Question concerning HHS tools and Carbide cutters

[jacklewis]

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.

 

[Mike Johnson]

My Kung Fu is far superior to your Kung Fu, really comes down to tool technique
preparing the wood item for final finishing. You could hand a sharpened screw driver
to an accomplished wood turner and they could most likely finish the same item quicker
then a novice with all of the best tools available. Every wood turner is going to use a
method which works best for them, carbon steel, HSS, carbide tools, cheap sandpaper,
expensive sandpaper, wood sealers, abrasive and polishing compounds.

The same two individuals could be provided the same finish to apply to an item and end up
with completely different results. Each individual develops the skills and knowledge to properly
apply different finishes over time. Each individual works with the tools and the work space available
to properly apply the different types of finishes available to them.

 

[odie]

My Kung Fu is far superior to your Kung Fu, really comes down to tool technique
preparing the wood item for final finishing. You could hand a sharpened screw driver
to an accomplished wood turner and they could most likely finish the same item quicker
then a novice with all of the best tools available. Every wood turner is going to use a
method which works best for them, carbon steel, HSS, carbide tools, cheap sandpaper,
expensive sandpaper, wood sealers, abrasive and polishing compounds.

The same two individuals could be provided the same finish to apply to an item and end up
with completely different results. Each individual develops the skills and knowledge to properly
apply different finishes over time. Each individual works with the tools and the work space available
to properly apply the different types of finishes available to them.

Well, Mike just gave one of the greater responses to an often asked question.

In the end......it's all about the results, and not about what anyone uses to achieve those results.

To my thinking, a sharp edge can be put on any type of commonly used steels........it's all about how the user applies that edge.

ko

 

[Dennis J Gooding]

A possible clarification. There seems to be two issues here: Cutting versus Scraping and HSS versus Carbide. Both turning techniques have their place in woodturning and any controversy about it would be regarding the degree applicability of each to any given task. Both HSS and Carbide are used for both cutting and scraping tools, although Carbide is less frequently used for cutting tools in woodturning.

 

[hockenbery]

In woodturning there are many variables. Grain orientation, grain figure, size of the work, type and hardness of the wood.

With scrapers there are several variables too: size of of the scraper, shear scraping at a high angle gives different result that a horizontal edge and a negative rake gives different results too.

grain orientation is a big consideration. In spindle work i don't scrape. I'm not real good with a skew but I sand my skew surfaces with 320 and 400. My friend Temple who is real good with a skew always asks if I'm roughing them up to paint them. Sometimes I have to sand the bottom of cove I cut with a spindle gouge with 220.

In face grain turnings, bowls and platters, size and hardness of the wood matters.
Exotics a scraper often gives better results than a cutting tool.

I turn mostly domestic hardwoods often with a natural edge.
Some of the variables are size, wet/dry, natural edge, hardness of the wood

Generally bowls less 12" diameter are much less demanding of skills and tools than are bowls larger than 15". I rarely use a scraper on the smaller bowls beyond some shear scraping on the outside with the bowl gouge.
On the larger bowls I do 15-16" maybe an 18" once in a while I probably use a scraper on 25%
I just miss a smooth surface on the inside bottom and while I might get it with repeated tries with the bowl gouge there isn't enough wood left to keep trying so I use a round nose scraper with a horizontal scrape. The scraper I use is 1 1/4" wide HSS. This lets me smooth the curve of any bumps or slightly torn grain. A narrow tool doesn't smooth the curves as well for me.

When I turn green wood I don't sand on the lathe. So my goal is a surface I can sand with 220 after some spot sanding with 180. A gouge gives me this surface most of the time. Again i sometime use a scraper on the bottom middle of the large ones.

My view is biased because I'm not very good with scrapers and I do a pretty good job with a gouge.
Also the carbides vary a lot. The smaller ones used horizontally work to a point and the learning curve is brief. The draw back is that after 2-3 bowls that is as good as you get with those tools. Might need to turn 5-50 bowls with gouge to get one that good then they keep getting better.

If you learn to turn with a sideground gouge in a good quality class you will do better surfaces on native hardwoods with the gouge than you can get with a horizontal carbide.

Also some carbides can be cutting tools too. That adds a whole,other dimension.

 

[Mike Johnson]

Now if we can just agree on whether the Egyptians used cutting or scraping copper tools to build the pyramids.
I just giggle when I hear the explanation of copper tools being used to cut 200 ton granite stones.

 

[hockenbery]

Square edge is another item. I always use a shear scrape to smooth the surface.
Here I use an Al Stirt style scraper an 1 1/4 wide. Been a long time since I've done any of these.

 

[Tom Albrecht]

Square edge is another item. I always use a shear scrape to smooth the surface.
Here I use an Al Stirt style scraper an 1 1/4 wide. Been a long time since I've done any of these.

Ya know Al, you made a reference to Stirt a few weeks back. I checked him out, bought his video, and then bought his "Scrapers", which he uses like no one else I've seen. I am sure you already know this, but he even sells them with a rounded long edge because his method is to use the tool tipped up on the edge instead of held flat on the tool rest.
It worked like a charm for me on some finicky end grain.

 

[hockenbery]

Ya know Al, you made a reference to Stirt a few weeks back. I checked him out, bought his video, and then bought his "Scrapers", which he uses like no one else I've seen. I am sure you already know this, but he even sells them with a rounded long edge because his method is to use the tool tipped up on the edge instead of held flat on the tool rest.
It worked like a charm for me on some finicky end grain.

It's a nice tool when you need it.
John Jordan uses a similar scraper but he has two or one with double ends so he can scrap in each direction on a hollow form. Al does bowls and platters so just needs the one angle.

 

[robo hippy]

Well, cutting technique is one thing, grain orientation is another and different tools 'presentations' work better or worse. A scraping cut, with the edge at 90 degrees to the spin of the wood, is one cut, and a shear cut, with the edge at an angle to the rotation of the wood is another. The shear cut can be done with the bevel rubbing or not. If it isn't rubbing, then it is called a 'shear scrape' but isn't a scraping cut at all. Which cuts more cleanly? If you are cutting end grain (spindles or hollow forms) a scraper can to as good of a job as a gouge for hollowing purposes. For cutting spindles, I use a bevel rubbing cut most of the time, and some times I even pick up a skew. On bowls, you can't beat a scraper for heavy stock removal, but it doesn't leave a very nice surface. Most will use a gouge with a high shear angle bevel rubbing cut for a final pass. I always clean that up with a shear scrape, which again is at a very high shear angle, but not rubbing the bevel. This is better for removing small ripples that you could remove with 80 grit. Difficult to shear scrape the inside of a bowl with a gouge, so I use a ) nose shaped scraper. I prefer a shear scraped surface for sanding on bowls because no matter how delicate you are with the bevel rub, there is some burnishing. Also, rubbing the bevel generates a tiny bit of 'bounce/oval shape' in the bowl. Not critical unless you are going for less than 1/8 inch thick. You can get a piece as close to perfectly round by shear scraping as humanly possible, a very slight step up from how round you can get them with gouges: think 1/16 inch out of round, which translates to 1/32 plus/minus, which is very close. Scrapers work okay for sweeping across the bottom of bowls since you are not cutting down through the grain, but across it. Never use a scraper/scraping cut any where near the rim of a hollowed out bowl as "my bowl made this funny screeching and howling sound and then it blew up" vibrations will occur. Scrapers will generally cut more cleanly in harder woods than in softer ones. I don't use carbide scrapers. They won't do anything that you can't do with standard scrapers, and you can resharpen standard scrapers thousands of times before you wear them out... I prefer scrapers for shear scraping to gouges. I am starting to think that a lightly burnished edge rather than the grinder burr works a bit better, not for durability, but for a slightly sharper edge. The higher the shear angle, the cleaner the cut...

A bunch of random thoughts, but a shear scraping video should be coming this year... or next...

robo hippy

 

[Bill Boehme]

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.

There are some carbide tools that are actually cutters ... the ones made by Hunter foe example. The flat topped ones are scrapers and start out pretty sharp, but not for long. They stay sharp enough to barely scrape by for a long time, but the results won't be as clean as you would get with a HSS scraper. The main difference is that the HSS scraper has a bur on the edge that is actually a cutting edge that can take really clean shavings when shear scraping. The flat topped carbide scrapers can't do that. When you're working with really hard wood is where carbide tools have a great advantage. Some of those hard woods will dull HSS almost instantly, but carbide will usually last long enough to make them worth considering for something like that even if it means wearing out a couple cutters on a single project.

I have some carbide tools that are useful for some tasks, but 99% of the time I use HSS tools.

 

[Raul McCai]

All I can tell you is that if you don't do it the way I do it then you aren't doing it my way.

 

[robo hippy]

Raul, that reminded me of a favorite scene from the Princess Bride, if you are a fan.... about 'do it your way'...

View: https://www.youtube.com/watch?v=EE2TZAdoaS8


robo hippy

 

[John Torchick]

Now if we can just agree on whether the Egyptians used cutting or scraping copper tools to build the pyramids.
I just giggle when I hear the explanation of copper tools being used to cut 200 ton granite stones.

I always thought it was space aliens.

 

[john lucas]

A lot of questions going on in this thread. Carbide scrapers are good to remove wood quickly with little or no skill. They don't leave a good finish and get dull fairly quickly so they leave an even worse finish. For roughing bowls they are pretty good but if you want a clean finish that requires little sanding then you need to go to HSS with a fresh burr, HSS shear scraping with a fresh burr, or Hunter style carbide cutters used as cutters instead of scraping. Here is my video on shear scraping.

View: https://www.youtube.com/watch?v=7oeiVQLeOd4&t=4s

Here is a video showing the Hunter Osprey. About 7 minutes in I show the diffference between scraping, cutting and shear scraping with that tool. You can see the difference even in a poor quality video.

View: https://www.youtube.com/watch?v=FnFdDo0jxGU&t=21s

 

[Mike Johnson]

I needed a cut off tool for my metal lathe and remembered they carried a thin one at Harbor Freight.
This comes with an assortment of small M2 High Speed Steel cutters for a mini metal lathe.
I drilled the proper sized hole in an aluminum handle and epoxied and pressed the cutters into the handles.
This package of cutters was $4.99 for the set so I ended up with cut off blade and (4) mini wood lathe tools.
These also come in handy for turning small brass and aluminum items on the wood lathe.

 

[john lucas]

Reed You will like this. I'm gonna order one.
https://www.etsy.com/listing/258527...FC2TFWqS9ZLtgHBZRd6s28QfhlW6nyvsaAs-REALw_wcB