Thread: An idea for a contact grinder.

Man if i had access to a CNC id be all over that.....fast, accurate and the ability to do just about everything shy of finish grinding......

Originally Posted by jfk742

You’re edge thickness should end up in the .005” area. I would think you could go slightly less than 2mm for ht.

You could set your drum sander up to do final sanding pretty easily I would think. A machinists vise with some flat stock and a series of spacers may work to keep from getting wavy. As you get close to final thickness free hand it to blend in anything around the shoulder since that may be a problem area with the swoop you’ll need to do to get the shoulder right.

I should be up and running in a month or two for heat treating so if you want to experiment with different thicknesses for heat treating we could probably get something figured out so you’re not spending all your time on finish grinding. Finish grinding is what took me the longest. There seems to generally be enough thickness to take care of any warping due to ht when grinding post ht. Smiling blades lend themselves to being slightly warped and still being able to maintain an even bevel and easy honing.

I'm really looking forward to you getting your setup running! Another member up north has offered his HT services in the interim. It's gonna depend on how long it takes me to actually jump on the grinding. I keep rethinking my approach!

Originally Posted by 6cuda6

Man if i had access to a CNC id be all over that.....fast, accurate and the ability to do just about everything shy of finish grinding......

It's where I want to be, but the learning curve is substantial!

Out of curiosity, I just checked the Roberts razor I'm shamelessly copying.

It looks like the grind on it was done on the flat side of the stone for roughing, then hollow after heat treat. It's slightly concave. It's also not the traditional T shaped rattler. It's maybe three times thicker just under the lip of the spine than at the edge.

Also, I’ve mentioned it a couple times, but this is the RSO I made to see if my drum sander setup was up to the task.



Completely unusable for a variety of reasons, not least of which being it’s made from steel I found in a castoff bin and was part of a very large sheet.

But the spine is wrecked and the thickness is wrong and it’s not thick enough for the blade width. But, it told me this was at least a semi-viable venture and it cost nothing to do.

Well its a sweet looking replica of what's to come, Zac.
I really dig those ol 1700 razors.

Originally Posted by outback

Well its a sweet looking replica of what's to come, Zac.
I really dig those ol 1700 razors.

This one's actually from the very early 1800's and persisted for quite some time -- 1830's at least. But it wears its lineage right on the sleeve and isn't much of a break from the past at all.

Did you try setting a bevel on the rso? Only reason I ask is it will show you where you need to grind more, was super helpful for me to get my bevel and those the steel behind the edge even and any waves out of the hollows, or flats in your case.

Originally Posted by Voidmonster

Oh, I forgot to add the things I used here:

'Alternative Ivory' from Masecraft

#80 drill bits for the small pins and #77 bits for the one large one

30 gauge sterling silver wire for the little pins
24 gauge sterling silver wire for the big pin

FYI, sterling silver wire in these gauges is very cheap. It's a TINY amount! And even for all those tiny pins, with some losses, I used less than half of what I bought. 12 inches of both sizes cost less than a dollar.

IF you are not yet using a peck type feed on your drill, try it. What that does is brings swarf to the surface and allows a cooler drilling. Ok, "peck drilling" is setting the down feed to retract every so often and the go back to depth and finishing the holes. A little bit more time but less damage to the work pieces. Some CNC mills have the sotware to do it installed by the maker. Often use in PC board fab and electronics work.
YMV ~Richard

Originally Posted by jfk742

Did you try setting a bevel on the rso? Only reason I ask is it will show you where you need to grind more, was super helpful for me to get my bevel and those the steel behind the edge even and any waves out of the hollows, or flats in your case.

I didn't try that. More likely than not, it's pretty screwed up. I took a couple large bits out of the spine at the beginning of the grinding and somehow they just kept sliding the wrong way -- which was the major inspiration for my jig idea.

Originally Posted by Geezer

IF you are not yet using a peck type feed on your drill, try it. What that does is brings swarf to the surface and allows a cooler drilling. Ok, "peck drilling" is setting the down feed to retract every so often and the go back to depth and finishing the holes. A little bit more time but less damage to the work pieces. Some CNC mills have the sotware to do it installed by the maker. Often use in PC board fab and electronics work.
YMV ~Richard

I really should have thought of that. All the work was done on my extremely manual drill press, which unfortunately has only 4 speeds "slowest, not as slow, pretty fast, and fast as it'll go". Presumably the original pulleys had rated speeds, but the drill was born well before I was and I suspect the manual was lost before I showed up too. I've been thinking about replacing the replacement motor with a DC induction motor from a treadmill and adding a tachometer. It'd be very nice to have continuously variable speed and a tachometer. I've killed so many drill bits working on metal.

Have you tried a Dremmel in the press they make? It can really be slowed down and it should chuck up those tiny bits well....