Author Topic: Treated myself to some new parallels!  (Read 2655 times)

Offline Overbuilt and Overkill

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Re: Treated myself to some new parallels!
« Reply #15 on: July 07, 2023, 10:01:03 PM »
While I now have decent gauge blocks, I used a set of adjustable parallels as a stand in such as setting sine bars for quite a few years. So fwiw, normally there quite difficult to pre set to a high level of precision, but because of there design with the opposed slow tapers, and through some trial and error. There's a useful trick I've figured out to slowly creep up to a micrometer level of accuracy. Slightly tighten the locking screws just enough to still allow a fairly stiff movement of the two tapers, get your required height roughly set to a dial or digital caliper measurement but still slightly too short in height. Apparently my Starrett adjustable parallels aren't fully hardened, so as Mcgyver pointed out, you do need to be a bit gentle with them. I use a scrap piece of soft wood and then lightly tap either end of the parallel against it depending on if I want the parallel to increase or decrease in height. Again and because of those slow tapers, you can pretty easily adjust the parallels height to within a few 10ths or less and measuring with a micrometer in just a minute or two. Tighten the locking screws and double check the measurement in case there was any movement. Like anything else, it takes a few tries before you get a feel for how many times or how hard to tap against that wooden block verses how much actual height change you'll get. I highly doubt this method is anything new, but so far I've not seen it mentioned anywhere else. So maybe others will get some use out of this.


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