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My "Dormek" Sharpening System

Posted: Sun Jan 05, 2020 8:28 pm
by Morecowbell
As I've continued to look at sharpening methods I remembered John's comment about his Grizzly Tormek knock-off, so I started looking at it along with a few others, then suddenly remembered that I had had something very similar as a kid, the Delta Wet/Dry grinder - I had used it only a few times then given up, there was no way to keep a blade or chisel straight on the wheel with the miter gauge...and I think that's why the magic of the Tormek system hit me, that sliding pivot holder is genius! So now I'm wondering if I still have the Delta - I dug around a bit and found it in a dark recess in the basement. So then I started wondering if I could add the Tormek holder system to it...after some research it seemed possible but expensive and complicated...and then I thought of a pretty simple way of making one. The first pic is the Delta grinder - the table for the big wheel is pretty sturdy, square, and has good adjustments. The second pic is the start of the holder, the third is the rod arrangement. I had the plexiglass, got the 3/8" rod and bushings at Menards.

Re: My "Dormek" Sharpening System

Posted: Sun Jan 05, 2020 8:38 pm
by Morecowbell
I tried to keep everything square as I went but was prepared for a lot of fiddling and/or disappointment - to my great surprise it lined up really well and worked like a charm. And I can say for certain that I've never had a plane blade sharpened so uniformly. So now I'm cautiously optimistic that after 30 years, I can put this machine to good use :-)

Re: My "Dormek" Sharpening System

Posted: Mon Jan 06, 2020 9:13 am
by MaineGeezer
Excellent!

You have inspired me to take another look at a small powered grindstone that Ive had sitting around for a very long time. Your observation that the key to the whole thing is a good precise guide for the tool is obvious once you say it, but it certainly wasn't obvious to me. I'll have to see what I can come up with.

Re: My "Dormek" Sharpening System

Posted: Mon Jan 06, 2020 9:56 am
by tippie53
great thread
Nice to share and you are correct that the one thing that is critical is holding that angle constant. Unless you do this daily you can't trust your hand to be square and true.
I love my grizzly tomek copy
jh

Re: My "Dormek" Sharpening System

Posted: Mon Jan 06, 2020 10:27 am
by Diane Kauffmds
Looks great

Re: My "Dormek" Sharpening System

Posted: Mon Jan 06, 2020 11:42 am
by MaineGeezer
You can't do it reliably by eye even if you do it every day.

Back in 1952 a guy named Leo J. St.Clair wrote a book called "The Design and Use of Cutting Tools." It's basically a 400-page analysis of the geometry of lathe toolbits. In it he stresses the importance of correct angles, and he did an experiment. He went to a machine shop and asked 20 machinists to grind a 6 degree relief angle on a piece of steel. Here is what he got:
one 2 degree angle
one 3 degree angle
two 4 degree angle
two 5 degree angle
three 6 degree angle
one 7 degree angle
two 8 degree angle
two 9 degree angle
one 10 degree ange
three 11 degree angle
one 14 degree angle
one 18 degree angle
Only one of the 20 machinists used a protractor to actually measure the angle he was grinding. Presumably that is one of the three correct 6 degree results. Considering only the 19 ground by estimation, 17 out of 19 got it wrong.

So...if you think you're putting a 25 degree bevel on a chisel by eye...you probably aren't!

Re: My "Dormek" Sharpening System

Posted: Mon Jan 06, 2020 12:14 pm
by Morecowbell
Gotta hand it to whoever came up with that guide & holder system, it really changes the game. I honestly used to hollow grind plane irons on a 6" grinder, freehand - then water stone, again freehand. If you do it enough you can get a serviceable edge, but nothing like this. Tormek also has another ingenious attachment for doing kitchen knives, will try to knock that off next weekend!

John - have you ever had to "dress" your wheel? Wondering if that's something I need to be prepared to do.

Re: My "Dormek" Sharpening System

Posted: Mon Jan 06, 2020 12:16 pm
by Morecowbell
Diane - if you look closely you might recognize the clamps!!!

Re: My "Dormek" Sharpening System

Posted: Mon Jan 06, 2020 12:31 pm
by tippie53
as a machinist I would use a sine vice for angle grinding.
Here is a tip , and I will get pics next time I sharpen
you can make a set tool that will set your chisel into the holder. In most chisels I use a 60 degree angle

May not be dead on but gets you in the ball part. When I sharpen I do a main angle with a secondary angle for wood work so it allows the chisel to cut up and rocks off the angle for clean back out cuts.

I use the wet stone then use the angle roller guide on the Japanese water stones. If your chisel won't dry shave you just have a pretty piece of metal

Re: My "Dormek" Sharpening System

Posted: Tue Jan 07, 2020 1:51 am
by Stray Feathers
I have had a Delta Sharpening Centre 23-710 for years and it is good but has limitations.
(https://www.finewoodworking.com/2006/02 ... 710-review)
You have inspired me to look at it more closely to see if I can get or make a better rest for chisels (especially) and plane irons, particularly for the dry wheel. (The sliding rest is pretty good on the wet wheel, as long as the wheel is trued.) I have wondered about third party attachments but have not looked into them, thinking it might be a bit fiddly.