a note on trav-a-dial repairs

thanks to the good offices of one of the NG denizens, I acquired a couple of
sick trav-a-dials. both were sticky. hee is a quick summary of an overhaul
procedure:
1.submerge up to dial in rubbing alcohol, move wheel occasionally, wait a
while see if it gets fixed (this will work if what is wrong is sticky oil
that was the problem with one of them)
2. remove crystal - I used an xacto knife to pry the crystal up from it's
bezel - others have suggested a suction cup
2. submerge in rubbing alcohol, wait a while and the dial will separate from
teh glue (it worked for me)
4. use diagonal cutters to gently lift the pointer off of the shaft and
remove dial. remove knob using allen wrench.
5. remove 6 flathead screws (2 under dial), open the thing up
6. clean carefully - spray brake cleaner is helpful here
7. remove all swarf from the gear teeth. do it again, you missed some, and
again, you still missed some - inspect with jeweler's loup - oops, still
miessed some, repeat again
8. to reassemble, rotate nylon gear on top of the steel wheel
counterclockwise until the hole in the gear lines up with a hole in the gear
below. put a 1 inch piece of stiff wire in the hole and put this aside.
9. oil the 6 ball bearings with clock oil. put a little oil on the gears.
inspect again for swarf - and remove what you rind.
10 reassemble, with the stiff wire still in place - the wire goes through a
hole that is pre-drilled in the top face of the unit
11. as you put the back (bottom) half in place, carefully align the shafts
until it snaps into place
12. reinstall 6 flathead screws (assembling the under dial stuff of course).
Oops, dont' forget the brass spring pieces that go on either side of the
drive wheel to press the seal against the surface the wleel runs on.
13 remove the stiff wire by pulling it straight out.
14. test for smoothness. if ti's rough, you missed some swarf, go back to
step 6. if it's smooth,
15 reinstall dial, use a weak glue to hold it in place, put pointer back
onto shaft, press on lightly
16. retest, if all is well, put the crystal back in place
Reply to
william_b_noble
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I sprayed wd40 around the wheel of mine a few times to loosen up whatever was sticking. Seems to work well now, but I have not mounted it to the lathe yet.
Reply to
Chuck Sherwood
Your method of taking apart the thing is good. I pried, gently, at the dial face and used alcohol too. However, I then took all the gears out and went over the teeth with a loupe' to see which teeth had stuff in them. I did not want to open the thing up again. The anti-backlash gears are what is being wound up that the wire holds in place during assembly. This is very important to make sure that there is no backlash in the measurement. I also turned the wheel before gluing on the face again to make sure no dirt had been missed. Thanks for posting. Eric
Reply to
Eric R Snow
Seems like a gentle blast of clean compressed air might have helped clean those gear teeth! - GWE
Eric R Snow wrote:
Reply to
Grant Erwin
Yep! Certainly a whole lot better than gumming them up with WD-40. Puke!
Bob Swinney
Reply to
Robert Swinney
I don't have one of these, but thanks a bunch for a very informative post - 'cuz we all know that sometime in the not-too-distant future - I will be owning one (just because I don't currently own one and this is a "rule") and we all know it's gonna need cleaned up Ken.
Reply to
Ken Sterling
no, it wouldn't have worked - on almost all gears there were pieces of swarf embedded hard enough that I had to really push wth the Xacto knife to get them to snap out. Air, and untrasonic agitation of a solvent would have helped get the cleanup started, but I didn't feel like setting up my ultrasonic tank or firing up the compressor. but, the manual cleaning of the teeth would be needed anyway.
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Reply to
william_b_noble

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