10ee quick change gearbox problems - how to value?

How much should you subtract from the purchase price when the inspection reveals missing teeth on quick change gears? What if a donor gearbox is available (condition unknown)?

I have remotely negotiated a price on the purchase of a '51 that is assumed to be in working condition, but is unpowered. After that, a kind soul did a quick inspection of the machine. In his checking three gears, he found one with missing teeth - maybe a few teeth based on the period of non-rotation.

Inspecting the machine is 6.5 hours one way, but my destination if picking up is 2.5 hours. I will check all of the gears - if I go look at the machine. I am diving into the archives to understand what will be involved in a proper repair - I don't know yet. I may have a parts machine available.

Also, given this discovery, what other assumptions and pre-purchase checks should apply? Is it possible to fish a magnet around in there? Should/could I take a sample from the bottom with a turkey baster and hose? Visually checking the gears for debris related nicks and chips seems mandatory, but I'm not sure how much I'll be able to see.

I look forward to a restoration project in the future, but not near future.

Thank you.

Gernoff's excellent thread on rebuilding the gearbox suggests a fix for this is a much bigger effort than I would have imagined.

http://www.practicalmachinist.com/v...are-dial-quick-change-gearbox-rebuild-269296/

I suggest keep looking.

That machine isn't for someone on the hunt for a good 10EE. Getting into the gearbox is not a trivial matter and those parts are like finding hen's teeth. There are good machines out there for the picking, move on from that one.

DaveE907 said:

That machine isn't for someone on the hunt for a good 10EE.

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Thanks, Dave. I cannot argue with that sound advice. I may yet go look at the machine - if only to expand my knowledge of 10ee assessment, wear measurement, and diagnostics.

My limited info on the gear train suggests problems confined to the QCGB are not as bad - but if the gears in the headstock are involved, then it is much more serious and the spindle must be removed, etc. Exactly how to categorize various symptoms is something I am still trying to understand.

I'm still not up to speed on what is involved in 'merely' changing gears in a square dial QCGB.

Just to address the OP's original query, I would suggest that you assess a good price on the lathe, then reduce the bid by 50% to account for the QC box repair. Regards, Clark

Glug said:

Thanks, Dave. I cannot argue with that sound advice. I may yet go look at the machine - if only to expand my knowledge of 10ee assessment, wear measurement, and diagnostics.

My limited info on the gear train suggests problems confined to the QCGB are not as bad - but if the gears in the headstock are involved, then it is much more serious and the spindle must be removed, etc. Exactly how to categorize various symptoms is something I am still trying to understand.

I'm still not up to speed on what is involved in 'merely' changing gears in a square dial QCGB.

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Have to agree with Dave. Problem is not just that of taking on an avoidable 'opportunity' ("there are no 'problems'..")

One also has to wonder just what sort of profanity was visited on a 10EE to break them in the FIRST place. Failure is not at all common, so... run, do not walk...to a better starting-point.

Bill

Good news - my local inspector revisited this machine and was unable to reproduce the suspected threading gear problem! He thinks the original problem was due to not having the selector fully engaged, possibly due to gummy detents, lack of time, etc.

Based on that I drove down yesterday and took a look. I did not have nearly enough time to fully inspect the machine. Wear on the ways was minimal - less than .001" measured along the front flat way.

Question - when testing threading gears by manually rotating the spindle, I found a lot of backlash/slop when I would turn the leadscrew with my hand. Maybe 3/4 of a rotation, or so. Is that normal? What is the source?

Glug said:

Question - when testing threading gears by manually rotating the spindle, I found a lot of backlash/slop when I would turn the leadscrew with my hand. Maybe 3/4 of a rotation, or so. Is that normal? What is the source?

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Just played with mine - it's got maybe a 1/6 of a turn when the threading is set for 64tpi, a lot less when set for 8tpi. I'm not sure what would cause 3/4 of the turn in the spindle to take up gear train slack in a gearbox in good condition.

All that said there's noting in the gearbox that can't be fixed. I'd use the issue to get a decent price.

Glug said:

Good news - my local inspector revisited this machine and was unable to reproduce the suspected threading gear problem! He thinks the original problem was due to not having the selector fully engaged, possibly due to gummy detents, lack of time, etc.

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..and it also being less intuitive, harder for a noob to get right than simpler gearboxes. So, yes, good news indeed.

Based on that I drove down yesterday and took a look. I did not have nearly enough time to fully inspect the machine. Wear on the ways was minimal - less than .001" measured along the front flat way.

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Tells ME nada. 'Bout all that front ledge sees is uneven dirt & fossilized way lube build-up underneath and very modest wear from the roller bearings that keep the carriage from lifting if/as/when cutting in reverse. Otherwise it is mostly used for clamping-on depth stops and such.

IOW - the 'front flat way' isn't where one looks for wear.

The rear-face of the front prismatic vee-way is. Also the clearance between the underside of the carriage and the INNERMOST of the front flat ways. Not a critical dimension, either. So long as it dasn't yet TOUCH and 'unload' the front vee-way.

Even so, the bed is not ordinarily demanding of re-grind until that touches AND the front vee way gets both deeply worn AND considerably deeper at (usually) the HS end.

A 10EE has around four or more times as much bearing area as 'ordinary' lathes to begin with. It's carriage, including the 'wings' is actually longer than the 20" it traverses. Go and find a foto online of a 'Precision Matthews' lathe, sometime-darling of budding Gunsmiths. Look at how narrow the carriage is. That buys greater traverse for the bed length, but at the price of faster wear and MUCH greater susceptibility to rocking movement AS it wears. Or even before it wears. None of the 'Grand Old' high-end lathes (Monarch, Hendey, ATW, L&S, Axelson, the 'real-not-Regal' LeBlonds, etc.) have narrow carriages. Quite the reverse.

And a 10EE carriage is HEAVY, considering its compound and ordinary tooling are no larger than a modest SB ten or Logan..so it takes a good deal of cutting force to rock it.

Even when there is enough wear for it to 'rock' longitudinally and/or diagonally, the movement is constrained by the longer lever-arm of its great length in the first place. Such excursion as there is, then being divided BY said length so that the tool-tip moves less in response to the wear than on lesser lathes. MUCH less. Roughing cut, boring bar hung out? Yes. Finish cut, tool nearly centered over the cross? Probably not by enough to notice.

Question - when testing threading gears by manually rotating the spindle, I found a lot of backlash/slop when I would turn the leadscrew with my hand. Maybe 3/4 of a rotation, or so. Is that normal? What is the source?

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Stand by a minute whilst I find somethin' to put on my bare feet...

....

Well - the leadscrew on my September of 1942 'round dial' - a 'virgin' by no means - has mebbe ten-degrees or so of rotational free play in that situation.

If I had to guess... not all of the various and sundry players amongst the threading selectors were fully engaged.

Bill

Just throwing out speculation here, the lost motion in the leadscrew could be caused by...splitting the lead, worn half nuts, problem in half-nut closure mechanism, loss of thrust bearing in the leadscrew itself. I'd turn the actual leadscrew by hand, as far as you can get it to go in either direction, with "threading" engaged. If there is lost motion in that side of the 'train I would look carefully at the advice from above, some lever is not fully detented into position. If the rotational part seems solid, then most likely a problem on the carriage end.

Monarchist said:

Tells ME nada. 'Bout all that front ledge sees is uneven dirt & fossilized way lube build-up underneath and very modest wear from the roller bearings that keep the carriage from lifting if/as/when cutting in reverse. Otherwise it is mostly used for clamping-on depth stops and such.

IOW - the 'front flat way' isn't where one looks for wear.

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My reading suggested it was a good measure. I set up a mag base on the saddle and measured on the clean flat way. On another EE I found 2.5 to 2.7 thou of drop. You could also feel that zone when cranking the carriage. When I put a straight edge perpendicular to the V face, I could see light under the gap from wear. I suppose I should have measured that face with the TI.

Doing the fingernail 'test' on the inside of the front V way, I found it quite smooth and lacking scoring and ridging.

Other suggestions on wear measurement techniques are appreciated.

Well - the leadscrew on my September of 1942 'round dial' - a 'virgin' by no means - has mebbe ten-degrees or so of rotational free play in that situation.

If I had to guess... not all of the various and sundry players amongst the threading selectors were fully engaged.

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Thanks to everyone who checked out what is normal. The halfnut was not engaged when I did this. Clearly I need to do another hour or two of inspection. I need a mentor who is willing to answer questions like this when I'm in the thick of it.

The backgear engagement lever locking knob was also missing the retaining pin. So I was not able to engage the backgear and test it for basic function. I know that is sometimes intentionally done to prevent use of a broken feature, so I need to do a temp fix and check that out.

Someone recently posted an idea similar to one I had for unpowered machines - use a power tool to turn the spindle and check for NVH and other issues. I need to explore a way to do that.

Glug said:

My reading suggested it was a good measure.

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Not bad atall. Way you wrote it originally. I had visions of you walking an ignorant micrometer down the ledge at intervals checking its thickness..



You might now want to take a look at deciding whether to just up and BUY this Ole Girl before someone else takes advantage of your inspection work and beats you to it..

Bill

The backgear engagement is a simple lever that has a rod for linkage to the rod on the gearbox. The simplest fix is just to bring an uncut taper pin with you the next time you visit, and tap it in place. Next easiest would be to remove both headstock end covers and engage the linkage manually by pushing the 2-speed gearbox rod down or up.

Re: the play in the spindle, are you sure that all the gears were correctly set? The knob on the headstock set for threading, not feed, and all three knobs on the gearbox actually engaged correctly and all the way home? I've had friends with 10EEs tell me they had gearbox problems and the real problem was they did not understand how to engage all of the gears. It is easy to hit a "false stop" with some of the knobs if you don't rotate the spindle by hand as you engage the knob.

-Dave