My Bolt-Together Pin Press

[Dave Larsen]

I've been pounding my thumbs too long! A pin press has always seemed a perfect answer to setting bolster pins. Beside hitting myself I often found the bolsters shifted enough to leave a visible line when I tried to pein the pins. This baby resolves all that.

Fellow forumite navajas convinced me I didn't have to weld my pin press together but could simply bolt it all up. That idea let me get this thing built, rather than continuing to wish I had access to a welder. Thanks Roland, I would never have done this without your help.

The anvils are hardened; everything else is mild steel. The whole thing cost less than $50 - the jack is from Harbor Freight and was on sale under $30. I bought a 3/4" drill bit because I was too lazy to file out the big holes for the all thread; otherwise all simple tools.

This is a low tech machine with surprizing accuracy and power. I'm pretty pleased with it so far! If the pics don't answer your questions and you'd like to see something better, just let me know and I'll get better pics for you.

Here are the parts before I put it togther:



And here's the final version:



Hope you like it, this just goes to show you don't have to have any special tools or extra money to get set up to make knives!

Dave

[navajas]

Way to go Dave!!!!
That looks really good. You did a nice job my friend. I,m glad I could help you out. Keep in touch.
Roland

[RickNJ]

That thing looks really cool. I think I might want to build one of those in the future. :cool: If you can put one of these together for $50 or so, it's a great bargain! Any chance of a small tutorial with a bill of materials and some basic instructions?

[Dave Larsen]

Rick I'll work on that; meanwhile keep in mind there's nothing sacred there, it was mostly all stuff I had laying around. Just start keeping your eyes peeled, it took me a couple months to get everything together and when I did it almost assembled itself! One thing, where I used round tubing and stock you could just as easily use square; it'd probably make some things go better, actually.

The height between the C frames is 18", to give a bit of scale.

Roland, thanks. Have you finished any of your awesome folders lately?

Dave

[Bob Warner]

Great job Dave.


Does the Frankeinsteinian fixture just set on the jack or it is attached? I wouls like to see a tutorial, everyone could use it.

[Bob Sigmon]

Dave,

Great Job ! I think that a lot of these will be built in the near future.

Thanks,

Bob Sigmon

[whv]

nice job, dave. being rather dense, i would appreciate some specs and/or a materials list too.
thanx

[Dave Larsen]

Okay folks, here's my shot at explaining what this thing is for and how I put mine together. If you have any questions I'll try my best to clear them up later.

------------------------

The idea behind the Pin Press is to use a smooth and controllable force to peen the pins and swell them inside their holes, rather than the force of repeated hammer blows. This is much better on thumbs, particularly when the pins are close together! And it makes it much easier to hold the materials flush with the knife while force is being applied to the pins. The end result is a nice quiet, painless peening process!

Bill of Materials:

12 Ton Hydraulic Jack (1)
C Channel (2) 4" X 10"
3/4" Black Pipe (2) 16 3/4"
5/8" Allthread (2)
5/8" Nuts for Allthread (4)
5/8" Washers for Allthread (8)
"Frankenstein" Sleeves (2) 1 1/2" and 2 1/4"
Angle Brackets (4) 3/4" X 1/2"
3/4" Square Tube (2) 1 1/2"
5/8" Round Bar (2) 2 1/8"
1/4" 1095 Anvil (2) Hardened
1/4 - 20 Bolts (23)
10 - 36 Bolts (12)

Overall Dimensions 10" X 19"

The Pipe maintains the space between the two Channels; the Allthread goes inside the pipe and holds the frame together. The Hydraulic Jack is bolted to the bottom Channel. Note the piston of the Jack is not centered on the Channel, but is offset a bit; that's because the base of the Jack is centered on the bottom Channel.

The Anvils are hardened and tapered to a 1/4" square at the "working" surface. This is where all the force of the press is directed, and where the pins are compressed. It's important these are aligned perfectly and that the surfaces meet square and flush - otherwise your knife handle may suddenly squirt out one side under intense pressure. You don't want that.

The Square Tube is used to hold the Round Bar. Each Tube has 4 10 - 36 bolts threaded through it as set screws to hold the Bar in place. This allows the Bar to rotate to help align the Anvils. Each Bar has a slot cut in it the thickness of the Anvil with a 10 - 36 bolt threaded into it as set screw to hold the Anvil in place. Take a look at the Anvil contraption sitting on top of the Jack piston in the picture to see this all put together.

The "Frankenstein" Sleeves each have 4 1/4 - 20 bolts threaded into them as set screws to hold the Anvil contraptions in place and to align them perfectly to one another. The bottom Sleeve has 4 1/4 - 20 bolts threaded into it as set screws to press against the Jack's piston, holding that whole Anvil contraption to the Jack as the piston moves up. Note that the Anvil contraption rests on the face of the piston; the Sleeve merely holds it in alignment.

The second Sleeve is bolted to the top Channel in general alignment with the piston; the Sleeve holds the top Anvil contraption against the Channel. Again, the Anvil contraption rests against the Channel and is aligned with the Sleeve.

You can adjust the alignment of the Anvils by moving the piston until the Anvils are close to each other and alternately loosening one and tightening the opposite set screw until everything matches up. Gradually tighten all of them down, keeping the Anvils in alignment. Get everything real tight.

Note that I had to use a shim behind the top Anvil to get it perfectly vertical to match the bottom Anvil. This was because I made the slot in the top Round Bar too large!

The force of the Jack is directed through the piston, the Anvil contraptions, the Anvils to the top Channel. Whatever is between the Anvil faces will get squashed - in this case, pins in knife bolsters or scales.

Caveats: You must ensure the Anvil faces are flat and square to each other. The Anvils must be in perfect alignment to one another. If these conditions are not met you might very well end up with a bunch of knife parts flying at your face under great pressure! Bad!

[Brett Bennett]

Nice work, Dave!

[whv]

thanx, dave, great job. the "anvil contraption" is what i wasn't getting from the pix, even with a 20" monitor.
now, off to harbor freight again this weekend!

[Dave Larsen]

Cool Wayne! If you want bigger pics of something as you get going just let me know. I'll be happy to get whatever level of detail helps. It's nice to be able to give something back after all this time. mailto:dclarsen@mchsi.com

Dave

[Bob Sigmon]

Dave,

Could you get a close up of the anvil with some dimensions as to the height. I'm sure that it's not critical but if it ain't broke.....

Thanks,

Bob Sigmon

[Dave Larsen]

Bob, let's try this. Naturally I didn't measure this thing when I had it out but I'll be happy to get it and do so if the ruler doesn't work. This is an awful muddy photo, just no light. Hope it works well enough.

[Dave Larsen]

I wonder if Crow would taste better in stew? 'Cause I'm about to have a nice fat meal.

It worked fine in my first tests using short half inch pins but this morning I tried it with more normal sized 1" pins. And what happened is the jack-side anvil setup had enough flex that it moved out of alignment and wouldn't drive the pin. Rats. Visions of someone here building this thing filled my head with major embarrassment.

Naturally this has a fairly simple fix, I just tried to avoid it initially. I'll add a lateral support that will move up and down along the pipes and provide something to guide the anvil. Not a big deal really, I just would rather have done it before I posted!

I'll get it done this week and post the update when it's done. Meanwhile, keep this in mind if you start building your own.

Also Bob, the dimensions for the anvil contraption parts are in the materials list, I just didn't think to mention it yesterday.

Okay, off to the yard work...

[navajas]

Dave, Just keep it simple. The less moving parts the better. Use you lathe and make a mandrel out of cold rolled steel with a hardened insert on the the face of the mandril. e-mail if you have any questions. Take care.
Roland