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Radius platens, platen chillers for KMG

Nathan the Machinist

Nathan the Machinist

KnifeMaker / Machinist / Evil Genius
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The radius platens are made of A2 and hardened to HRC63-64. There are two sizes in this sale that simulate large wheels, 36", and 48". They're $110 each. There are 10 of each.

If you buy a radius platen you're probably going to want a water cooled platen chiller because they get hot. They're $60.

Flat rate shipping in the USA is $5.


These are made to fit the KMG standard, which is 2X8 with 1/4-20 mounting holes that are 6 3/4" center to center. Some people have adapted these to other grinders.


If these platens will fit your grinder and you would like to buy one of these, I need you to please follow these instructions to help me keep up with everything (otherwise folks will fall through the cracks).

1: State your claim in this thread.

2: send me an email (not a private message) carothersknives at gmail dought com

The email should include what you are buying, your BladeForums handle (i.e.: "Nathan the Machinist"), your actual name, your shipping address and your paypal email address.

I will send a PayPal invoice to that email.

3. Pay the paypal invoice. Once it is paid, I will ship your order to the name and address you gave in your order email.

If you don't want to use paypal, we can arrange to send a check.

If there are shortages it will be based upon first come first serve who posts in this thread. I have to do it this way to keep things sane.
 
Radius platens simulate large wheels. They're called a "radius platen" because they're machined with a radius. The size number references the size wheel they simulate. So a 36" radius platen actualy has an 18" radius. It simulates a 36" diameter wheel.

radius_platen.jpg~original


There are ten 36" platens, ten 48" and one 72".

Personally I like the 36" the best. 48" is the most popular. 72" is too subtle to really notice with your eyes and is mostly used by folks making certain kinds of kitchen knives.

In using the radius platens I have found the effect is subtle, but noticeable. It isn't a flat grind, but it isn't really a hollow grind. I believe this is a historically accurate grind for blades ground in yesteryear on really big stones. I see this being a cool grind for blades made in an older style, and blades like kitchen knives where you would want a full height grind on a tall thin blade.

36_hollow.jpg~original



The A2 is quality steel from Latrobe, heat treated at Peter's Heat Treat with cryo and is harder than a woodpecker's lips. But it can still wear out quickly if exposed to certain grinding conditions that cause grinding grit to accumulate on the inside of your belt and cut the platen. Some belts have dry lubricants, coolant and other "aids" that work great on a contact wheel but can cause black gunk buildup on the inside of the belt that can then cut the platen, particularly when they get hot or damp. If you're getting black buildup on your platen beware of cutting grooves.

Unlike a flat platen that you can re flatten, a worn out radius platen is toast. You can extend the life of your platen by not using it to rough or profile. If you establish your grind on a regular flat platen or wheel and if you'll avoid cutting it with grinding grit your radius platen will develop a mirror finish and can grind hundreds of knives over its life before developing troublesome wear.

You will probably want a platen chiller if you're using a radius platen.



The water cooled platen chiller is a very useful gizmo. You just about need one if you're grinding with a belt warped around a formed platen, but even folks doing regular flat grinding have found these to be very useful. I've gotten a lot of great feedback about these and I use mine all the time and wouldn't want to be without it. Grinding against a cool platen is a good thing.

chill1.jpg


These have an internal meandering water path circuit where you can pump, siphon or otherwise flow water to control the temperature of your platen. I use ice water and get mine cold.

chill2.jpg


The mating surface is precision machined flat and the back of my steel platens are also precision machined flat so you can simply bolt these up and get fairly decent heat transfer. For better heat transfer or to use a platen I didn't manufacture you can use a little thermal grease during assembly to get really good heat transfer.

chill4.jpg


The chiller is sealed with a buna N o-ring that is rated to 250 F. The o-ring is compatible with water, antifreeze and most oils. It is not particularly compatible with acetone, so if you're planning to flow subzero acetone through it for use as frozen quench plates - you probably shouldn't. The assembly can be opened to remove clogs or replace the o-ring if necessary. If opened, you should use a little smear of grease to lubricate the o-ring upon reassembly.

The pipe thread is a standard 1/4 NPT. You are responsible for hooking up your own coolant supply. I recommend swivel push-to-connect fittings and 1/4" or 3/8" plastic tubing, though rubber hose and hose barbs work too. I'm using a dinky little centrifugal pump here and a bucket of water. The meandering coolant path in the platen chiller induces a lot of turbulence in the water flow which helps you get good heat extraction without needing a lot of water flow. An aquarium pump is adequate. Or you might opt to hook up to your regular water supply and simply dump the water (though you'll go to hell for wasting water). Just remember you don't need huge flow or pressure here. Keep up with your tubing to keep it out of the grinder wheels and mechanism using zip ties or similar.


Put ice in your bucket for a cold platen. This can reduce your need to lift while grinding, particularly when using formed platens that can get extremely hot.
 
Nathan the Machinist said:
The radius platens are made of A2 and hardened to HRC63-64. There are two sizes in this sale that simulate large wheels, 36", and 48". They're $110 each. There are 10 of each.
If you buy a radius platen you're probably going to want a water cooled platen chiller because they get hot. They're $60.
Flat rate shipping in the USA is $5.
Click to expand...

Hi Nathan,
I'd like to get the 36" radius platen and the chiller.
Email coming shortly.
Thanks!
 
Nathan, are you going to have and of your flat platens available anytime soon or do you happen to have any currently?

Jay
 
Nathan
I emailed you and unsure if you received as I have not received any confirmation from you or a PayPal invoice.
If you send me a email to gonzoweld@yahoo.com maybe that Will work.
Thank you
Bryan
 
B.Gonzo2013 said:
Nathan
I emailed you and unsure if you received as I have not received any confirmation from you or a PayPal invoice.
If you send me a email to maybe that Will work.
Thank you
Bryan
Click to expand...

Sorry Bryan, we didn't get your email


2: send me an email (not a private message) carothersknives at gmail dought com

The email should include what you are buying, your BladeForums handle (i.e.: "Nathan the Machinist"), your actual name, your shipping address and your paypal email address.

Once that comes through someone here will process it

Thanks,
Nathan
 
One other use for these is for grinding perfect curved clip points. the 72 inch works very well on bigger bowies. You just set the curve and then angle the blade over to the side to grind the swedges. ;)
 
Nathan,
I would like one of your 48" platen and chiller, and one of your small radius flat platens.
email on the way.
thanks
 
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