# 2 Chas Parker Jaw Fitting

Just wrapped up building 96 pairs of Wilton, Rock Island, and Reed 3C jaws.  I am already low on 14 other pairs, but I wanted to fit a set of Parker jaws to my 956 vise.  What I learned in this round of fitting is that the Parker company really did not have a sure fire setup for building these jaws.

Cha Parker # 202-3 Jaws (9)Each vise is stamped with a number on both the Static and Dynamic jaws supports.  Then each jaw has the same stamped number, so during heat treating the fitted jaws should end up back where they belong.  The 3″ jaws shown have the number 96 stamped very closely to each other.  The other set is stamped the same number 96 but with a large gap between the 9 and 6. Clearly the assembler would know where the jaws belong.

Another issue I found is that the face of the static and dynamic jaws are not parallel.  This is why you see some Parker jaws with the faces hand serrated by a file.  They filed the serrations  because the jaw faces were resurfaced smooth for custom alignment and then the serrations were hand filed. The set of 4″ jaws I measured shows a .044 difference that has to be made up on the jaw faces, I believe this adjustment was made in the final fitting.

Drawing of unparalleled faces

Drawing of unparalleled faces

I cut the serrations on the jaw blocks when they are square, and I feel confident Parker did too on some of their jaws.  Parker used a shaper, while I used a CNC with a double angled cutter.Dressing angle on wheel This is why I have to custom fit each jaw to each Parker vise. Next, I fit the jaws with my surface grinder.  I dress an angle on the face of my wheel.  The 6″ jaws take a 12.96 degree angle. Then I set the jaws in a Wilton 7″ sine vise and set it to 12.96 degrees. The wheel is relieved on the back side so I can use the back of the wheel to grind the jaw flat and square.

Finish grinding in the two angles.

Finish grinding in the two angles.

I found all of these numbers with the microscope and setting points on my cad program. Then, after I got close to the width of the slot,  I started slowing down for the final fits.

Here is where I found  trouble. The jaw inserts I used for gathering my numbers and creating the points only got me close. When I was at a point to check the squareness of the serrated faces I found my angles were off.  And not by a little either. First real numbersI was off by .09.  This means I have to redress a new angle on the wheel and reset the sine vise, but at least I will know my final correct angles. The rest is easy, and by taking my time, making sure the static and dynamic jaws supports are filed and stoned flat, the finishing fit is just minutes away. Next is cutting the top radius and pinning the jaws to the Static and Dynamic jaw supports. I will cover this in the last blog on these Parker Jaws.956 Parker final fit (2)956 Parker final fit (1)

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2 thoughts on “# 2 Chas Parker Jaw Fitting

  1. Excellent Work! My 974G… yes, I said G. The Sticker from the factory is still there. It doesn’t open or close with out assistance…The main screw or worm gear seems fine, like new. I don’t know what I did. I Haven’t used it in many years… It’s in mint condition. Well ya know what I mean, any idea’s for a want a be enthusiast would be appreciated.

    • Hi Jason
      If you can un screw the spindle and remove it after removing the collar and your dynamic jaw support can not be pulled out then it sounds like it is rusted in place. If frozen then the two choices I would use is 1) Heat from a torch. Heat the Static jaw support all around the square slider, remember heat will expand cast steel and possibly break the seal. I like to stand a vise either up or down and add automatic transmission fluid in the slide area while heating and watch the oil seep into the crack. I know you have good paint on your vise but the vise is no good if it is frozen. 2) Second choice is putting the vise in a bucket of diesel fuel and let it sit for a couple weeks then use a hardwood block and see if it moves with a 5 lb sledge. There is other options but I have found these two options to work in very old and stuck vises. Good luck

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