Hollow grinding help needed

I

itrade

Joined
Jul 3, 2002
Messages
645
Hi Guys/Gals,

I have my new grinder running, with a contact wheel and am going to try hollow grinding for the first time. However, it kind of baffles me.

How do you keep contact when you get to the belly?

As you draw the knife across the wheel do you need to tilt the knife as it reaches the belly? Or do you need to pull the tang back to keep the knife in contact with the wheel? Or do you just pull straight across?

My brain is having trouble with the whole distal taper/curved grind line formation.

Of course I'll be chewing up some wood this week-end, but I'd like to start off on the right foot.

Steve
 
Steve, hold the blade, edge up, and horizontal(you can get tricky once used to grinding), put it into the wheel, 1/8" or so short of where you want your plunge to be. Touch it to the wheel near the edge, and roll the spine into the wheel, and carefully pull it across. It won't do a complete grind of course, just a start. As you get towards the tip, pull the handle towards you a bit. Repeat this on each side, alternately, so you don't stress the steel(or it will warp in HT).
Before doing any of this, mark your parallel lines on the blade, and grind a 45 degree bevel on both sides, not quite to those marks. This will save on belts, as you won't be shaving so much abrasive off.
You can adjust your grinds by twisting the handle, one way or the other as you grind.
One way for a lot of cheap practice, is to get lathing or lattice strips from your lumberyard. Lay out patterns on them, and do them just like you would steel. Profile, edge mark, grind the bevels, even drill the handle. It is excellent practice, and will teach you the various steps, and disipline, without a big outlay of cash for metal. Then just sell the finished product to the local kids for their lunch money. J/K. :eek:
BTW, you don't have to put handles on them.;)
Proper grinding is really all about practice, and repitition. Don't get discouraged, good grinds will happen.:D
 
Thanks Mike you answered the question:

You pull the handle back as you approach the tip.

I imagine we're not talking very much movement. Just enough to keep contact.

Also it sounds like as you go, the grind line moves up the blade towards the spine. Rather than picking a mid-point on the bevel and having the line move towards the edge.

This is probably obvious to most folks here, but a mystery process to me.

Steve
 
quote" Also it sounds like as you go, the grind line moves up the blade towards the spine. Rather than picking a mid-point on the bevel and having the line move towards the edge."

Yep, you got it. You twist the handle in whichever way you want the grind to go. When you reach that point, you twist the edge into the wheel to thin that area. Don't forget to leave plenty of meat in there during rough grinding. If you don't, when you clean up with successive finer grits, the blade will be too thin.
:eek:
You will do great. Just don't get disappointed if the first few don't come out well.
 
Mike pretty much hit it on the head,One thing that I did wrong when I put a blade to the wheel is when I got to the tip of my knife I was going past the edge of the wheel and was getting a thin spot up next to the tip.Don't bring your knife tip past the edge of the wheel.Have fun
 
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