Thread: Surface grinding & beer

Does it have to be on a surface grinder, Ken? I could do it on my 5" angle grinder no sweat. Or, if you prefer, on water stones up to 8000 grit. The surface grinder will have to wait a couple of months.

Greg

Originally Posted by neksmerj

I'm happy to pay someone or ply them with beer.

Sounds like a good deal.. are you going to the scraping re-union? if so you could post them to me, and pick them up at the scrapefest-reunion.


Regards
Ray

Hi Greg, or should I say, "Chairman of the Board".

Thank you for your offer. I reckon a surface grinder with magnetic table is the go. The first blade I has sharpened was done this way with great precision, in addition, the coolant kept the blade at the correct temper. It needs to be razor sharp. I have grinders here, but wouldn't tackle it.

Ray, maybe I should attend the next scrapping meeting and catch up with you guys.

My free days are restricted.

Ken

Originally Posted by neksmerj

I've made up a wedge shaped holder to hold the blade, so it should be an easy job. I don't have a surface grinder.

Ken

A linisher would do that perfectly.

Then finish off with an oil stone.

Rob

Ken

I'd be the most local guy with a surface grinder with coolant. I'm a little hard to catch up with, but I should be in most of the weekend. I'm taking a break from my day job, to catch up on my other jobs. Provided its a cold 6 pack, we should have that sorted by the bottom of the second can. You should have my email.

Phil.

Hi Phil,

Have sent you a PM.

Ken

I must thank Machtool for volunteering to sharpen some blades for me with his surface grinder.

There's a small problem, because the blade is so thin at the cutting edge, it deflects away from the grinding wheel.

What suggestions do members have in order to get the cutting edge as sharp as possible, after surfacing grinding?

One silly thought I had was to mount a circular stone on a gramophone turntable, rig up the blade to the arm, and lower it onto the rotating stone.

I see Target have a small portable turntable on sale at present for $49.

I need something that is repeatable so I can give the blade a lick when it gets dull.

Your thoughts?

Ken

"What suggestions do members have in order to get the cutting edge as sharp as possible, after surfacing grinding?"

Maybe you could do what a barber does to his cut-throat razor, sharpen with a leather strop.

john

Hi Ken,

The answer to that would provoke dozens of replies and heated argument over in the hand tool sections of the forum where there are people who take sharpening to a whole other level.. but the REALLY crazy people for sharpening are the straight razor people, look for razor forums and that's all they ever seem to talk about..

When the plane blades come off the surface grinder, there is a "wire edge" that's a small burr that need to be taken off. The grinding is done with the blade edge fully supported and wheel running parallel to the edge.

Then the burr is taken off with a 5000 grit Shapton, although Josh thinks Bester is better than Shapton..



This is taking off the grinding burr. A few careful swipes on either side is all it takes, and that's razor sharp, it will pop hairs off your arm.

For the forum blades we stop at that stage, those who want to go to the next level with flattening and polishing the back and perhaps a secondary bevel can do it themselves..

And handling stuff this is dangerous, you can easily get a very nasty cut, which is why I got that strippable hot dip stuff



Regards
Ray

Hi Ray,

Thanks for your suggestions, what on earth is Shapton and Besser?

Forgive my ignorance, I'm only an ex inguneer.

Ken

Hi Ken,

Try a google search with site:woodworkforums.com Shapton

You'll find plenty of discussion..

Regards
Ray

PS.. Bester, not Besser.. ( slip of the keyboard ) try googling site:woodworkforums.com Bester

PPS.. Waterstone testing, the results. Part I. « Tools from Japan blog. Be sure to follow the links at the to the other parts of the tests..

PPPS.. I've used the 3M micro abrasive film on granite surface plate, that's pretty effective, down to fractions of a micron...

PPPPS... another idea, google "scary sharp" basically wet and dry on glass, works ok for some steels..

I have a few thoughts, Grinding conventional would help, you can see it Ken's first post, third Pic. The jig, if I orient that normal, I'm going to plow into the heads of those socket head screws. So I plunge ground the one test piece. T & C grinder might be better, but the edge is so thin it burns even under coolant.

Does any one know how power hack saw blades are heat treated? I was under the impression that only the teeth were induction hardened, giving the shank some flexibility.

The angle doesn't help, it's waffer thin. You can easily deflect the thin end under light finger pressure. I cant see that standing up under cutting forces. I think it will just fold over.

Phil.

Originally Posted by RayG

but the REALLY crazy people for sharpening are the straight razor people, look for razor forums and that's all they ever seem to talk about..

Have you ever shaved with a cut throat? Best shave ever, its fantastic.....but on the flip side.....have you ever shave with only a "sharp", not razor sharp cut throat? It would have to be one of the worst things i have ever tried to do.......

I would second the use of a very fine stone and then a leather strop.

Hi Phil,
Couldn't you add another piece of say 5mm plate under the blade so it is supported all the way to the edge? (might be better to make a new jig with a surface ground top surface thats 1/2"(?) longer)*

I think most power hacksaw blades are pretty hard all the way through. (Bi-metal of course are different.)
Maybe the teeth are harder than the rest but the ones I have used snap like a carrot. (but maybe thats just the steel the are made from?)

As far as the edge goes, maybe this is the primary bevel?


Stuart

*No changed my mind about that, if its a two piece jig you could slot the holes on the top part so as the blade was sharpened in the future you could slide it back and not be grinding away the jig.