What is your set up for grinding integrals?

[gudspelr]

I’ve been thinking about integrals and finishing a grinding fixture that I started a while back. It got me wondering about what all everyone has come up with for the task? I’ve seen tricks and tips for forging integrals and keeping things centered as you go. But what do you like to use after the forging is done? Small wheel attachment that is at the end of a long steel platen so you can grind the whole side of the blade? Do you use a regular platen and go at the curves on the front of the integral bolsters with files? How do you like to scribe/find your center line? Last, what do you find as the most difficult part of grinding integrals? Curious for any of your thoughts on the subject.


Jeremy

 

[Toni Oostendorp]

He Jeremy,

Wenn I make my integrals, I forge the blank and leave the guard area thick. I then grind one side flat. This flat side will be my reference point from which I scribe all my lines. It is important to have one reference point, otherwise you have to eyeball every angle and dimension on your knife.

I grind my transition from blade to guard on a flat platten from Nathan the machinist. I position the platten horizontaly and use the rounded corner of the platten.

 

[Toni Oostendorp]

Here is the setup I use

 

[jdm61]

Toni, how much horsepower does it take so that bit won't stall? How loose do you have to leave it?

 

[navman]

Toni...those are amazing!

 

[gudspelr]

Thanks for posting the pictures, Toni. Really nice knives by the way... One set up I’ve seen is similar to yours, just with a small contact wheel at the bottom. It has a steel platen at an angle like yours, but instead if the small radius, there’s a contact wheel that helps grind in the larger radius often seen on the guardless type of integrals. I’m curious as well to hear how tight you keep the tension for the belt as well as the speed.

Jeremy

 

[kuraki]

My issue with setting up like that has always been friction causing the belt to slow, drive wheel to spin and then throw my belt. I worked really, really well, but if I made a tiny misjudgement in pressure, zip the belt flies off.

I was holding off until I got a rubber drive wheel or something. But maybe it was heat buildup as well, since I didn't have as much mass or a chiller.

I've though about trying to build one like you're describing G gudspelr with wheels, and just haven't had time. I think it can be done. The trick being minimizing the amount of belt that bridges a gap between the platen and wheel.

 

[gudspelr]

Kuraki-that’s definitely one of the challenges. Bringing the edge of the platen REALLY close to the edge of the wheel. If there’s any meaningful gap between, it's going to complicate things.

Jeremy

 

[Toni Oostendorp]

I have a 2 hp motor and the trick is to give the belt just enough tension. The grinder in the picture has a tension arm without a spring, so I tighten it by hand. Your grinder has to be aligned really well, otherwise the belt will jump.

 

[kuraki]

Here's kinda what I was thinking. These are .75" rollers. That's about as narrow of a belt gap for that roller size as I can see being practical. When I make this I will probably leave the platen a little proud, assemble and dowel the rollers in place, and then surface grind the platen until I tickle the rollers. I don't know if it would work to make different bearing holders (green parts) for smaller rollers or not, but I would probably try. Or, maybe I would make one side a .25" roller and the other a .75" or whatever sizes and flip flop rather than swapping parts.

 

[gudspelr]

Kuraki-
This link is to Steve Culver’s site/pictures of one I was trying to model mine after. It solves the problem of needing a wheel on the other end (coming from the idler wheel side). Although you’re looks pretty darned nice in that drawing. And having the different diameter wheels would definitely be nice.

https://www.culverart.com/Jigs and Fixtures.htm

Jeremy

 

[kuraki]

Oh that definitely looks like it would work well.