12" Digital Calipers Inch/Metric

[RickKrung]

I've been using a 6" digital caliper (inch/metric) for measuring and setting the knife jig projection, or using the caliper to set a marking gauge for the jig projection.  Works well because I can set it on metric and I don't have to do any conversions.

Not the case for things beyond 6".  I have Asian 12" dial caliper that I've been using to measure USB height, but the foot is not wide enough to reach the centerline of the USB, so I measure the USB height using an extended shaft marking gauge or set the USB height on the marking gauge and then use that set the USB height.  Because the dial caliper is only inch, I have to do the conversions.  PITA.  The marking gauges are what I call my "old reliables". 


I had been Jonesing for a 12" digital inch/metric caliper.  I recently found one I thought looked good, and so ordered it.  What caught my eye, however, when searching, is that it has available an extra wide foot attachment, which I thought would solve the problem of the caliper foot not reaching the centerline of the USB.  Shown are the 12" digital caliper with foot extension attached. 




The foot is set to zero by placing it on a known flat surface and securing it well.  It can be difficult because the 12" caliper is like a lever and it is difficult to get it all flat and tighten the screw at the same time. 


I can now measure the USB height directly, in metric, using the digital caliper, but I find it clumsy.


It is also better at setting the knife jig projection than when I could/would use the 6" digital caliper.  The foot extension does fit on the short caliper. 


I will know better after having used these for a while, but at this point, I believe I'll end up using the new 12" digital caliper for setting the marking gauges ("old reliables") and then using them to set projection distance and USB height. 

Rick

[Ken S]

Interesting and very informative post, Rick.

The Tormek really is a metric machine, and life is easier not having to convert measuring systems. Have you considered making a 100mm riser block to sit on the top of your Tormek? You could use a piece of stainless steel rod for the vertical piece. The rod would fit into a through drilled hole into a steel piece 3/4" squareby a couple inches long. (secured by a cross drilled Allen screw).

The other end of the square piece would be through drilled to a sliding fit over the threaded leg of the usb. This riser block could be fashioned several ways. This way would make it easily removable when using the Tormek for other purposes.

The key is the 100 mm height. That would let you use youe metric/English six inch digital caliper. Even an old guy like me can subtract 100 mm in my head. 

For consistency, I would mark a circle around the point of the T8 (or whatever model the reader is using). I would also initially and occasionally check the 100 mm to make sure the rod had not slipped.

Ken

ps When the Wright Brothers Cycle Shop was moved to Greenfield Village (part of the Henry Ford Museum near Detroit), there way an old wooden barrel next to the metal lathe. Everyone thought it was just a trash barrel, however, to preserve suthenticity, the barrel was moved also and again placed next to the lathe. No one knew how the original engine had been made on the lathe; the engine size exceeded the swing of the lathe. Eventually someone realized that the big piece of "scrap" steel was actually the riser block to increase the swing of the lathe. (Swing is the maximum diameter piece which can be turned on a lathe.)

Thank goodness for low tech thinkers........

[cbwx34]

Nice find.

The "foot attachment" reminded me of Jan's modifications that he made to a "Starrett square"...

https://forum.tormek.com/index.php?topic=2879.msg15575#msg15575

p.s.  You still need to mark your USB with measurements....



p.p.s  Then I saw this...



(Anyone else picture something like this attached to a USB?) 

[RickKrung]

What a great idea, Ken, the 100mm riser post.  Just about anyone can do it and it avoids the extra expense and trouble of obtaining and using the longer caliper.  There would be a number of ways to set it up.  I still like the extended foot and since it does fit on all three of my 6" calipers, which are all 16mm (5/8") wide, as is the 300mm (12") caliper, it is very handy for setting the jig projection and setting the USB height. 

Nice story about the lathe riser block.  Riser blocks are commonly used on machine tools.  I have a small knee mill and among its users, it is very common for a riser block to be put between the column and head to increase the working space between the quill and table. 

BTW, my grandfather was a patron of the Wright Bros. bicycle shop, as a boy.  He came home one day with a flat.  His mother sent him down to their shop to have it fixed.  When he came home, his mother asked him if he knew who they were. He did not, so she told him.  In 1972, when, as a college student, I went to Dayton to move my grandfather out of that same house, we came across a hand drawing of the flier and as I recall, it was signed.  Unfortunately, it "disappeared".  We think my father's "crazy sister" squirreled it away.

Rick