Putting back bevel using Veritas Jig

Does anyone know how I can use the Veritas honing jig and bevel guide to put a 5 degree back bevel on my blade (which is honed at 20 degrees)? No matter how hard I try to figure it out, I just dont have the head for geometry. Is it even possible using these tools or is there some other way?

Thanks

Bob

Reply to
Bob
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Let me guess - you threw away the instructions!

The roller is on a axle that is offset. If the axle is rotated, the angle of the blade is changed by several degrees. I haven't used it in a while, but IIRC, just grab the ends of the axle, push or pull it one way and turn it 90 or 180 degrees. If you look carefully, you'll see what's happening.

Mike

Reply to
Michael Daly

My question is not how to use the guide. I understand that and use it all the time. My question is how to put a 5 degree back bevel on a blade using the 15, 20, 25, 30, and 35 degree settings. The blade I have is honed at 20 degrees its front--now what guide angle do I use to take off 5 degrees from the back-- see?

Bob

Reply to
Bob

you can't. I have that same guide, Bob. For the 5 degree back bevel you'll have the the tool on it's back, elevated a mere 5 degrees.. the guide can't be used for that...unless you place the guide on the table and the blade on a stone or other elevated sharpening surface such as sandpaper on an appropriately high block.

dave

Bob wrote:

Reply to
Bay Area Dave

By rotating the axle, you can change the angle by a couple of degrees IIRC, not a full 5 degrees. I've found it's easiest to just do the back bevel by hand. Lee's book shows putting a small block under the blade a certain distance from the edge and that equates to 5 degrees. I forget the details but I seem to remember something about "the law of 60"? If you don't have the book, lemme know and I can dig out the specifics for you. Cheers, cc

Reply to
James Cubby Culbertson

Reply to
Daniel

Bob, If you've got a blade honed at 20 degrees, you should be able to set the guide to 25 degrees and set the blade in with the bevel side up. Raise the blade in the guide and the flat side of the blade should be 5 degrees off the bottom. Denny

Does anyone know how I can use the Veritas honing jig and bevel guide to put a 5 degree back bevel on my blade (which is honed at 20 degrees)? No matter how hard I try to figure it out, I just dont have the head for geometry. Is it even possible using these tools or is there some other way?

Thanks

Bob

Reply to
Denny

Thanks for all the answers. Ive since realized that the poster who said it cant be done in the normal fashion with the Veritas jig was right. The problem is that the jig can't go far enough back on the blade to lower it enough. Otherwise, I could use the 25 degree slot (for my primary 20 blade) in the bevel guide.

I have seen the description for a 3/32" piece of wood placed 2" from front of blade as a guide. I tried this last night using tape to hold it in place. The tape worked terribly, but it did put a 5 degree bevel on the blade. Now if I could figure out a better way of afixing the blade to the jig... Im going to work on this because I will need to do this frequesntly on my block plane.

bob

Reply to
Bob

The way I've been told to do it is to place a steel ruler or shim along the edge of your honing surface. Lay the blade perpendicular to the ruler and hone the back using a side to side motion. I haven't tried it yet but that's the way I planned to try it. However, the above method of placing the wheel of the jig on the table instead of the stone sounds plausible.* I don't know if that will work but it may be worth a try.

Cheers, Mike

*This approach may be difficult if the goal is to make a 5 degree back bevel. My goal will simply be to simplify the process of polishing the very end of the back.

Reply to
Mike

Just curious, why a back bevel on a block plane?

Reply to
Lawrence Wasserman

You might try double sided carpet tape (not sure if that's what you used or not). Stuff's pretty sticky. I think that's what I used the last time I back beveled my block plane's blade.

Cheers, cc

Reply to
James Cubby Culbertson

On a standard block plane, by putting a back bevel on it, you effectively lower it's cutting angle. A standard 25 degree bevel on a standard block plane produces a 45 degree cutting angle (voila, a small smoother!). By putting a 10 degree back bevel on it, you effectively reduce this to 35 degrees. Cheers, cc

Reply to
James Cubby Culbertson

No.

Reply to
CW

Not exactly. To get 35 degree w/ 20 degree ramp your primary bevel would have to be 15 degree as block planes are bevel up. The back bevel is used often with low angle primary bevels to A) strengthen the edge and B) to increase the clearance angle.

Reply to
jev

My terminology isn't quite correct, nor my math. I dug out my "Complete Guide to Sharpening" by Leonard Lee. Here's what he has to say about it:

"You can easily grind and hone a 15 degree bevel on the blade and then put a 10 degree back bevel on the face of the blade (refers to his diagram on P. 84). This would still leave you with a 25 degree included angle, but you would now have reduced your cutting angle from

45 degrees to 35 degrees. You are still left with a 10 degree relief angle, which is perfectly adequate for block-plane use. Possibly more significant, you have sharpened the blade of your standard block plane in a manner that will give you a lower cutting angle than someone who sharpens a low-angle block plane in a standard fashion (12 degrees bed angle plus 25 degree bevel, a total of 37 degrees)."

I highly recommend this book. Cheers, cc

Reply to
James Cubby Culbertson

In this case, the back bevel has nothing to do with the cutting angle. It is the 15 degree sharpening angle that is lowering the cutting angle. The back bevel is used simply to give the edge strength.

Reply to
CW

I don't see this the same way. To me, it appears that the cutting angle of a normal bevel-up block plane will always be the sum of the bed angle plus the bevel angle. Putting a back bevel on a block plane blade would decrease the clearance angle. I don't see how this would be useful, maybe there is some circumstance where it would be.

Or does back bevel mean something different? I think of a "back bevel" as a short bevel on the "back" of the iron, i.e. the side that is normally flat.

Reply to
Lawrence Wasserman

I see said the blind man! I was under the impression from his book that by combining the two, the angle is effectively lowered. I'm still trying to sort out the geometries of plane blades! cc

Reply to
James "Cubby" Culbertson

It is as you see it. Decreasing the clearence makes for a stronger edge.

Reply to
CW

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