Pipe Jaw Building

Making pipe jaws were a challenge in the beginning. I wanted to support the old vises by making these jaws since you can’t find any new ones very easily. My first issue was how the heck do you measure them. I wanted to build these as close to originals as possible since some customers want to replace only one.

Back in my mold making days I had to figure out how to measure shapes that were curved and needed it very accurate. I did this with a microscope attached to my CNC. I like the Skoal scope shown in my picture, which is very affordable.


I used the readout on my CNC to create points at every intersection.  On this drawing of a Starrett 326 Pipe Jaw, I added small circles at every intersection where it is easy to connect the dots.starrett_326_pipe_jaws

After squaring up the A2 Tool Steel blocks, I rough in the large and small V section where the teeth go, as with this CO Wilton Pipe Jaw. I do this so when I cut the teeth so I am not removing too much material.  It keeps the cutters corners sharp.


After carefully looking at the geometry created taken with the microscope, it became clear the teeth were rotated at 14 degrees and the teeth are cut at 90 degrees. The vise companies had special cutters made to cut the teeth at one swoop but I cannot afford to have a cutter of this size made or have room for a machine to handle this horizontal cut. Instead I made a special set of jaws to hold the pipe jaw at 14 degrees and use the corner of a 3/8 end mill and step down each cut.

Before I could do that, I needed the geometry and depth numbers so I could program my CNC. Here is a drawing I used for a American Scale Pipe Jaws. Looks more complicated than it really is.a-scale_pipe_jaws

As you can see in the drawing above, I color coded the geometry to help me in programming. After that, I pick up the pipe jaw noted here. When rotating blocks at a angle it becomes more difficult to locate the block. It is helpful to use a 1/2 inch gauge pin held on with a flat magnet and sweep in the pin center with a test indicator. I rotate the indicator 180 degrees then drop the indicator to hit the high point of the pin and rotate the indicator to  find the high spot, set the dial to zero and do the same 180 degrees on the other side of the pin till I have reached a zero reading finding the pin center. You could use a edge finder but I choose an indicator.

I also set the end mill to the top of the pin and that would be my Z-zero. All the numbers on the drawing are taken from the pin center line in the X axis (left to right) and the depth of the cut (Z-axis) is taken from the top of the pin.


After programming my CNC,  the rest is easy. Using a sharp carbide end mill I cut a roughing cut leaving .005 on the X-axis and .005 on the Z-axis, and then do a finish cut.


De-burr the entire jaw.  Send to heat treating and harden to 54/56 Rockwell.  Done.


Swivel Jaw Taper Pins: Removal, Sizing and Fabrication

If you are thinking about buying a swivel jaw vise without the pin, or one that is damaged beyond repair, it really shouldn’t be a deal killer. Swivel jaw vises use a pin that is tapered, and the pin should fit tightly and not wiggle or rock.  If the pin is kept clean, oiled and taken out every now and then,  you will never have a problem.  That said, removing these pins after years of not being used is some times difficult!

See the swivel pin all smashed in this 7" Prentiss

Hard to see the swivel pin all smashed in this 7″ Prentiss Vise.


I have had several that were really stuck, and making a Jack Screw is a great starting point. I use a coupling nut with two bolts which is as good as a simple compact jack screw.

Pushing a Swivel Pin (4)



Next, be sure to have a steel plate underneath the jack screw so you will not damage the cast dovetail that locates the nut.  The tapered pin hole in the swivel jaw and the static support has a through hole so you can get to it underneath inside the square slide area.

The 7 inch Prentiss I show in my top picture will most likely have to be drilled out and removed with a slide hammer.  I just know it.  I’ll add a picture when I get to this repair. I will be using plenty of heat from my oxygen and acetylene torch.  When using heat, be sure to heat around the pin.  I like having the flame pointing away from the stuck pin, and on the mass around the pin.  If you heat the actual pin, it will expand the same as the casting.   You want the steel around the pin to expand and break the rust seal holding the pin.  keep pressure underneath with the jack screw and eventally she will pop.  You don’t have much time heating though, because the pin will inevitably warm up too. Doing this a couple of times will work.


The Prentiss pins are made to 3 degrees per side, 6 degrees for the included angle.Prentiss # 20 pin You might need to measure a old pin or vise to figure what angle the pin is that they used.  Some have suggested cutting a thin shim and hand file the angle till there is no gap.  Then use it to set the angle on your lathe or angle grinder.  I prefer to measure the major diameter then the minor diameter subtract the two and divide the sum for the triangle end. Then measure the length of jaw support for the other leg of the triangle.  Use simple trig (TOA) Tangent = opposite over adjacent then atan the sum for your angle.  Some just duplicate the geometry on a CAD system to figure the angle like what I do. Prentiss-swivel-jaw

This drawing is a cut away view of a Prentiss 19-1/2 Swivel jaw. I added the triangle for this example.


Making the pins can be done in a couple ways.  I like spinning the pin in a surface grinder on a sine plate with a spin fixture. The ground surface is a clean way to make angle pins. If you have a lathe, then it is an easy angle adjustment on your compound.  You can be creative on the knob end.  Make it a full ball, or what ever shape you want.  I like adding a 3/16 hole through the side in case it ever gets stuck. Prentiss #20 pin

I also like to build the pin out of 303 SS so it will not rust. Stainless Steel is a soft metal but will hold up fine under clamp pressure.




Those Pesky Wilton End Cap Pins

I see older Wilton vises fairly often where it looks like the end cap pins kept working themselves out.  On some the owner welded them to the static jaw support.  I have a simpler and more effective way to take care of the problem so that the vise can still be taken apart and reassembled easily.


Welded up end cap pin.

Eventually, the two 1/4″ pins that hold the end cap support and nut will either need to be replaced or taken apart to clean the nut. Wilton uses a straight soft pin that is drilled and reamed through the static jaw support, the end cap support, and finally the cast nut. This pin aligns two separate parts on the tail end of the vise. Two pins are used and must be removed by driving the pins out from one side.  I have had a few that were tight and I had to remove them by welding a slide hammer to the pin and pulling them out like the welded ones.


Setting up the puller for welding.


I like using a TIG welder.

This 5 inch vise takes a 1/4″ pin diameter drilled and reamed in line connecting the end cap housing and nut.  I decided to assemble it a little more simply to make it easy to take apart.

Pin Replace I started by clamping the static support to an angle plate.   The pins are perpendicular to the base and in line with the jaws.


I added a gauge pin so I could sweep in the pin with a indicator to pick up center  Then I ran a tap through the static support. Take a thickness dimension of the static wall thickness so you know how deep to tap . You can also do this with a heavy duty drill press.  It just takes longer to set up.


Tapping for a 5/16:18 thread size.

I like to hold the nut in by jamming a piece of wood in the end.  The two pin sizes I have seen are 1/4″ for the larger vises and 3/16″ for the smaller vises. These two size pins are perfect for a 5/16:18 (tap drill .257) and a 1/4:20 (tap drill .201) thread size.


5/16:18 x 1-1/2 Socket Head Cap Screws.

I purchased some long set screws from McMaster Carr and chucked them up in a lathe and turned the ends down to 1/4  (.250) of an inch to slip into the reamed portion of the assembly, tap drill size for a 5/16:18 thread is .257. Another way to turn the 5/16 set screw down to a 1/4 inch is clamp the set screw in your drill press and use a disc grinder and slowly grind down the threads to a 1/4″.  Take your time and check often with a set of calipers or a micrometer.  That is how I made the ones in the picture.


Ready for assembly and painting.

Pretty simple fix and real easy to disassemble.





Removing Stuck Jaws From a Bench Vise

Like everyone else, I get a few vises with the screws either smashed or the wrong screw hammered into the jaw screw pockets. Here is a quick way to remove screws if you have a TIG welder. Removing jaws with TIG (1)Coming up with a way to hold the screw so you can use two hands for welding is the trick.  If you can get comfortable, then you have a better chance of welding the screw head and not the jaw.  I like to use magnets to align the bolt.  It is hard to tell by my picture, but I like using these small 1/4 diameter super magnets.

Removing Screws (3)Some jaws are a little harder to remove.  This small #825 Wilton (2-1/2 jaw width) gave me fits.  The jaws have been on the vise for many years and were ground smooth to the casting. The 10:32 screws were tough to weld around, but I got lucky.  Removing Screws (6)I used a magnifier inmy hood and saw the tack welding of a #6 screw to the head of a #10 screw.





Once I removed the screw, then I had to weld a slide hammer to the jaw and pull it from the Static and Dynamic jaw support.

Removing Screws (17)

The alignment dowel pin is suppose to be a press fit to the jaw, but over the years the dowel sometimes rusts into the jaw support casting.  I welded right to the jaw with my slide hammer, then after the weld cooled, I hammered it off.

Removing Screws (19)    Having access to a welder, the TIG has more control and a more accurate method of adding filler rod, but a good wire welder can  have success too.  Good luck.

# 3 Chas Parker Jaws Fit and Finish

Once I see by the customers  pictures and sketches and feel pretty good about building their jaws.  I need to correct the miss alignment in the jaw faces by adjusting the angle on the sine vise and re dressing the angle on the wheel to finish grind the jaws. One angle must be dressed on the bottom of the grinding wheel and the angle on the back side is set by the sine vise. I relieve the wheel for side wheel grinding to finish both angles.

Wheel ready to finish sizing the jaws.

Wheel ready to finish sizing the jaws.

Using a ball endmill and stepping over to cut the top radius.

Using a ball end mill and stepping over to cut the top radius.

Next is cutting the top radius. I create a surface model of the top arc in my software so my Cutting software will follow the surface. It cuts the arc by stepping over .05 and down .025 for roughing and a step over of .007 for the finish cut. The small step over along with a large ball end mill like a 3/8 diameter gives you a small peak to peak point that is easy to smooth down.

Finish cut of .007 step over leaves small peaks to smooth out.

Finish cut of .007 step over leaves small peaks to smooth out.




Next is adding the pin holes, if possible do it on a milling machine, even using a good drill press if the vise is a small one. Or using a hand drill also works. I drill and ream the hole for my customers and this allows the customer to use the same drill size to spot the center of the hole, then drill 1/64 under the finished hole size before using a reamer to finish the hole.


Picking up the C/L of the jaws before reaming the pin holes on a sine plate.

Picking up the C/L of the jaws before reaming the pin holes on a sine plate.

I have a Bridgeport 12 inch sine plate that I used for my #956 (6″ jaws) vise. The angle came out to 6 degrees so I could drive the 5/16  pins out from the bottom. It takes longer to get set up then it is to drill and ream the holes. I also include soft pins that are knurled at one end to provide a good press fit and making sure the pins do not work loose.

I use a Scotch Brite pad for finishing.

I use a Scotch Brite pad for finishing.



Now you are ready for cleaning up the radius cut and smoothing out the rest of the jaws, I mark the jaws underneath for assembling  after heat treating. Now the jaws are ready for Heat Treating.

After heat treating and with knurled pins.

After heat treating and with knurled pins.

They come back at 54 to 56 Rockwell hard. A lot harder then the original jaws from Chas Parker. A hand file cuts the original jaws and just slides over the new set.  Back from heat treating your choice is to mount them to your finished restored vise or do more hand polishing to remove the colorful design you get from heat treating. Final assembly by driving the knurled pins in.

8" jaw width.

8″ jaw width.

A very nice finished Chas Parker # 978 vise.

A very nice finished Chas Parker # 978 vise.

Here is a finished # 978 Parker from Chuck in Tucson. These jaws are 8″ wide. Really nice job of restoring this old Chas Parker vise. Yes these jaws are expensive to build, but having one of these old Parker vises with ruined jaws makes the vise below par. The old USA iron should if possible be brought back to working condition. If you are interested in having a set of Chas Parker jaws built then please visit my site Here.

# 2 Chas Parker 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)

# 1 Building the Chas Parker Jaws

978 Chas Parker 8″ jaws

I’ve been building jaws for some time now, and have been asked to build a couple pairs of Chas Parker jaws by various people.  Well, it took me a year before I decided to try my luck.  I was sent two different 8″ jaws from two different 978 Parker vises.  I own the Parker 956 (6″ jaws) vise, and my neighbor has a  973 (3″ jaws) in excellent shape.  Then another customer sent me a 4-3/4 set  to reproduce.

So, I had three to fit, and one extra size to build.  Hopefully I could do this.  Being a retired Mold Maker, I knew they were not impossible to make, but  selling them would probably be the hard part because they wouldn’t be cheap. Building these particular jaws would be very time consuming and require many setups. I don’t own a Wire EDM, a Horizontal Milling machine (which was used to build them) or a 4th axis VMC machine. I do have  a knee CNC and a surface grinder. My 3-d software that I used  building Injection Molds would also be a big help.

Chas Parker-956 (2)

Chas Parker 956 6″ jaws.

8 inch parkers (2)

Measuring 8″ Parker jaws on a CNC with a microscope.

8 inch Chas Parkers (7)

8″ Chas Parker’s serration cutting.

First I had to figure out the geometry.  I used a microscope in my CNC and found points that I could create in my CAD program like a dot-to-dot puzzle.  The A-2 tool steel I use was expensive, so I really didn’t want to make any mistakes. After I created the geometry, I double checked the angle on the surface plate just to be sure. The top and face angle on the vise must be nails on or the jaw faces will not meet flush when you close the vise. I was trying to figure out why Chas Parker used this design, and the only answer I came up with had to do with the jaw support. If a hammer blow was missed, the Static and Dynamic jaw supports would not break like you sometimes see on simpler jaw designs found in Wilton’s.

My evaluation was that all four jaws were built with different angle. This creates more work, so instead of creating this angle on a Staggered Tooth type cutter, I would have to create the angle on my surface grinder wheel instead. I didn’t want to make different angled cutters and have to re-sharpen them to the right angle.  It was easier to dress the correct angle on the grinding wheel, but first the jaws had to be roughed out before going to the surface grinder.

Chas Parker first cuts (6)

Sweeping in a gage pin to find the edge of the Parker jaws on the sine plate.

After I cut the serrations, I set the blocks up in a vise bolted to a large sine plate made for heavy cutting on a CNC or a Bridgeport type machine.  The jaw block had to be located precisely on the correct angle; the 8″ was set at 12.54 degrees and the others were up to 18 degrees like the 3″ set.  I used the CAD program to calculate location but it could also be done with trig. I also set the tools to the top of the pin because I found this was the easiest for setting all my cutters.

Chas Parker first cuts (8)

Scallop cutting with a 3/8 ball end mill.

After roughing out most of the material,  I programed cutting a finishing cut with a ball end mill.  I did a step over with 3 dimensional cutting of .015 per scallop.  It took time to cut that way, but it was the simplest way I could do it with the machines I have.

I’m excited to write  about finishing and fitting the incredible Chas Parker jaws, but I have to end this blog until I can get caught up on my Wilton orders.  So stay tuned.  You’ll be able to find them on my other site  benchvisejaws.com as soon as they’re ready.