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How Sharp are Carbide Insert SHIMS? Machinists, never used these so I need help! Answered

I have a few secret upcoming projects in which I plan on using carbide turning inserts. Both for woodworking and metalworking projects, but not machining - their intended use.

I was wondering if anyone has any experience using these. I was looking at buying square inserts, but I can find only shims like this: https://www.ebay.com/itm/292307002360 . Do you know if these are even slightly sharp? I mean, can I scrape wood with them with my hand, not in a milling cutter? Will they cut wood?

If not, I was thinking about getting something like this: https://www.ebay.com/itm/173054401114 or https://www.ebay.com/itm/391346000853

How sharp actually are these actual carbide inserts? Will these be able to scrape hardwood if I for example, hold them with pliers and scrap them across wood?



As always an excellent video !

Please tell how you place it

OPERATING SYSTEM would lock me out the moment I click Add_Images :-(


Best Answer 4 months ago

What exactly do you intend to use them for?

And by "cut" what exactly do you mean?

they generally are sharp enough that if you were to slide them along your skin with pressure they'll likely lacerate your skin. If you poke yourself with them on a corner, they will likely puncture your skin (and similarly puncture most hardwoods) They will be sharp-edged enough to be used as a scraping tool on hardwood, but due to the high angle edge, they will be unlikely to compete with a low angle chisel in terms of actually "cutting" wood. I use simply paint scrapers, filed for a nice clean 90 degree edge for scraping wood (finish work). Being essentially just plain steel or slightly hardened steel, they dull quickly, so carbide should take considerably longer to dull. I do have one carbide fitted paint scraper and it holds edge pretty well but eventually wood will dull most any edge. They can also chip easily if dropped onto stone or concrete. (I know because I chipped the blade on my carbide fitted paint scraper by dropping it)

Do you intend to use this tool as some sort of hand gouge or for surface finish? for finish I'd say go for it. In fact, unless you *need that small a size, I'd suggest looking for a paint scraper that has carbide inserts. For manual channelling? idk... I'd be more inclined to use a narrow throated chisel.

Thanks. Pretty much what I wanted to hear. I will buy the shims and try to sharpen then with Diamond cutoff wheels, they look like they have the most carbide for the $.

I hate not being able to edit my posts...

"I use simply paint scrapers" => "I use *simple* paint scrapers"

They are not very sharp. For wood (or soft metals) you really want highly polished negative rake inserts like CCGT

I realize this is cheap carbide that won't hold an edge as long but I'm fine with that.