Parallel Jaw Machinist Clamps

A basic tool for most machinists is a parallel jaw clamp in several sizes.  One of our earlier class projects was to fabricate a parallel jaw clamp.

The basic plans for these clamps came from  pages 149-153 of The Machinist"s Bedside Reader [first in a series] by Guy Lautard ISBN 0-9690980-2-2
The Guy's home page URL is
You can order the series of three readers from Guy's webpage or
These have also been on sale at several mail order mill supply outlets such as Enco and Harbor Freight [see handy links section for urls.]


The basic clamp as assigned:

Clamp was completely machined on a lathe including angle cutting of the jaws.  This was done using a faceplate and right angle plate.  Base stock was 1 inch X 1 inch CRS surfaced on all sided to 3/4 inch square.  Holes were drilled on the lathe using the faceplate.    7/16 X 20 threaded rod [Allthread® or Readythread®] grade 5 was sued for the screws.  Knobs were turned from 3/4 inch diameter CRS bar stock to 5/8 inch diameter, drilled and tapped for 7/16 X to threads, knurled and parted-off.  Knobs are "Loctited" on the threaded rods for retention.  


A some what fancier clamp with the corners rounded using a corner rounding end mill and acorn nuts to allow increased clamping force. These nuts are commercial items and were "Loctited" onto the shafts.


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last updated by GmcD on 19-Mar-11 19:30
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