9" SM Utilathe Restoration

[YYCHM]

I picked up this 9" Utilathe (Thanks Phil) that's in pretty decent shape for it's age IMHO.



Note the headstock, tailstock, and tool post risers (3"). I want to delete those but unfortunately I'm missing the original 16T headstock drive gear and idler gear bracket.



This is the original gear train.



This is the gear train with the risers installed. Same gear ratio as the original just different sizes to accommodate the risers.



While in the process of re-assembling the machine and thought I would see if the main gears would mesh without the idler and risers installed.

Well.... they do within 0.09". That's how much I would have to shim the headstock higher.

The question I have for you all is. Is this a viable configuration in the first place (i.e. running with the idler deleted)?

 

[YYCHM]

No comments on my gear train dilemma?

Is my proposal feasible at all or a bad idea?

 

[Brent H]

Hey Craig,

I 'll get things going: Should work as your ratio is correct.

Issues: Gotta shim carefully, backlash would need to be figured in, but should be small maybe 5 to 6 thou?

Alignment of the head stock and the cross feed and keeping those gears all nice? perhaps it is all straight?

Less teeth in contact taking up the load on the feed?

maybe others have ideas ?

 

[RobinHood]

I would see if I could shim the QC gear box the 9 thou. That would allow the headstock to remain in its original position and thus would be at the same level as the tailstock.
Just make sure the leadscrew is not bending and you can still move the carriage freely all the way to the headstock without it binding.
If that does not work, your only choice (using your two gears at hand) is to shim the headstock, which would require the corresponding tailstock shim as well.

 

[YYCHM]

Drop the Feed Box. Brilliant!!! That would never have occurred to me. Easy enough to try.

Thanks!

Well.... I tried it. The carriage runs end to end just fine, no binding. The half nut however, does not fully engage, which makes sense once you think about it. The nut would need to be lowered which a no go.

Back to the drawing board.

BTB - The gear I'm missing is 28T not 16T as stated in my OP.

 

[YYCHM]

Did some runout checks today.

The headstock spindle runout is < 0.0005". Hardly registers on my TDI.

The face plate (chuck mounting plate?) runout looks to be 0.004" and the chuck body runout measured 0.005"

A chucked endmill shank measured 0.007".

Looks like I need to do some chuck tuning. It's a 3 jaw chuck, that's bolted(3) to a mounting plate that spins onto the spindle (if that makes sense?).

Apparently I can try loosening the chuck bolts and nudging the chuck over a bit to improve it's runout? Anyone have experience doing this kind of thing?

 

[RobinHood]

Apparently I can try loosening the chuck bolts and nudging the chuck over a bit to improve it's runout? Anyone have experience doing this kind of thing?

Yes, if the register in the back of the chuck allows. When you have the chuck off the backing plate, check runout of the plate. Remove it from the spindle and reinstall to see if it repeats. If not, then you have a plate-to-spindle register issue.

If all the above checks out and you have determined for sure it is the chuck body, you may then machine the backplate-to-chuck register a bit smaller to allow for the chuck to be bumped around. Also, check that there is room for the bolts to shift a bit. You may have to enlarge the bolt holes as well.

Stefan Gotteswinter has a video out on doing just that - he ends up with near zero runout on his “non-adjustable” 3J.

I have done the same to an old Chinese 3J. Together with regrinding the jaws themselves, it turned out to be a very respectable scroll chuck.

 

[YYCHM]

Spent the last three mornings or so (an hour here, an hour there before work) making a shoe for the taper attachment.



The slot in that thing is 1.2" wide and 0.6" deep. It took 120 passes on my mini-mill and toasted a nice 6flt 7/8" end mill. The RPMs were correct according to LMS's cutting speed calculator, and I took 0.01 cuts. What's the expected life time of an endmill anyways? I seem to be going through a LOT!



This was an interesting discovery. That screw and bushing locks the cross slide nut, you remove it (which allows the cross slide to float) and screw it into the TA saddle extension like so. Look at how much smaller the bushing v.s. the extension slot is? Seems to work, but wasn't expecting that kind of discrepancy.



Sample taper cut using the TA. That's 10deg (Max) over about an inch. Ya, I could have done that with the compound but I was curious. Too much stick out on the sample, hence the poor finish. Should have set up using then tail stock, but didn't feel like it. The silly tail stock riser weights in at 45 lbs.



This thing is really loud with the lead screw engaged! Like... wear hearing protection loud. It's all coming from this gear train. With out engaging the lead screw it's smooth as silk and just hums along?

Have to come up with a safety guard/cover for those gears soon. Just an accident waiting to happen.

 

[RobinHood]

toasted a nice 6flt 7/8" end mill. The RPMs were correct according to LMS's cutting speed calculator, and I took 0.01 cuts.

Probably not enough feed rate. I learned the hard way with a 1” rougher in some mystery alloy: burnt up a SKF & DORMER Cobalt endmill by not feeding it fast enough. I also probably ran the first endmill too fast.

Here is the toasted one:


And its buddy that was run afterwards for many feet at 160 rpm, 2”/min feed and 0.050 DOC. Still very sharp.


They both started out brand new.

Time to set up the T&C to sharpen some endmills - some day

 

[YYCHM]

Time to set up the T&C to sharpen some endmills - some day

Sooner than later please. I have a box of larger end mills (1/2" - 1") that desperately need attention.

 

[RobinHood]

Sooner than later please. I have a box of larger end mills (1/2" - 1") that desperately need attention.

Noted...

 

[PeterT]

Stefan Gotteswinter has a video out on doing just that - he ends up with near zero runout on his “non-adjustable” 3J.

Stefan has another vid where he does a mini teardown review of Asian 5C collet chuck and then dials it very true on the lathe. It is a front mount style. I'd have to watch again but I recall he machined the backplate in-situ on the lathe but the step is slightly undersized so the mating chuck recess is not engaged with a tight fit which is the norm. I don't know the undersize allowance number but lets call it 0.005" diametric as opposed to 0.001" sliding fit. This allows him to loosen the bolts a bit & dial the chuck true (within .005/2=.0025 float). You grip an accurate dowel pin or whatever, get it running true with DTI & secure the chuck into that position. Same principle I have seen others use on ER-40 chuck/backplates.

Now this cant be as good as radial set screw systems (which are typically big $) because the front mount chuck could drift away and out of alignment, particularly under heavier cuts. But maybe because the typical turning operations in collet chucks are lighter duty, or maybe you can get away with it for longer on smaller HP lathes, not sure. But it allows for adjustments that are a whole lot easier than the alternatives. I'm considering doing an ER this winter so I'll let you know.

But ideally your workhorse 3J chuck should be quite solid to the spindle to allow heavier cutting & be as true as possible, particularly if you are re-gripping work & expecting some repeatable concentricity. Unfortunately that's where jaw regrinding/replacing comes into play if everything upstream of that is in good shape. I think back in the good old days, the chuck you were sold was probably ground on your lathe & that was that. Depending on the lathe style, the critical surface is the taper on the spindle nose. Its job its to make the chuck accessory concentric. The screw or camlock pins job is to axially retain it there. Where it gets interesting is on some machines the screw is expected to fulfill both roles. That has drawbacks. Not insurmountable, but you may require countermeasures.

 

[YYCHM]

GOOD GOD, look what I found between the chuck and the face plate!!!





Do you think that was there before I unbolted the chuck or settled there while unbolting the chuck?

Got to wonder now what's floating around inside the cuck.

 

[PeterT]

Am I interpreting your picture correct? Is this the recess in the back of the chuck supposed to fit (snugly) over the boss lip of the back plate? If so, its hard to image they could have even been mated that way with amount of swarf around the lip. Maybe most of it just came loose when dismantling & sprinkled down over the lip? Its common for swarf to work its way into the jaws & into spindle tube if you don'y clean it periodically. But I'm interested in that chuck mounting.

 

[YYCHM]

Yup, that's the registration boss and recess. It's not very deep.

 

[PeterT]

My chuck recess fits to like within 0.001" (OD to ID) so hard to imagine even the tiniest amount of swarf even fitting in there.

 

[YYCHM]

Ya, I didn't think that much stuff could have been between the chuck and the plate without the chuck being seriously out of wack. There is a pocket between the chuck and the spindle nose that must have been full of swarth. Once I have this mess cleaned up, I'll have it serious look at the registration boss. It doesn't look all that healthy upon first inspection.

Should probably flush out the chuck and lube it while I have it off to.

I found it interesting that the chuck bolts were metric (13 mm), is that to be expected?

 

[historicalarms]

Greg, from the photo it looks as thought there is a second "smaller dia."recess cut into the chuck back plate that would easily collect the scarf you are seeing and it be released from its holding spot when the bolts are loosened.

I tried "flushing my 3-jaw" a couple of times but gave up on the results and just disassembled it fully for a cleaning now. It can't be re-assembled incorrectly, it can only go back together as was originally manuf. so don't hesitate to take it apart. One pointer tho is to # mark each jaw and chuck tightening bolt and it's pocket with a marker in order that they can be removed from the body...will speed up reassembly, eliminating any 'trial & error".

edited for clarity: actually it can be reassembled in the wrong order but it wont damage anything if it is, it is easily spotted when the jaws work in wrong unison...hense the marking eliminates the trial & error.

 

[trlvn]

Should probably flush out the chuck and lube it while I have it off

We should all probably do that much more often than we do!

Craig

 

[YYCHM]

These screws aren't budging! Do I dare trying one of those manual impact drivers?



Ok... got her apart with the aid of an impact driver. She's pretty clean in there. No swarth that I can see.

Should I grease the internals or just oil them?