blade so disregard, although you should still strive for minimal stick out
What did your chips look like? Did it feel like the tool was digging either side to side or up/down?
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trlvn
Ultra Member
@PeterT has made a lot of good suggestions. One thing I'd add is to check the interface between your tool post and the compound. That is a shop-made spacer block in between, right? Does it sit flat on the compound and does the tool post sit flat on it? If it is permitting any sort of rocking or flexing motion, that might explain your results.
Craig
Craig