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NeilS
22nd May 2010, 02:48 PM
I've been using these (slightly) modified calipers for some time and have found them to work quite well.

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They were originally this (http://www.cws.au.com/shop/item/305mm-internal-external-calipers) design and I reversed one leg which I found worked better on getting into deeper and larger bowls. Also reduced the width at the end of the straighter arm so that it could slip under the jaws of the chuck to measure the depth of the base. The rubber band (a braid covered hair band) acts like a return spring that allows for quicker and one handed operation.

Only downside is the depth of reach, about 9", which falls short of what I need on larger bowls or more sculptural forms. 12" reach would be better. I could make some larger ones myself but would prefer to buy some, metal work not being my thing. Does anyone know of a source of some larger ones of this type of caliper?

The Kelton large calipers (http://www.woodturnerscatalog.com/store/Measuring___Calipers___Kelton_Caliper___kelton_caliper?Args=) look like an option, but none of the Australian McNaughton suppliers seem to list them. Also, not sure I like a measuring scale instead of actual distance as is the case with the above style.

While on calipers, I recently unearthed this set of measuring cards (5cm to 20cm) that I used back when I was doing production pottery (used when making precisely fitting lids).

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Anyway, I idly thought I might be able to make some use of them somehow in the woodturning workshop. Didn't take me long to start to find uses for them until I now reach for them as much or as often as my spring bow or vernier calipers. Not sure I would have thought it worthwhile to take time out to make a set, but having them already is proving a boon. One downside of this set is the clear plastic... they literally can't be seen if they fall down on the shavings. Something more opaque would work better. I've just remembered that something similar came with an early Woodfast chuck for matching tenons and recesses to the jaws.... an old idea, recycled.


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rsser
23rd May 2010, 06:59 AM
Neil, I got my Kelton caliper from The Wood Works Book & Tool Co. - The Wood Works Book & Tool Co. (http://www.thewoodworks.com.au) I see he no longer lists them as you've discovered. The manufacturing quality was pretty ordinary at the time; may have improved since.

Ed Reiss
23rd May 2010, 11:40 AM
Just a thought Neil...spray paint the clear plastic set.

NeilS
23rd May 2010, 12:08 PM
In case someone else is looking for a larger set of double ended calipers with at least a 12" depth, the only ones I have been able to locate are these (http://www.mannyswoodworking.com/12indoeninca.html) in the US, for US$28. A reasonable price, but the shipping may add considerably to that.

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NeilS
23rd May 2010, 12:10 PM
Just a thought Neil...spray paint the clear plastic set.

Good thought, Ed.


Neil, I got my Kelton caliper from The Wood Works Book & Tool Co. - The Wood Works Book & Tool Co. (http://www.thewoodworks.com.au) I see he no longer lists them as you've discovered. The manufacturing quality was pretty ordinary at the time; may have improved since.

Thanks Ern

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Frank&Earnest
23rd May 2010, 12:55 PM
In case someone else is looking for a larger set of double ended calipers with at least a 12" depth, the only ones I have been able to locate are these (http://www.mannyswoodworking.com/12indoeninca.html) in the US, for US$28. A reasonable price, but the shipping may add considerably to that.

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I was thinking about making them myself (your modified design appeals more to me)but if you buy two we could split the shipping.

rsser
23rd May 2010, 05:07 PM
Yeah, I wonder how sheet acrylic would go for a DIY job.

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Your dimensioning cards Neil remind me of the scratch boards turners make up for repetition work; thin stock with brads tapped in at the key dimensions, and the heads nipped off.

NeilS
24th May 2010, 10:21 PM
Yeah, I wonder how sheet acrylic would go for a DIY job.

Good thought, Ern. Certainly easier for me to work than metal. Only downside could be the risk of snapping... I'm always dropping things.

Your dimensioning cards Neil remind me of the scratch boards turners make up for repetition work; thin stock with brads tapped in at the key dimensions, and the heads nipped off.

Yep, but the advantage of the scratch boards is that they both measure and mark. My cards don't have that benefit, they just measure. The marking ability of spring bow and vernier calipers is the reason they have been my preferred dimensioning tools for dovetails and the like. The downside is the time it takes to adjust them backwards and forwards to mark the different jaw sizes (last count was 12 jaw sets), although I have fixed some of my calipers at the most commonly used sizes.

If I didn't have my old pottery cards to hand and really needed a set of fixed size dimensioners I would definitely go for the scratch style.

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