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Question concerning HHS tools and Carbide cutters

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Forum topic by Jack Lewis posted 03-11-2017 02:58 PM 1117 views 0 times favorited 9 replies Add to Favorites Watch
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Jack Lewis

208 posts in 913 days


03-11-2017 02:58 PM

Topic tags/keywords: hss and carbide tools

Posted this on AAW forum also.

I often read about the superior cut of HSS tools compared to Carbide. I also read that turners often make final (one more cut) with a scraper. If Carbides are nothing but scrapers, what is the difference between them and HSS tools? What justifies the choice. And it seems to me that scrapers are an inferior finish compared to a bevel ridden cut! Some opinions, both sides, please.

-- "Now we are getting no where, thanks to me"


9 replies so far

View wuddoc's profile

wuddoc

231 posts in 3553 days


#1 posted 03-11-2017 03:11 PM

Oop’s

-- Wuddoc

View Jack Lewis's profile

Jack Lewis

208 posts in 913 days


#2 posted 03-11-2017 03:21 PM

I am looking for opinions and practical user not a clinical sales talk. I don’t disagree that HSS is sharper but how sharp can a scraper be, regardless of the material it is made of? Sure it might have a burr for the very first few seconds.

-- "Now we are getting no where, thanks to me"

View LeeMills's profile

LeeMills

458 posts in 1136 days


#3 posted 03-11-2017 04:17 PM

This is just my opinion so it may have no merit.
I use conventional tools but do have two shop made carbide that I use occasionally. Most carbide cutters are flat on top and used as a scraper, however, the Hunter is “cupped” and you use it on the side rubbing the bevel so it does peel the wood instead of scraping. I will post a link to John Lucas’s video on the Hunter.

For me I do get an inferior finish with the carbide. One caveat may be in spindle work where you run into a knot or wild grain. Even with a sharp skew it may be impossible to get a clean cut due to changes in grain direction. In that case a very light scraping may give a better result.

As far as finishing cuts on a bowl the very last cuts may be with a scraper, but not held flat. The scraper is held at 45 -60* and you are really making a sheer cut. This is about the same angle the wing of your bowl gouge would be if you were making a sheer cut with it. For the interior of bowls the scraper would be radiused and for the outside it would be straight. Exterior bowl “skews” come in a L or R depending on which direction you are cutting in. Either cut is very controlled and deliberate. IIRC Lyle Jamieson stated you almost forget to breath and John Jordan stated that it was difficult to talk and make the cut at the same time. Typically the scraper is used to clean up the very minor tool marks from the gouges.

In short, I use carbide sometimes for roughing bowls or platters but not a lot else. The cost of carbide is fairly reasonable as long as you make your own handle. One Easy tool is about $120 retail and the replacement cutter is about $20. In my way of thinking they want $100 for a wooden handle and a bit of square bar.
https://www.youtube.com/watch?v=nfp2kvhH6Mo

-- We cannot solve our problems with the same thinking we used when we created them. Albert Einstein

View Markmh1's profile

Markmh1

62 posts in 279 days


#4 posted 03-11-2017 05:33 PM

Carbide has come quite a way. I too, am sick of the sales drivel but in some cases, it is informative.

Even a few years ago, carbide cutting angles were negative or neutral. With “new” developments in micro-grain C4 carbide, that isn’t so brittle, positive cutting angles can be used and with acceptable life.

Forrest saw blades have a positive angle and hold up quite well. Remember the B&D Piranah (sp?) saw blades? A fellow was lucky to unwrap one of those without chipping. An example of radically positive cutter geometry coupled with carbide unable to hold up with this minimum support.

Without examining your cutters, perhaps your cutting angle, coupled with the relief, is different on the carbide. It’s also tough getting a smooth edge on the carbide.
Under magnification, the cutting edge on carbide can look like a saw. With HSS, it grinds smoother, and there’s usually “the artist touch” with a fine India stone. This can make quite a difference.

I do hope this makes some sense.

Mark

View TheDane's profile

TheDane

5328 posts in 3498 days


#5 posted 03-11-2017 06:39 PM

Your HSS scrapers have (or should have) a tiny hook that is actually the cutting surface.

If you think about old-fashioned card-scrapers, if they were properly sharpened they would produce fine, angel-hair shavings from a flat surface.

Same principle applies to HSS turning scrapers … if sharpened properly, they have a tiny hook (or burr) that produces shavings. If you learn how to sharpen then shear-scrape with an HSS tool, you can produce a surface that requires little or no sanding. If they are producing sawdust, they are dull and need sharpening.

I have never seen a carbide cutter that you can raise a burr on … hence, they are ‘dull’ by HSS standards.

I grind my HSS scrapers to about 25 or 30 degrees, flatten the top (non-bevel side) with a honing stone, then use a burnisher at about a 5 degree angle to raise the burr. When it starts to dull, I knock the burr off the top with the stone and re-burnish … you can do this many times before you have to make another trip to the grinder. It takes a while to learn this technique, but once you have it, you can shear-scrape to produce amazing results.

Full disclosure: The technique I described is one that is taught by Alan Lacer ( http://www.alanlacer.com )

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View Lazyman's profile

Lazyman

1503 posts in 1223 days


#6 posted 03-11-2017 07:04 PM

Gerry, Doc green has a pretty good explanation of putting a bur on a scraper here. Is this similar to the method you use?

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View papadan's profile

papadan

3584 posts in 3204 days


#7 posted 03-11-2017 07:26 PM

Short of a roughing gouge, most all of my outside turning is done with a Sorby oval skew. I use a small bowl gouge for roughing out the inside of bowls and vases but then use my carbide tipped tools for finishing the inside. My main carbide is a Sorby, I don’t know the name of it but it has the crooked end which is good for inside turning. I do have a few HSS tips for it that I made myself for special piece turnings. I am completely self taught and happened to start with a skew which a lot of people think is a hard tool to use. I never use a scraper that I am aware of.

View Wildwood's profile

Wildwood

2186 posts in 1970 days


#8 posted 03-11-2017 07:48 PM

This site about the cheapest will find for carbide cutters but shipping expensive. Have to pay attention because some cutters require you to buy 5 packs of 5 and other type cutters require you to buy 10 packs of 10. You better measure your cutter & screw hold before ordering too!

http://www.carbidedepot.com/wood-turning.aspx

If use carbide cutters a lot for both finishing & roughing might make sense. Sharpening with diamond card files let you tough up an edge but eventually need to replace your cutters.

Bought a Sorby shear scraper with one handle but bought both type cutters, but do better with HSS gouges & scrappers when shear scraping. Came with instructions for use and sharpening with a card file. Like said before dull carbide needs replacing.

http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=packard&Category_Code=tools-srby-shear

Think HSS tools give you bigger bang for the buck but JMHO!

-- Bill

View TheDane's profile

TheDane

5328 posts in 3498 days


#9 posted 03-11-2017 09:41 PM

Gerry, Doc green has a pretty good explanation of putting a bur on a scraper here. Is this similar to the method you use?

- Lazyman

Very similar. I have had a couple of workshops with Alan Lacer, and the method I use is what he teaches … grind first, hone/flatten the top, and burnish the cutting edge.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

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