Problem

Walt2

Walt2

Joined
Mar 13, 2001
Messages
1,157
I recently bought a Coote grinder and have just ground my first two blades with it and it worked great. I did come up with a problem that I've never had before, don't know what caused it. On the same side of each blade there is a horizontal small dished, or depressed line, about 11/4-11/2" long, about in the middle(top to bottom) of the blades, starting close to the plunge cut. It only did it on one side. This appeared after I switched to 220 grit. The 220 grit belts are Klingspor. I also noticed that on one of the blades, on the same side as the horizontal dished line, there is a couple of small slightly dished spots about 3/16" in diameter. Do any of you guys have any idea what could have caused these dished areas. I have never experienced this before. Thanks

Oh, by the way, the steel is CPM3V.
 
can you post a picture? Are the lines following the edge(horizontal?) you may have a burr or a ding on your platen....but thats a guess....
 
I use the Klingspor yellow belts from 120 to 400 grit and have no problem :confused: , I'll bet it's the platen.

Don Hanson lll
 
What is puzzling, is that it only did this after I switched to the 220 grit and it only did it on one side of each blade. It is on the same side of each blade. It would seem that if it is the platen, that it would do it on both sides of the blade. Looking down on the spline, it is on the right side on both blades, nothing on the left. The dished line does not follow the edge, it is about in the middle(top to bottom) of the blade. As I said, I have never had this problem before. I have been using 2X48" Klingspor belts on my other grinder and never saw this. I'm wondering if the belt starting to get a little dull had anything to do with it? This steel seems to dull belts rather quickly. I have hand sanded most of one of the lines out of the samller blade and am finding out about hand sanding 3V!!!! I do not have picture posting rights.
 
Get a piece of pyroceram the size of your platen and glue it on. That should cure the problem.Make sure it pushes the belt out a bit.

Someone here should have contact info to get pyroceram.
 
I have a Coote too and what Mike suggested is what I was thinking. Do a search on Steve Pryor. He'll fix you up with the pyroceram. I also use Kingspor (CS310 series).

RL
 
I agree with D. Sylvester. You may be holding the knife up a little higher (or lower) on the right side and catching the end of the platten. When I switch to the finer grits I am putting less preassure and sometimes I'll move the blade a little higher on the platten to see better.
 
***Warning potentially stupid question***

How thick are the pyroceramic platen liners? I too have a Coote and have heard the liners are almost a requirement, however I work with the platen rest (sorry) and I don't know if the liner would fit and still leave me room for a belt!

I'm afraid the answer is take off the work rest and learn how to grind properly, but that's too hard. :D :rolleyes:


Thanks

Jared
 
Jared P said:
***Warning potentially stupid question***

How thick are the pyroceramic platen liners? I too have a Coote and have heard the liners are almost a requirement, however I work with the platen rest (sorry) and I don't know if the liner would fit and still leave me room for a belt!

..................Jared
Click to expand...
Somewhere between 1/4-3/8" in thickness. Dont they have an adjustment to move the workrest further out?

If not, maybe fabricate a better system, or call Rob Frink and have him do it.

Or, take off the workrest, and learn how to grind properly!;) :D

Edited to add; here's a link to Robs place.
http://www.beaumontmetalworks.com/
 
Walt, you may have to break the platen in. I know that sounds stupid but, I just got my new KMG running and had the same thing on my very first blade, a large 10" bladed camp knife. The second knife I had no problems. I know that sometimes I get crap caught behind the belt, on the platen. That's why I spray the platen with WD-40 every once in awhile. I'm getting some pryrocerum when Rene gets back but, even so I've ground blades on steel platens for the last 4 or so years. By the way, I use Klingspors for 220, 400 & 600 grit and have for a long time.
 
Thanks for the suggestions. I know that I am not holding the blade too high on the platen. I use the work rest and the platen on a Coote goes rather high above the rest. I don't have much time to play with the grinder right now. I have a project that I am working on right now on the house. We had a couple of days of weather that shut me down, so I ground a couple of blades. I have upgraded my membership, and one of these days maybe I can figure out how to post pictures.
 
Well, I had to go out of town unexpectedly for a few days and didn't have a chance to look at the grinder until this afternoon. I found out what was causing the the dished places in the blades, but now I'm puzzled where it is coming from. There was some areas on the platen that had a brown buildup stuck to the metal. There also was some on the top metal roller. There actually was quite a bit of it on the roller. WD 40/acetone either one would not touch this stuff. It was like it was baked on. I used a stainless steel brush that is normally used to clean welds to brush it off, and it still wasn't easy to get off. Since I have used Klingspor belts on the other grinder without this sort of thing showing up, I am wondering about the 3M 967F Cubitron belts, if this is where this gook came from.
 
It is either the glue from the butt splice rubbing off on the rollers and platten,or grinding grit getting sprayed up onto the back of the belt and getting burnished (accent on the BURN) onto those metal parts.I have had to sand this buildup off at times.It gets rock hard - doesn't it?I have been told that incorrect belt tension can cause this,too.
 
well have you tried giving it to Steve for free???
all your problems gone in a single shipping package!!! hahahaha
:D :D :D

maybe the brown build up is from ppl like me drooling on it when you're not around! lol
good luck ;)

Steve.
 
It is the 3M belts. After a few minutes use, the brown stuff will start getting on a pulley/roller and then will start getting on the platen. I like the way these 967 Cubitron belts cut but if the rest of the ones I have are like the two I have used, I won't be using any more. I would be spending as much time cleaning this stuff off as I would grinding.
 
Walt2 said:
It is the 3M belts. After a few minutes use, the brown stuff will start getting on a pulley/roller and then will start getting on the platen. I like the way these 967 Cubitron belts cut but if the rest of the ones I have are like the two I have used, I won't be using any more. I would be spending
as much time cleaning this stuff off as I would grinding.
Click to expand...

I've never heard of that with 3M belts. Try the 977's. I use them and have never had any problems like that. Call the place you bought them and tell them about this problem. Or better yet, call 3M abrasives and tell them. They'd be very interested in that peculiarity.

One last thing, you might try spraying WD40 on the inside of those belts, and see if that doesn't help.

http://products3.3m.com/catalog/us/en001/manufacturing_industry/abrasives/node_V1MTKD8BBLge/root_GST1T4S9TCgv/vroot_1NJV8BGHDNge/theme_us_superabrasivesolutions_3_0/command_AbcPageHandler/output_html

http://www.3m.com/index.jhtml
 
You must log in or register to reply here.
Back
Top