I made a new scraper chisel for my lathe duplicator the other day. The old one was 1/8″ thick and I replaced it with one that was 3/16″ thick to help reduce chatter. I had at first air hardened the thicker one. But, I noticed that the point of my Buck knife would scratch the steel. In using it, it would get dull pretty quick.
So, last night I reheated it and quinched it in thin oil. My Buck knife point wouldn’t faze it this time. And, after a dozen knobs, it was still cutting fine.
Some time ago I made some small plane blades from A2 and had also quenched them in thin oil. Those also were very hard. Later, I made a hand chisel that same way, but discovered that it was to brittle for the poundings it took.
So, my observations are that oil quinching A2 produces a very hard, but more brittle tool. That is ok for something like a lathe chisel but not so ok for a hand chisel.
My ‘thin oil’ was half 30# motor oil and half paint thinner.
I almost bought a Sorby spindle gouge the other day, but said to myself, “Ah, I can make that”. Will be fun trying.
My cousin gave me a piece of 1/2″ round HSS steel here while back and It made a great Schoogie chisel. Amazing what those will do.
PlaneWood by Mike_in_Katy
PlaneWood
Replies
Mike, your oil hardned only tool may also break under shock. You may want to temper it back to a light straw color to help prevent it from shattering under load. I have made lath tools out of truck leaf springs, mower blades and files. Proper tempering is the secret.
Well, my first one (the thin one) made over 1500 knobs. Is this one shatters, I'll just make another!
PlaneWood by Mike_in_KatyPlaneWood
Mike,
A's are air hardening steels and shouldn't be drenched. Pretty much the same process, except air instead of oil. Heat it red hot for however long necessary. Let it cool. Reheat to temper tempature and then just let it slowly cool. Be careful not to let it cool on something that will act as a heat sink. Will screw the temper up.
O's are for oil, and W's for water.
Don
Don, I'm aware of what they say. But, I have been getting my A2 harder by doing the oil quinch. I don't temper, either. I heat it up to dull yellow and keep it there for about 1 minute then drop it in the bucket of light oil. When cool, I sharpen it and use it. Doing it this way, I can get about 15 knobs per sharpening. When I air cool it, maybe 5 or 6. (cocobolo is mostly what I'm turning)
PlaneWood by Mike_in_KatyPlaneWood
PlaneWood
My tool steel book does mention oil quenching A2 as an alternate method, however, do yourself a favor and buy some quenching oil. The mixture you are using could flash up and burn you quite badly without warning. Quenching oil will not do that and is not that expensive. As for air hardening try bringing it up to red hot and then cooling it with a blast from an air hose. Remember still air is an insulator. You need to keep the air moving same as you would keep the tool moving when oil quenching, use figure eight motion when oil quenching. Try this with the air and see if it will be hard enough for you without being brittle. Air hardening and tempering should produce a tool with about 56c - 58c. Without the tempering it should be 58c - 60c. Don't hold me to those numbers, I'm going from memory. If you want a harder edge maybe you should be looking at a water hardening steel. I don't have my book here right now but would gladly look some info up for you or just go to any good tool and die shop and start asking questions. They may even have an old book they will give you.
RichThe Professional Termite
On a similar note, where would I find a book on metal working. I'd like to learn about tempering metals and working with different types of steel. I guess metalurgy would be the word I'm looking for. If any of you could recomend a good book or a source for a good book, that would be great. Thanks.
Doc,
Look for the old reliable Machinests handbook. Great book.
Don
Thanks Trialnut -
Will try the air hose bit next time. I'm not after perfection. I'm after what works and speed. 15-20 knobs per sharpening is ok for me (better than 5 or 6). Now if I were to be able to get it to 50.........
I'm not after perfection on sharpening either. 4 or 5 passes on my belt sander (320 grit) and I'm done. It's a scraper, so gotta keep the burr.
Oh yeah, I do the quinching outside on concrete in a 5 gallon bucket with a lid nearby.
PlaneWood by Mike_in_KatyPlaneWood
Mike,
For 50 try this:
https://www.jlindustrial.com/search/result.asp
If the link doesn't work, it's J&L Industrial Supply. Search the site for Carbide blanks. About 200 different sizes are offered, and mostly in 6 or 12 inch lengths. Inexpensive too considering. Or, have you tried the "T" steels?
Don
Edited 11/16/2002 12:00:32 PM ET by Don C.
Don -
Can you get 'green' grinding belts anywhere?? Hmmm, I have seen diamond belts. Will have to check that out. They did have 1/8 x 1/2 x 3" carbide blanks. Didn't see any that were 3/16" thick.
PlaneWood by Mike_in_KatyPlaneWood
Mike,
Fortuitous (sp) timing. Just sat down to dinner. Try this:
https://www.jlindustrial.com/Search/item.asp?IK=STB%2D32220
There are many others, and J&L will get you what you want if you call. Green Belts? Have to look at that abrasives place out of Gettysburg. They have darn near everything else except the boss spindle tubes.
Don
Another:
https://www.jlindustrial.com/Search/item.asp?IK=STB%2D32200
or-- 3/16 x 1/2 x 3 is here:
https://www.jlindustrial.com/Search/item.asp?IK=STB%2D32120
Well, looks like J&L may have the norton belts also.--$50 each! haha
Edited 11/16/2002 5:16:11 PM ET by Don C.
Edited 11/16/2002 5:21:22 PM ET by Don C.
Edited 11/16/2002 5:23:45 PM ET by Don C.
http://www.mscdirect.com is also a source for carbide blanks.
Yep, J&L and MSC have both been in the mail order business for a long long time. Both have excellent reputations also. Does MSC still carry woodworking materials and supplies? Haven't seen one of their catalogs for quite some time now and they use to.
Don
MSC has a lot of hand held power tools, including routers and biscuit joiners, but no stationary woodworking power tools, except belt and disc sanders. They have some hand tools, a few cheap brands of chisels, no hand planes, and some cabinet hardware. Last I heard, they'll still send a free catalog to anyone who requests one.
Uncle Dunc,
That's a good idea about the catalog. They do carry a lot of things that can come in handy. Last time I saw the catalog they did carry table saws, jointers, planers, etc. Mostly in support of the pattern and mold making business. I suppose with cad, edm's, 3d model molding and all the other 21st century stuff, the old hand work method is somewhat dated. Thanks,
Don
Planewood,
If you're after down and dirty, you might want to try 4140 or 4640. Both these steels can be heated in a few seconds at the tip with an acetylene torch to cherry red, and if there is enough steel behind, need no quenching. Lost my spec sheet on 4640, but 4140 heated this way will harden up to Rock c 55-60. Quenching with air blast will get it harder. No tempering necessary, especially for your application. Tool steel suppliers usually carry it.
Clampman
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