Tell me about Trav-A-Dials

A friend gave me a like-new (possibly unused) Trav-A-Dial in exchange for some computer work yesterday. Anyone know about these things?

It's the usual black box with a dial. On the bottom is a dovetail rail. On top, centered next to the dial, is a large graduated knob. It looks different than the ones on the company site right now. Couldn't find a model number anywhere.

How're you supposed to mount these things? I didn't get any kind of mating dovetail fitting, although I did get a few screws an odd-shaped washers with it. Also, how free are they supposed to move? When I turn the wheel by hand it seems a little bumpy, like the lash is set tight. Dunno if this is intentional.

John, I've got one that I acquired 4 years ago used in a deal on other junk also. Put it on the shelf and sort of forgot about it because of other, higher priorities. Ran across it again the other week and noticed it now is sort of locked up, don't think it was that way when I got it! Guess I'll hose it down good with a penetrant oil.
I also ran across a manual reprint on e-bay and purchased that. If you want a copy, e-mail me a mailing address and I'll send you a copy if I can find it!
We had them on the lathes where I worked till we put on DROs, had to fab our own mounting brackets. I used them back when I was in the lathe section before the DROs and they were great for shoulder lengths and other critical maesurements in the "X" plane.
Dave

If you don't have both parts of the dovetail, it will be difficult to work correctly, IIRC.

I bought one not knowing, found that the bottom dovetail has cracked & is not tight...overuse I suppose.

There are some flat metal springs that hold the 2 parts of the dovetail together, IIRC.

I've rebuilt quite a few travadials, the parts are available from Southwest Industries and not terribly expensive, including crystals, foam seals, glue, dials and hands.

What usually goes wrong is that the foam seal is allowed to deteriorate and small chips get inside.

If you want to get it operating smoothly again you will need to disassemble it. To do that, you need to pop out the crystal, pull the hand and remove the dial, that exposes a screw head. There are also screws that either are obvious (i.e. visible on the top of the case), or are accessible from the back side by removing some shiny black sealant.

Internally, there aren't any adjustments, it is just a matter of cleaning. A scribe or fine point is useful to clean chips out of the gears. There are some really small ball bearings that take thrust for the pivot shafts that need to be cleaned thoroughly. I usually flush with wd-40, then hot water, wd-40 again, then put some lubriplate or a high quality spindle oil in the bearings, but leave the gears dry. Inspect the pivot shafts, esp. the one that the hand presses onto, for straightness.

New crystals are about $5 each, dials are $5 or $10 (you can get the dial that has graduations every .0005").

Sometimes the bezels are in really bad shape, and the groove that holds the crystal is damaged making fitting a new crystal difficult, but those are available as parts also.

There are several different models of travadial, and not all of the people who take orders are familiar with them all, so at times I have received the wrong parts, but when that has happened, I usually call and ask for someone who really knows the older models, explain the problem and he will usually drop ship the correct parts at no charge. For example, I received some crystals that looked like "jar lids", and were intended to press on to the outside of the bezel, but what I wanted were the original style. The first person I spoke to said the originals were not available, but after some persistence, they found some and sent them to me. They also may say no parts are available for certain models, but I've found that the parts they have will work or can easily be made to work.

-Dave

There have been a couple of threads on this and the Machine Parts Wanted boards of this forum about my search for the GB42 issue of the Trav-A-Dial. I had a couple of responses that included scans of instructions, and if the guys who sent them don't notice this thread, I'll be glad to forward the favor. I'll keep an eye on the thread.

Froggie

You might contact Pat Hager:

www.travadialrepair.com

Mike

Worthless, posssible radioactive. Send it to me and I will see to its safe disposal.