grinding tips

[NittanyRider]

I've managed to hammer out a few knife-shaped objects, so it's time to get acquainted with the belt grinder... curious if any of you have a useful tip or two, for doing flat grinds, that you'd be willing to pass along?  

Thanks, David

[tomsm44]

With anything related to knife making, faster is rarely better.  Go SLOW.  If you can adjust the speed on your grinder, start with it on the slowest setting.  I use a stepped pulley system on mine and almost never take it off the slowest speed.  Use good belts.  They're cheaper in the long run because they last longer.  Most makers grind with the edge up.  It'll remove the most metal where you put the most pressure.  Start at the edge and get it fairly close to the final thickness, then apply more pressure toward the spine to move the grind line up toward the spine.  And go SLOW.

[gudspelr]

Soooo, I'm the world's slowest knife maker... I started a WIP last year, and life and family got in the way, and the knives aren't finished quite yet... But-in the below link, I have several pics along with some explanations of how I flat grind. Matt gave some great advice already and I pretty well do like he mentions. Hope something in here helps.

 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=110;t=005181#000000


Jeremy

[kbaknife]

The single biggest help in all types of grinding FOR ME is having a variable speed grinder. (Two, actually.)
When you have a single speed grinder - which I don't even think should be built - and it's flying around at full speed, even small deviations cause big accidents fast. Really fast.
Outside of practice, practice, practice, I would say:
Variable speed, ceramic platen and high quality belts and decent tracking.
Technique and procedure/regimen is one thing, but without a decent grinder and grinding components would be like trying to win a drag race without a decent dragster. It wouldn't matter how good of a driver you were.

[Lin Rhea]

Karl's analogy is a good one. Buy more power in your grinder than you are likely to need but you will eventually grow into it.

Again, like driving, too fast is dangerous, but I think too slow is also a bit dangerous and not productive. Work slow but not inhibitive. The driving illustration is great.

I like to be throwing a few sparks so I can see where the metal is coming from and tell if I am flat on the platen or otherwise.

[NittanyRider]

Thank you for the input, guys, I appreciate it!  

Matt - that technique is exactly what Timothy Potier discussed at a grinding demo he did at the mid-america hammer in.  Somehow I had forgotten about it until you mentioned it, so thanks!

As for my grinder... I have a 3-speed KMG, so it's not infinitely adjustable, but I can set it to either 800, 1800 or 3600 FPM.  I will upgrade to a variable speed controller in the future, but since I also needed an anvil, forge, etc, I had to make a concession there.    

I bought some DEER Bora 7 ceramic belts in 36 and 60 grits, plus some other finer grit Norton belts. Any other recommendations?

I'll take some before and after pics once I get a free moment to do some grinding!

David

[NittanyRider]

p.s. Jeremy - thanks for the link.  I will check that out later on!

[tomsm44]

Sounds like you have a really good setup for starting out.  Another thing to consider when talking about speed is the size of the piece you're working on.  As Lin said, too slow can create its own set of problems.  That would be multiplied on a 1/4"+ thick Bowie with a 14" blade.  The same reduction in speed may add many hours to a large knife, but only one hour to a small Hunter.  You can hog a lot of metal off of a large blade early on and then slow down as you get near completion and straighten out any screw ups you made early on, where one slip up early on with a 1/8" thick, 4" blade Hunter can ruin the whole thing.  I mainly build the latter.  I've only built 2 bowies and am partially through with my third, and those are the only three times when I have really sped my grinder up.  Also, your goals need to be considered.  If you are trying to sell a knife, going too slow would either make you have to raise your price or make less $/hour.  If it's a hobby, like for myself, and you are mainly making small knives to give to friends and family, the extra time used is less of an issue.

[NittanyRider]

Those are good points to consider, Matt.  Thank you, again.

Like you, my main goal is to make hunting knives, but I'd also like to make kitchen knives for myself and my family and friends. Since I don't have a "time is money constraint", I plan to learn this craft slowly and to the best of my abilities.      

I'm also going to have a LOT of questions for you all... just warning you now!