Rotary Platen Plans?

S

StuNY

Joined
Feb 16, 2014
Messages
152
I am going to tackle making a rotary platen for my grinder to help with making convex grinds on my Japanese kitchen knives. Most of it looks pretty straightforward- I made all the wheels for my grinder- but I am not sure about the spacing between wheels? I have the specs for the 26" belt so can figure out an arrangement that works, but wonder if there is a method to how the commercial units are spaced or is it not that critical? Also, I can't see from pictures how they are adjusting tension on the belt unless it is just loosening the back support wheel and pushing into position/tightening? Seems I am missing something and there should be a knob to dial in proper tension?
Appreciate any help!
 
Here's mine. It's based off using 2" OD wheels and a 26" belt. However, I would use 2.25" wheels or I would slightly extend one of the legs a little bit, since I'm maxed out in my slot length to get the tension I want. I didn't make a complicated tension device. It's simply a "t" nut that is captured in the slot and locked down with 2 cap screws. I don't ever change the tension so I didn't see the need for anything else. I put the belt on, snug the screws up, then tap it back with a hammer until it's where I want and then torque the screws down.

0mwcY69.jpg
 
Mine is like link #2 and #3 and the diagram of Kuraki. The wheels are of varying spacing, to give different degrees of slack. I would say the open spaces between them are 2-3-4-5" spaced. I keep the tension pretty high.
 
Thanks for the photos and advice guys! And the drawing Kuraki. Looks like I have what I need to get started! Seems that 3/8" steel or 1/2" aluminum should work for the plate.
 
Kuraki, Going off of your drawing, is it possible for you to add locating dimensions for the slot? Going from left to right or right to left there is no reference point to go off of, same for height. Only what looks to be the length end to end of you were to drill a .625" hole ate each end to get the ends of the slot.
 
StuNY said:
Thanks for the photos and advice guys! And the drawing Kuraki. Looks like I have what I need to get started! Seems that 3/8" steel or 1/2" aluminum should work for the plate.
Click to expand...

I used 3/8" 6061 aluminum.
 
I just bought a rotary platen. The wheels on mine are serrate (grooves around circumference) and the rubber belt is grooved to match, to stop the belt slipping sideways when grinding more on one side. I would imagine making such wheels by hand would be a pain.
 
I found the wheels with grooves. I just need the file for the bracket. Someone had a link to it above but the link is now bad. If I can’t get the file I’ll just recreate it with the plans on this thread.

thanks!
 
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