Need help to fix a broken DTI

[compact8]

My DTI has recently dropped onto the floor and I thought nothing was broken as it didn't exhibit anything abormal. I continued to use it until the dial is found to be loose today. The dial consists of an outer ring fitted to the hub which is fixed to the body with two bolts ( see picture 2 ) . I believe I need to remove the outer ring from the hub, re-tighten those two bolts and fit the ring back to the hub again. The problem is how to seperate the hub from the ring to get the heads of those two bolts exposed. Has anyone done this before ? The brandname of the DTI is Interapid, swiss made.

 

[stupoty]

I think i have the same make. It got damaged in the post , if no one comes up with how to dissaseble it I will pull mine apart and take photos.

Stu

 

[markba633csi]

I'm wondering why are there screws on the table in the first photo and in the dial in the second photo?? Are they not the same screws?

 

[atunguyd]

I would start by seeing if the glass (more likely perspex) lid snaps off. Once that is done you probably just need to remove the pointer and then the dial face. That should expose the the screw heads.

You may need the tools that watchmakers use.

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[Deleted member 69715]

The clear cover is cheap plastic. You can pry it out, but with age they can easily be damaged. Possibly use gentle heat (hair dryer could work) to ease it out. Remove pointer then the cover. That will expose the screws. By the way, those are not screw heads sticking up out of the body; they're positioning sleeves to maintain a proper mesh of the gears.
Get past the above, you get to enjoy "clocking" the dial so it will read in negative and positive travel of the tip correctly. I can guarantee you'll play with that for a bit.

 

[atunguyd]

Don't worry about damaging it. Your local watch supply shop can give you a replacement crystal that will fit. I have replaced the crystals in a dial vernier and two vintage starrett dti's with watch crystals.

What you actually need is a crystal lift. It squeezes the crystal just enough to lift it from the bezel (it is a press fit)

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[Mill Lee farm]

The two screws in question thread into the top of the case correct? How did they ‘come out’?
The case threading isn’t stripped now is it?

It looks like the case cover screws are out in your 1st photo. Not sure if they’re the same size/thread but if so, do they thread into the case ok?

I too will be opening up a pair of Brown & Sharpe DTI’s when I find the time…

 

[markba633csi]

I'm wondering if there was a pre-existing problem with the attachment of the dial to the body- even with a drop to the floor the dial wouldn't usually pop off like that
Careful prying around the bezel with an X-acto knife(s) will probably get it off- then the needle and dial need to be removed-carefully
Those are good units and worth trying to save

 

[extropic]

@compact8

Because that is a fine DTI and otherwise looks to be unabused, my first recommendation is to take/send it to a reputable instrument repair station.

If that's not your preference, I'll try to help you with some DIY information.

First, the crystal will need to be removed. The crystal is a friction fit (with dovetail) into the bezel. The only way I can think of removing it safely is to use a vacuum chuck. By 'vacuum' I mean a vacuum pump, not a shop-vac. The chuck would need to seal (O-ring) on the face of the crystal near the outside diameter and leave clearance, inside the chuck, so the pressure differential can flex the crystal into more of a domed shape. That will reduce the major diameter of the crystal and the bezel will fall away. Be aware that the crystal might be scratched or deformed if it is forced up against any hard surfaces, so guard against that when designing and fabricating your chuck.

Next you will need to pull the hand off of the pinion shaft. Below is a link that shows how to do that correctly.

How to Remove Watch Hands - Esslinger Watchmaker Supplies Blog

The procedure for removing watch hands is going to be the same for the majority of watches. This article will walk through the basics of watch hand removal. Some of the most common reasons for needing to remove watch hands are broken or damaged hands, changing the color or style of the hands and...

blog.esslinger.com

After the hand is removed, I think the face will be easy to remove and the screw heads will be revealed.

If you decide to DIY, please document your process here so we all may learn.

Good luck.

 

[extropic]

I'm wondering if there was a pre-existing problem with the attachment of the dial to the body- even with a drop to the floor the dial wouldn't usually pop off like that
Careful prying around the bezel with an X-acto knife(s) will probably get it off- then the needle and dial need to be removed-carefully
Those are good units and worth trying to save

Prying the crystal out with a knife blade will leave it in a condition roughly equivalent to smoothing the wrinkles out of you best suit by driving your 4x4 over it on a gravel road. It will be pretty ugly by the time you get done. The crystal has a larger OD, in the free state, than the ID of the bezel.
The crystal is installed by deforming it into a slight dome to reduce the OD. The bezel ID is slightly angled outward toward the bottom (conical dovetail) so the installed crystal expands into and is retained by the bezel.