Bob tail caliper

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Rudy from Norway

Rudy from Norway

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How often doesn't your caliper bump into the machine somewhere because it is too long? And what do you do about it?
Wonder why I didn't do this the first day I got my machines. The first evening I had it in the shop I found my selves use it all the time. Most measurements we do are less than 50mm / 2".

Rudy

2017-12-19 18.58.24.jpg


2017-12-19 18.56.46.jpg


2017-12-19 18.55.31.jpg
 
Looks like a good idea though I wouldn't want to cut my expensive calipers. In fact, I once drilled 2 holes in a cheapo $5 Chinese set and it cost me 2 drill bits - those things are hard!
 
My calipers are not very expensive at around $30 from China, (But they are good). Got an extra for the purpose. Cut it on the grinder. There is no need for the support strap on the backside over the depth gauge rod. Because it's so short it stays in place. Othervise I would just wrap something around the end instead of drilling holes.

Rudy
 
You can buy a short caliper for less than $5 US on Banggood. It will be a carbon fiber composite and limited in accuracy but when you get that close to the desired size you probably should be using a micrometer for final measurement anyway.
 
Yes, you are right. However, looks like it doesn't have the depth gauge. And it's 4". Still too long to put upright in a small mill (which has limited purpose anyway without the depth gauge).
With the calipers I have, which is probably a copy of Mitutoyo? is actually very accurate and stable. I have a high quality micro, but I'm getting the same result with the caliper if I do a proper measurement (which is easier with the micro).
I wouldn’t necessarily cheap on the accuracy for a "Bob tail" caliper because I found my selves use it 90% of the time. Even if I could use the long one, the shorty was at hand and did the job 100%.
Typically the short one lay by the machine and the long one on the bench.
Works for me..

Rudy
 
Herbie, I actually got one. Bought it to measure tyre treads. When I look at mine I don't have the confidence in it to bring it into the shop doing 0,01mm measurement. 0,1mm is probably ok. And that is also ok for many applications. Wish there was one in metal.

Rudy

Tyre depth gauge.JPG
 
Rudy,

Your little cutoff jobs are in fact retailed around a few places (100mm, 4" ones) for little money, specifically for the sort of work you are doing with it.

BUT, if you have an old set with duff main jaws, you can, with a little grinding, easily turn them into a hi res set of 'Jenny' calipers, ideal for scribing a line parallel to an edge.


John

Precision oddlegs.jpg
 
I have a 4" digital caliper that I end up using lots more than my 6" one.
 
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