firbikrhd1
11-19-2011, 10:58 AM
I have a set of telescoping gauges made by a commanding American manufacturer that makes rules, wigglers and other small measuring tools. This set is about 35 years old. On several occasions I have tried to use the 1"- 1 1/4" gauge without success. It was unreliable in gripping the spring loaded "arms" and rough in it's operation. I had written this off to being something less than Starrett, however the other gauges in the set seemed to work OK.
Recently I needed to measure an ID of a hole for a close fit and hadn't gotten around to purchasing some new gauges. Of course the one I needed was the one that didn't work. With nothing to lose I decided to try to take it apart, find the problem and possibly fix it.
This being the first snap gauge I had ever dissected I proceeded carefully, first removing the setting knob and the internal long pin. Next, I gripped the body of the gauge in soft jaws of the vise, and, using a small adjustable wrench across the top of the "T", unscrewed the "T' from the body, being careful to collapse the spring loaded arms so as not to apply pressure to them and bend them. With the body off I found a tiny double ended pin that was broken and the hole in which it was suppose to go, offset in the "T" rather than centered. With the pin removed the spring loaded arms came out each end. The tiny pin engages a slot in each arm, normally, preventing them from being ejected by the spring. Now I had to figure out how to take the "T" apart in order to realign the hole. The "T" is two parts, a cylinder tapered on the outside like a tapered pin and the central holder which is internally tapered. I measured each end of the cylinder to figure out which way to press the cylinder and used a 1/8" brass pipe fitting as a receiver for the cylinder as I pressed it apart in the vise. I cleaned and deburred the sliding parts and pressed the cylinder back together with the hole centered in the threaded area of the tapered holder.
Next I turned a new double ended pin (visible for scale sitting on the penny in the picture). This is a tiny pin and I was concerned about turning it. The overall length is .185", diameter at the large end is .079" and the small end .040". This is the smallest part I have turned to date and it gave me no problems on my 10" Logan lathe using a cutoff tool and Diamond Toolholder. The material I used is unknown steel but I believe it to be hot rolled from the appearance of the exterior. Lastly, I reassembled the gauge in reverse order.
The gauge now works very well. I was able to accurately measure the hole which started me on this project with accuracy and the gauge will be ready next time I need it.
http://i283.photobucket.com/albums/kk287/firbikrhd1/PB180074Small.jpg
http://i283.photobucket.com/albums/kk287/firbikrhd1/PB180073Small.jpg
http://i283.photobucket.com/albums/kk287/firbikrhd1/PB180076Small.jpg
Recently I needed to measure an ID of a hole for a close fit and hadn't gotten around to purchasing some new gauges. Of course the one I needed was the one that didn't work. With nothing to lose I decided to try to take it apart, find the problem and possibly fix it.
This being the first snap gauge I had ever dissected I proceeded carefully, first removing the setting knob and the internal long pin. Next, I gripped the body of the gauge in soft jaws of the vise, and, using a small adjustable wrench across the top of the "T", unscrewed the "T' from the body, being careful to collapse the spring loaded arms so as not to apply pressure to them and bend them. With the body off I found a tiny double ended pin that was broken and the hole in which it was suppose to go, offset in the "T" rather than centered. With the pin removed the spring loaded arms came out each end. The tiny pin engages a slot in each arm, normally, preventing them from being ejected by the spring. Now I had to figure out how to take the "T" apart in order to realign the hole. The "T" is two parts, a cylinder tapered on the outside like a tapered pin and the central holder which is internally tapered. I measured each end of the cylinder to figure out which way to press the cylinder and used a 1/8" brass pipe fitting as a receiver for the cylinder as I pressed it apart in the vise. I cleaned and deburred the sliding parts and pressed the cylinder back together with the hole centered in the threaded area of the tapered holder.
Next I turned a new double ended pin (visible for scale sitting on the penny in the picture). This is a tiny pin and I was concerned about turning it. The overall length is .185", diameter at the large end is .079" and the small end .040". This is the smallest part I have turned to date and it gave me no problems on my 10" Logan lathe using a cutoff tool and Diamond Toolholder. The material I used is unknown steel but I believe it to be hot rolled from the appearance of the exterior. Lastly, I reassembled the gauge in reverse order.
The gauge now works very well. I was able to accurately measure the hole which started me on this project with accuracy and the gauge will be ready next time I need it.
http://i283.photobucket.com/albums/kk287/firbikrhd1/PB180074Small.jpg
http://i283.photobucket.com/albums/kk287/firbikrhd1/PB180073Small.jpg
http://i283.photobucket.com/albums/kk287/firbikrhd1/PB180076Small.jpg