Bad Shoulder

[Howard Rich]

I am working on my first damascus blade. It's a 5"x 1 1/2" blade, carved Afican Horn folder done in the primitive over the back spring. I stopped working on it becaues my first time flat grind has a shoulder that is anything but straight. Now, my belt grinder is a 2"x36"multi-tool the flat plate has rounded edges and I can't tell if it's me or the rounded edges on my flat plate that won't let me keep a straight line.
Any suggestions?
Howard

[Ray Rogers]

Hard to be sure that I'm answering the question you're asking but I see several possibilities.

I don't know your skill level or what other blades you may have made. If you have lots of grinding experience then I would expect that you have ground straight shoulders before. If that's true, what's different this time?

If you don't have much grinding experience, then put that damascus away - it's too expensive to practice on. Make that same blade out of cheap carbon steel and keep making them until you can grind straight shoulders. As you gain experience you'll figure out if the problem is in that grinder or in your control.

Those round edges may not be helping but they shouldn't absolutely prevent grinding a straight shoulder. They would force you to have rounded plunge lines but they should still be straight.

If you think the round edges are the problem, then make another platen for your grinder (assuming you can't talk your wife into getting you a better grinder for Christmas)....

[george tichbour]

Buy a 2nd cut file and a smooth cut file and draw file the blade to straighten up the grind line. Eventually you will not need the files but at least in the mean time you will be able to make something.

[Howard Rich]

This is my sixth knife but it is the largest and the first flat grind edge all the others I did a hollow grind on a double wheel grinder that I made they came out great I sold at cost them already.
A point of interest, I traded jewlery I made for the damascus so it so it cost me less than anything else.
I will try to load the photo.
Thanks

[bgmills]

Howard, I don't have an answer for your question, but could you post a picture of your "double wheel grinder"? Thanks for your time!

Bill

[Howard Rich]

I can't post pic of the grinder becaues of the way the forum wants it done. I tried all the ways the experts wanted several times to no end and still no photos.

[SteveS]

You can try making a bumper - it helps.

The machinists amoungst us might suggest a more precision tool, but this works for plunge cuts.

Get 2 pieces of scrap steel at least 1/8" thick - 1/4" better yet. 3/4" wide or so and 2 or 3" long. Get 2 1/4" bolts with nuts.

Stack the steel neatly and drill 1/4" 2 holes thru both pieces. One each near the ends. Now bolt them together and go to the grinder. Make one edge nice and straight and flat.

Loosen the bolts and stick the blade between them. Line up the smooth edge of your bumpers just behind where you want the plunge cut and re-clamp with the bolts.

Now back to the grinder. NEVER EVER move the blade up to the belt right at the plunge cut. Ease it up there at least a 1/4" away. After you have contact, then move the blade so the belt is in the plunge.

The new bumpers you just made will keep you from going to far and will keep your blade angle constant.

Have fun. On future knives try your bumpers at different angles. You can make all sorts of effects.

BTW with rounded edges on your platen, you'll probably always have rounded plunge cuts. There's nothing at all wrong with that if they are straight and both sides are the same. Bumpers will make sure of it.

Hope that helps,

Steve

[Howard Rich]

Thanks Steve!
I will try that, I also put on a Corian flat plate and that gave me a nice right angle at the belt edges and it worked. But I will try the guide idea too.
Thanks
Howard