Setting the angle for grinding a chisel

[dicktimber]

How do you set the correct angle for grinding a chisel on the bench grinder.?

I set my last one up with paper template that I stuck onto card. It had a curve at one end that you offered up to the stationary grinding wheel.
The adjacent side sat on the angle of the jig, and you adjusted the jig angle till the contour of the template matched up with the wheel.

BUT..I lost it in the move!!!!!!!

Any suggestions ?

Mike

 

[Benchwayze]

Mike,

I assume you are talking about the primary 25 deg. bevel.

I use a Tormek wet grinder, but I don't have a protractor guide for it. I just fit the chisel in the tool clamp and adjust the height, until I can eyeball that the existing bevel is at the right angle to the wheel. (Wheel stationary of course!) After I get it right, I grind.

Could you not use a chisel that has the correct bevel, in a similar way for setting your bench-grinder tool rest?

At risk of upsetting the perfectionists, as long as the primary bevel isn't 'miles' out, (1/2 a degree or more) I shouldn't worry too much. I place a lot more importance on the secondary bevel being right. And you could use a honing guide for that.

HTH

 

[gidon]

I use a very sophisticated piece of MDF with a 25 deg cut on the end!
See about 40s into my vid here:
http://uk.youtube.com/watch?v=3Hm4HiN2Lww
Cheers
Gidon

 

[Benchwayze]

Sure that would work too!
Whatever makes us happy I guess!
Cheers Gidon.

 

[Derek Willis.]

I have a Veritas grinding attachment, it gives various angles, and together with the sliding platform can grind and square any chisel or plane iron so well that only a little honing is neccessary.
Derek.

 

[dicktimber]

John,
Sorry mate..yes I am talking about the 25 deg angle, free hand grinding.
I eventually did as you suggested and used a chisel already ground and set it to that.

When I sat down and started thinking I wondered how I would set the angle if I did not have a chisel already geound?
I looked at the video on u tube, but the guy didn't explain how he managed to produce an angle of 25 deg on a curve...and ceck it was at 25 deg.

I will grind a template while it's now set up...but I still would like to know how other members set the grinding rest.

Thanks

Mike

 

[Benchwayze]

NP Mike,


As you wil be getting a hollow ground bevel then it's difficult to measure that itself. But you can measure the angle of 'approach' and a Veritas guage will be the most accurate.

All you really need is a school-protractor, to mark the angle on a piece of 3mm mdf, and then cut it to the 25 deg. Put that against the wheel, and adjust the rest to suit. As long as the rest is at the proper angle, the bevel will be close enough for 'jazz'!


I like a hollow ground bevel, others say it doesn't support the edge as well as a flat bevel. But I don't use a sledge hammer with my chisels, and I don't use them for 'darts', so I am happy!

 

[dicktimber]

john

Thank's for that.
I am from the old school....reeely old!!!
Might as well finish this chisel off ready for use???

I still use an oil stone to produce the secondary cutting angle....

I oil the stone, place the chisels back edge of the 25 deg onto the stone , then slowly lower the cutting edge.
As soon as I see oil oozing infront of the cutting edge, I know I am at 25 deg.
It's then a matter of just tilting upwards a little more to be at 30 deg, a couple or three strokes along the stone, and Bob's your Uncle.
I don't use a strop to take the burr off, just a light rub on the back of the chisel on the oil stone......

Mike

 

[gidon]

I looked at the video on u tube, but the guy didn't explain how he managed to produce an angle of 25 deg on a curve...and ceck it was at 25 deg.

You set the middle of the guide's bevel on the edge of the stone. As BW says the exact angle isn't so important but this will get you close enough.

If you want to check the angle you could make a little guide with angles notched out and then check the bevel in these notches - the Tormek comes with something like that. And here's one Axminster do:

http://www.axminster.co.uk/product.asp? ... =1&jump=44

Cheers

Gidon

 

[Benchwayze]

With the secondary bevel, it isn't how you get there that counts, so much as actually getting there.

I use waterstones now, you still use oilstones, but we should both end up with sharp edge-tools! And as my old teechur said...

The only thing you're likely to cut with blunt tools, is yourself!
I know what he meant of course.