Thread: Motorised Chisel back flattening - taking the grunt work out of it

Thats the sort of thing i meant with the orbital sander. Ising rhe sander to osilate a chisel over a flat bed with paper on it

Looking good

Dave TTC
Turning Wood Into Art

Originally Posted by FenceFurniture

The solution was staring us in the face all along.

Three hours (including thinking time) and I came up with this, all from scrap (more or less).

VERY VERY well done!

Ingenious. Though I think need video.

Thats bloody awesome. After all these years flattening chisels on oil stones, then water stones and now diamonds...it never even entered my mind of jigging up a device to do the hard yakka for me. I had nothing to do tomorrow so i was going to spend it fettling a few planes except for the flattening of the irons, but now i think i might build something like this instead.

Ok I want to see were this goes
Will there be a float to raise funds for production lol

Clever. Give that man a Nobel prize.

Yes, dubbing will be the challenge.

Now you stirred my neurones into action....

For lapping my metal scrapers (tungsten carbide tips), along with a few of the scraper class aprticipants, I built myself a lapping machine.
It is essentially a 4-pole (1440rpm) motor with a cast iron wheel mounted on its spindle. In my case 5" deiameter on a 1/3 HP motor.
We charge the face of the wheel (not the circumference) with diamond paste by rolling the paste on with a ball bearing on a handle - pressing it into the spinning wheel hard.
Then we hold the scraping tool edge agaisnt the cast iron wheel and it polishes the cutting edge.....

I have never even given a thought to using this machine for anything else. Tomorrow I'll hold a chisel back against the wheel and see what happens.
I have a gut feeling the speed is too high, but that might just mean trying it on a slower motor... If heat is created at the contact point of the steel with the diamonds, the diamond (which is of course pure carbon!) is absorbed into the steel (increasing the steel's carbon content). That's why you shouldn't grind steel with diamond wheels at high speed.

I'll be very interested in the result. Failing this experiment due to surface speed, I can always put a cast iron wheel in my lathe and try it there with variable speed, to determine at what point it fails....

diamond_lap.jpg

Hi Joe

We tried a similar thing when we were at fletty's last Sunday, with a Worksharp 3000 (pic courtesy of crowie) fitted with a diamond lapping disc. Not too bad, but the disc wasn't aggressive enough (260 grit), and the machine is about $450 plus consumables.

We also tried a Sorby ProEdge, which is essentially a linisher. The linisher dubbed the edges of the chisel quite noticeably, possibly due to the cloth belt rising up, or maybe because the join in the belt was a little high.

Pittwater Pete is continuing to play with the Worksharp, but feels the 6" disc is too small. the other thing about a spinning disc is that the rim is going at a much faster speed than the centre which is where the business end to be flattened is, but the full blade needs to be on the disc to ensure registration.

It will be very interesting to see your results. Have you got a VFD you could attach to slow it down?

Seeing your recipro saw lying there reminded me - I briefly flirted with an idea for that moving the plate back and forth, but quickly realised I didn't have enough hands, and building something to hold the saw still would be tricky. It would also be too fast with it's recipro motion (like me, I'm told ).

With the device I built yesterday I still expect that there will be some dubbing of the leading edge, but that can be ground back (and would be anyway in the normal course of the rehab process).

Originally Posted by FenceFurniture

We also tried a Sorby ProEdge, which is essentially a linisher. The linisher dubbed the edges of the chisel quite noticeably, possibly due to the cloth belt rising up, or maybe because the join in the belt was a little high.

One currently available, but expensive, solution that we haven't yet tried is the diamond belt option on the ProEdge. I'll be in Sydney this week so I'll pick up a diamond belt and give it a go. One thing I noticed last week with the non-diamond belts on the ProEdge, is that the 'overlapped join' belts seem to have a major dubbing effect so hopefully the diamond belt is butt joined or, better still, continuous!
The other 2 variations I will try are a foot switch to enable starting with the chisel already on the belt, and reversing the chisel so that any dubbing effect is NOT on the cutting edge?

fletty

What grit is the horrendously expensive belt?

Knife makers do this kind of thing with every knife. They make themselves a "noob grinder" and a sliding carriage that grinds the entire length of the knife completely flat. (or on angles or specific curves).

They can be bought at Gameco or hand made or by searching for open source plans (there are many available). Belts specifically for grinding and shaping metals are sold by Gameco as well.

Knife guys go all out on theirs, but for this purpose one can be make of mdf and be perfectly serviceable.

MDF would only be ok for dry use. I used UHMW Polyethylene (aka breadboard material) because it slips well, and i had some .

Fletty, wodjie's post reminded me that Corin (who runs Gameco) lives in Picton......

This is the list of belts on page 5 and what is best: http://gameco.com.au/wp-content/file...rinder-1.0.pdf

They are quite cheap. Setting up a grinder is a bit of a challenge, but it's really the belts for grinding and getting rid of the join that is the headache. Grab some of those and bodge up a pseudo upside down belt sander....