Disk Grinder

JTknives

JTknives

Joined
Jun 11, 2006
Messages
8,651
I have been heavily considering adding another disk grinder to my shop. Right now my disk grinder is one I made, 9" with a 1.5hp baldor motor. It's not reversible or VS. It works great what I use it for which is scales and other things needing flatness. I'm doing more and more hand sanding of blades and need a way to speed up this process. I'm considering using a disk grinder with rhynowet paper and going up to a fine grit and then switching to hand sanding. I will grind the flats on my 2x72 and then switch to the disk. I have been thinking about putting a plug on my belt grinder VFD so I can run a 3ph disk grinder motor.

With all this being said what disk setups are you guys using for this. And also are you using the beveled disk or the flat disk. I can see advantages of both but being that this is going to be used for blade flats 99% of the time so looking for advise. Thanks guys.
 
My 2 cents again. Use a flat disc and a KBAC drive with a reverse switch. A 1 hp will do anything you want...it's not like a grinder where more hp is always good. You will be using wet paper at slow speeds and even then your paper will only last a minute. Use it like it's free as many say. Go slow and change paper every minute to get a nice flat finish before hand sanding. You will barely have to hand sand after the disc. My opinion. Larry

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That what I'm hoping. I have been working on some D2 bird and trout knives and man the hand sanding on one blade to 600 grit took my all day. Wife walks in and says "your taking a long time on a knife your going to sell for $150", I love her to death for just this ression, I get lost and caught up in somthing and don't keep track of time. That got me really evaluating my process and looking for a way to decrease time and increase quality. Work smarter not harder, I have a bad habit of stretching out my sand paper WAY past the useful point. I am trying to break that habit and toss it once I feel it stop cutting. Like I said I love my disk but there is no reverse and no speed control so it's running at 1725rpm.
 
Jt, If you can part with the bucks for a VFD with reverse you will have so much control over your flats and will also be able to square up anything from bolsters to scales. I buy paper now a hundred sheets at a time and it costs plenty but the price per sheet goes way down. I plan to do this for a long time so having a huge stack of Rhynowet and Black Diamond papers is cost effective. You will have more fun making those $150 knives when you make them easily. Just use half a dozen sheets of paper at 50 cents a sheet and charge $155 for those knives. I get my profiled blanks flat and semi polished with the disc even before I grind the hollows and when they come back from heat treat they are so smooth that I can just hand sand the flats with a piece of flat steel and touch up my hollows and take the edge down in minutes. Just my opinion. Larry
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This batch of blade where ground to a A65 (240grit) finish with a gator belt then I switched to 220grit paper and it just takes for EVER. It seams like there is always a hand full of deep scratches that are a bear to remove. I don't mind using the paper at that price. That math is easy, all day vs a few bucks for paper.
 
I'm using a beveled beaumont disc and a teco vfd. The beveled disc leaves a small hollow. I wish I would have just bought a flat disc. It's not too bad to hand sand the hollow out, but I think a flat disc would have been better for me.
 
That's what I was wondering, as I thought about it more I wondered how hard it would be to remove that very slight hollow. I have a nice VFD that I'm going to share with my belt grinder. So look like I just need to round up a 3ph motor, a 3ph AB switch and a nice disk. I like my disk but it's not perfect and I would rather leave it as it is. It's horizontal and works great for scales. Are you guys using type of rest on your disk grinder for doing edge bevels? I grind free hand on the belt grinder so I was thinking I did not need a rest on the disk.
 
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