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Starrett combination square

spotcheem

Plastic
Joined
Dec 17, 2019
The vial level on my old combination square is broken. How do I get the screw holding it in place out, and where do I get a replacement vial? I appreciate any help. The original was glass. I also need a source for the scriber as well as the level vial. Thanks!
 
Since new Starrett are so expensive, when I'd see a level or square with a broken vial, I'd pick it up for a buck or two. The intention was to repair several at once. Much as I hate to admit defeat, they're all still in the junk box.

Turns out, sending them to Starrett Repair Service is barely cost-effective against the price of a used unit. Buying the vial and repairing them oneself is only a good deal if one enjoys a challenging hobby. Takes hours of time and care to do it right.

jack vines
 
The vial level on my old combination square is broken. How do I get the screw holding it in place out, and where do I get a replacement vial? I appreciate any help. The original was glass. I also need a source for the scriber as well as the level vial. Thanks!

Are you sure it's a screw and not a pressed in plug?
 
Are you sure it's a screw and not a pressed in plug?

Looking at my 80's vintage Starret combo squares (6" + 12"), it does appear to be a plug like maybe the vial is slightly pressed in? Or maybe the plug is just covering a set screw, dunno...
 
I have replaced vials in carpenter levels but not in a combination square. I inherited Starrett combination squares. I'm a retired carpenter and used combination squares often. I do not recall ever using the level vial or the scriber. Try a scriber from a piece of junk square , probably will work.
When I replaced the vial in a Hybridge level I set it in Plaster of Paris.
Usually not worth the effort but this is a top quality level. Took 2 hours before I got the vial in and set in Plaster of Paris.
 
I don’t know how to post photos, anyone know how? And is posting photos allowed?
I’m kind of new to this forum.
There is a screw or plug at the base with a slot. But I don’t know if it is a screw or just a pressed in plug. Wish I knew how to post photos....
I did contact Starrett a while ago and they do repairs. Expensive! I just thought if I could get the screw out, and find a vial, I could do it myself for the satisfaction.
 
I have a few Starrett combination squares. And I have ordered replacement scribers. Each one has been a bit too small. I need a way to very slightly increase the apparent size of the scribers (by definition harder than the gates of Hades). Ideas?
 
What is your procedure to calibrate the level vial once you put it in , to the edge of the square? And then how do you maintain its position while you put in plaster of paris? seems tricky?!
 
Spotcheem --

Bent-glass vials are commonly, if not usually, bedded in plaster (or today, RTV). The plaster or RTV is put in place first, and then the vial is pushed into the bedding. The vial is adjusted by pushing the high end deeper into its bedding compound. As you might suspect, such adjustments are highly iterative.

In a production environment, vial adjustments were usually done with the stock, or body, of the level instrument on a known-to-be-level surface.

John
 
Most have a brass sleeve in the hole where the scriber goes. Either replace the worn out sleeve, or add a new brass shim stock sleeve.
 
In a production environment, vial adjustments were usually done with the stock, or body, of the level instrument on a known-to-be-level surface.John

I found this info useful. IMHO, plaster is a little bit easier to replace I think - hard to scrape broken glass and cured RTV out of a small hole if the vial breaks again. BTW, in a nonproduction environment you can do what is called "bucking the level". Get a surface that's pretty close to level. Don't bother leveling it unless that's really easy. But you can test a new vial in wet plaster using the surface. Note how far out of level it indicates. Then reverse the level and compare. Adjust to cut the difference in half. Switch the level back and check. For the level in a combisquare, though, it may just be easier to level your surface plate with wedges or some such (bucking is often done with the ultraprecision levels).
 
I found this info useful. IMHO, plaster is a little bit easier to replace I think - hard to scrape broken glass and cured RTV out of a small hole if the vial breaks again. BTW, in a nonproduction environment you can do what is called "bucking the level". Get a surface that's pretty close to level. Don't bother leveling it unless that's really easy. But you can test a new vial in wet plaster using the surface. Note how far out of level it indicates. Then reverse the level and compare. Adjust to cut the difference in half. Switch the level back and check. For the level in a combisquare, though, it may just be easier to level your surface plate with wedges or some such (bucking is often done with the ultraprecision levels).

Still don’t know how to get the screw/ plug out.
Still don’t know where to buy a replacement vial level.
Still don’t know how to post photos.
Help!
 
I have replaced a few broken or missing vials, but they were all on (IMO) low accuracy tools like combination square heads, so i wasn't too concerned about how precise they seated. If the bubble was reasonably centered when it sat on a level surface, I was happy. One was an old Starrett that was missing the vial. It may have had a plug originally, but I just packed the end with plaster-of-paris much like John Garner described since the other combination square I was fixing at the time (a Miller Falls) was done that way.

IMO the design of how the vial is held says a lot for how much accuracy you can expect from it. If the vial is directly adhered to the frame of the tool, it's for reference alone. If the vial has some means of mechanical adjustment or is in a separate tube attached to the tool, then you can worry about how many tenths it will read to.

One I still need to fix is a Brown and Sharpe combination square. It has an aluminum plug in the end and when I get to it, my plan is to drill it out and turn a new plug to take it's place. It's old vial was set in some kind of rubber'y material like RTV. I don't think what you use is quite as important as long as it dries solid and provides a pastel background to make the bubble more visible. Plaster is easy to use and cleans easily when dry if it seeps out around the viewing area.

As far as where to get the vials, most of mine were new-old-stock on Ebay. I've been known to scavenge them out of trashed tools as well. For general reference use, all you need to worry about is that the length and diameter match the hole you want to set it in.
 
Posting images? Here you go.

https://www.practicalmachinist.com/...sing-boards-image-hosting-350499/#post3176881



I don’t know how to post photos, anyone know how? And is posting photos allowed?
I’m kind of new to this forum.
There is a screw or plug at the base with a slot. But I don’t know if it is a screw or just a pressed in plug. Wish I knew how to post photos....
I did contact Starrett a while ago and they do repairs. Expensive! I just thought if I could get the screw out, and find a vial, I could do it myself for the satisfaction.
 
Happened to see a video from “How Its Made” with regard to Starrett combo squares. The cover for the vial is a metal plug that is pressed into the bore. A drill and pry procedure will probably work.
Joe
 








 
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