paul
Member
Posts: 8
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Post by paul on Mar 16, 2007 20:39:53 GMT
I bought some odd-leg calipers a week back but only had occasion to use them today. Although I bought them from Chronos they have the appearance of being quite crudely made though they were very inexpensive (look east!).
Trying to set them to a scribed mark and then using them to scribe a line parallel to the edge of the part is rather random though as the foot is rounded and uneven. Setting them to a particular dimension on a steel rule is almost impossible as they won't butt up against the end of it (it slips below th curved foot).
I have seen some that have a right angle profile cut in the foot which will rest on the edge of the workpiece. Would it be worth cutting such a profile into the leg or should they really just be used for finding a centre line?
TIA
Paul
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Post by alanstepney on Mar 16, 2007 21:29:37 GMT
Yes, it is worth carving a notch in them, plus smoothing off the profile will help too.
Once you get used to using them you will find they are, well, useful.
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Post by Steve M. W on Mar 16, 2007 21:40:04 GMT
Put the square profile in (check the profile at night school) they do work and are well worth getting used to.
Steve
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paul
Member
Posts: 8
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Post by paul on Mar 17, 2007 11:02:34 GMT
Ta chaps, will do.
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Post by standardsteam on Mar 26, 2007 8:40:31 GMT
I have a pair of the very same. I wondered how on earth I was going to scribe a parallel line or anything else with that odd shaped round end on the non-pointy leg. I did think of attacking it with a file to get a decent reference leg.
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Post by Tel on Mar 26, 2007 11:06:34 GMT
Yep, I also have a pair, bought some years ago, the use of which I thought must have been some 'black art' - the notch idea is worth tryin', then they might get more use than just stirrin' coffee.
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paul
Member
Posts: 8
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Post by paul on Mar 26, 2007 21:17:35 GMT
Here's what I did (copying the profile from a pair in a school metalwork class - thanks to Steve M W):  I also had to chop off some of the scriber to enable them to close up more. The minimum dimension they can be set to is about 4mm (er wassat... 1/6"). They are bloody useful now - used 'em lots already. |
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Post by Deleted on Mar 27, 2007 7:48:30 GMT
I bought a pair of these of a tool stall in the local market just a few weeks ago for £1 as one of those "might be useful one day" kind of purchases.
When I find them again from under the workshop clutter I will modify them as suggested, seems they will be far more useful and easier to use.
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Post by GeorgeRay on Mar 28, 2007 20:17:24 GMT
Back in the old days some 40 years ago when I was a young apprentice in the trog shop one of the things we had to make was a pair of odd leg calipers. Guess what shape the leg had to be, yes, with a notch in it just like the picture from Paul, because that was the way to transfer accurate measurements our instructor told us.  |
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Post by steammadman on Mar 28, 2007 20:36:51 GMT
Gthe same tool myself,made at doncaster in about 1952
don,t use em much these days,but they hang on a nail in the
workshop, just in case of need, along with a few other tools
and "gizzmoes" made in those far off days.
We used to grumble like hell at the time,thinking we were
wasting valuable learning time making those , ? , tools
which we had to polish to a fine finnish,oil and keep in the toolbox
we had to make also,as time went on, the box got heavier , some
of us put wheels on , and got another roasting from "OLD MACK".
happy days, but we didn't think that at the time.
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paul
Member
Posts: 8
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Post by paul on Mar 28, 2007 20:43:27 GMT
Does anyone know why they are called 'jenny' calipers? I know jenny is used for female donkeys and wrens but I don't think either of those are the source. I just googled and found a US architect named Jenny who built the first steel-framed skyscraper.....
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