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Tool spotting blue for scraping?

Tool
update on this for like the like 1 person who might be interested:

ended up getting dykem off the jungle website and it's definitely better than the stuff I was using - I can get better resolution.
also cobbled together a carbide grinder with a slovenian made bench grinder I got for 40$ at auction (which has a mystery orange-ish coloured wheel on it that does sharpen carbide - no idea what it is but okay) and a tilty rest I designed pretty poorly and then blasted out on the laser at work

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much to learn still but there is progress !
 
Looks good. Consider replacing the wheel cast iron and charging with diamond paste - 10 micron is what I use. I think most guys who scrape lap the ends, or at least that is strong impression I have.

Because the dept of cut is so small (can be under a tenth) without an exceptional edge the edge wants to just skip across the surface. SOP is lap the top and bottom of the piece of carbine to a mirror before making the scraper, then just lap the end to sharpen. Sharpening is frequently required. I like have a bunch of scrapers handy so grab for a fresh one then touch them in a batch. I kind of zone out and the realize its no longer any fun .... that's it telling you to sharpen.

It'll work without, don't mean suggest it's a must, but it gives an edge that is nicer to work with
 
mjautek said:
nope, but it is reversible so you can loosen both wheels by accident and wonder what the rattling noise is

is slow speed of much benefit? I see that some people make slow speed grinders but others say it doesn't matter for carbide
Click to expand...

Those slow grinders are really good for two things 1) Reducing temp with carbon steel, i.e. wood working stuff, so you don't draw the temp and 2) when diamond on steel as at high temps, i.e., high speed (temp is primary a function of the relative speeds) causes absorption of the diamond. I don't know what your wheel is but I'm not aware of any reason to slow down for diamond & carbine
 
Mcgyver said:
Looks good. Consider replacing the wheel cast iron and charging with diamond paste - 10 micron is what I use. I think most guys who scrape lap the ends, or at least that is strong impression I have.

Because the dept of cut is so small (can be under a tenth) without an exceptional edge the edge wants to just skip across the surface. SOP is lap the top and bottom of the piece of carbine to a mirror before making the scraper, then just lap the end to sharpen. Sharpening is frequently required. I like have a bunch of scrapers handy so grab for a fresh one then touch them in a batch. I kind of zone out and the realize its no longer any fun .... that's it telling you to sharpen.

It'll work without, don't mean suggest it's a must, but it gives an edge that is nicer to work with
Click to expand...

thanks for the pointer, I'll have to try a lap - the scraping marks I am making are kinda scratchy looking and I want to try to improve that... though maybe material is part of the issue? some of the scraping I've seen results in a mirror-like surface (through the scraping marks) but I suppose that's impossible to achieve with whatever cheesy cast iron this princess auto vise is made from
 
Try Terra Nova, but they can be expensive. There used to a business in the states selling 6" x 1" disks, can't remember who. Mcmaster is $42 for that disk now (US$) as a comparison.

I'd be curious to know what you find price wise
 
mjautek said:
nope, but it is reversible so you can loosen both wheels by accident and wonder what the rattling noise is

is slow speed of much benefit?
Click to expand...
That’s funny. I wish I could say I haven’t done similar things.

I’m an amateur scraper, but I’ve done a fair amount of work and have taken courses from a few guys who are very good. Before the courses I was using a Baldor with a fine diamond wheel. Wasn’t happy partly as it was too efficient at removing expensive carbide, and partly as, like you, I wasn’t getting as smooth an edge on my carbide and the work looked chicken scratched and not as predictable. Looked under magnifying almost like the carbide was getting torn out in chunks. After I found an Accufinish slow grinder it transformed my work. I sharpen way more frequently as it is quick but removes minimal material, and the edge is much nicer!

I’m as cheap as the next guy. Don’t see any reason to specifically get an Accufinish, and the company doesn’t sell em new anymore anyways. But I am a convert to slow speed grinding/honing an edge.

If you can fit a cast iron disc and charge it with diamond, you could grind hone your edges near the center of the disc for lower sfm.
 
Lucky7 said:
you could grind hone your edges near the center of the disc for lower sfm.
Click to expand...
oh that's an idea eh. I do have some diamond discs from aliexpress that I could mount up, I just don't have a 6" round of anything here at the moment

Lucky7 said:
I’m as cheap as the next guy. Don’t see any reason to specifically get an Accufinish, and the company doesn’t sell em new anymore anyways. But I am a convert to slow speed grinding/honing an edge.
Click to expand...

I,ve seen people make slow speed grinders using car window motors; I did consider that but it was much easier to convert this bench grinder ...

thanks for the ideas!
 
here's how I did it .... cheap crappy tire bench grinder with cast iron laps. I loctited collars onto the rotor and turned them in situ. It has a taper mount arrangement so I can pop the wheels off, charge them and reinstall and every things runs true. Put's a mirror finish on. The late and great Forrest Addy, master at it and many other things, just had disk on a fractional HP motor and block of wood for a rest... doesn't have to be fancy. The important thing is fine diamond lapping compound and hand lapping to a mirror the top and bottom of the carbide first.... then you lap the end to a mirror to sharpen


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Here for example is the first or second lapping of a new scraper, you can see the lapped finish is better


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yes, its 3450. No reason not to that I can think of, and the 10 micron lap cuts slow enough as it is. 6" cast iron is safe at that rpm, and by using quality material (vs say a dumbbell) and a careful process to get everything concentric, there is very little vibration. Second consideration is it's a bit more weight than the grinder is expecting. I give it a helping hand on starting to get the disk spinning before flicking on the power. It's approaching twenty years in service and has worked perfectly so I don't think the extra weight has adversely affected it
 
We have a couple of polishing tumblers with elderly split phase motors. We have always given them a yank on the belt to start. Not the safest procedure. I also have a little 6" Baldor polisher that I have to spin to start. That was likely why it was in the scrape metal bin at work where I retrieved it. I'll try getting them moving before switching now.
 
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