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Aloris tool holders, are they case hardened or through hardened?

laminar-flow

Stainless
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Jan 26, 2003
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Pacific Northwest
I am trying to drill an Aloris tool holder and it appears to be quite hard. Does anyone know if these holders are just case hardened or what? What kind of steel would help too. I'll probably anneal it a bit just so I can drill it.
 
I am trying to drill an Aloris tool holder and it appears to be quite hard. Does anyone know if these holders are just case hardened or what? What kind of steel would help too. I'll probably anneal it a bit just so I can drill it.

Annealing is an all or nothing process, so no "anneal it a bit" is possible. Perhaps you are thinking of drawing the temper, which is a time and temperature controlled process that allows the hardness of steel to be lowered "a bit" or more. There is a risk of damaging your holder.

You can try a carbide die drill before risking ruining the OEM heat treatment.

There is also a process used by gunsmiths for drilling and tapping hardened parts called "spot annealing." That process is actually a misnamed localized drawing of the temper with an oxy-acetylene torch. It requires skill and experience.

Larry
 
I am trying to drill an Aloris tool holder and it appears to be quite hard. Does anyone know if these holders are just case hardened or what?

How far did you get with the drill? You would know pretty quickly if they are case hardened by going about .06" past the surface. Can you scratch it with a file?
 
Didn't get far at all, until I tempered it to 300C. Then it would cut through the case and I managed to drill it through. The inside is nice and soft. But I needed to counterbore the hole for a SHCS and it was a bit too hard for an end mill to CB it so back in the furnace to maybe 320C. That is where it is now. So Aloris holders, at least this one, is definitely case hardened.
 
I used an old AXA-8 tool holder, drilled and CB'd it for 4 10-32 SHCS to mount the ECI three hole gang tool holder to mount some ER-11 holders in some eccentric bushings for height adjusting. This is to make small parts in my Haas HPCL lathe.
 

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For others facing the same issue, years ago I did hardness tests on Aloris and clone holders. Don't recall the exact figures, but Aloris were about 10 points harder Rc and appeared to be a deep hard case. Easiest holders to modify were the Chinese (not the one Japanese I tested) imports. These are cheap and have accurately enough machined dovetails to be a good choice for modifications.
 
good you solver the problem, nice job.

I had spot annealed some hard, not too thick parts with a hard wheel and a die grinder. You grind/bring it up to cherry a few times. Sometimes you can just drill through with a point-mounted wheel. Tapping is tricky because you don't know if it annealed enough for the thread
 
We made some Tripan holders a while back. Used mild steel and color case hardened them. Worked great, then drew them a bit. Really pretty.
 

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Given the extra labor and time in small batch what is the advantage to case over using 4140 and a more simple though hard process on parts like this?
Yes I know why on axles or other drivetrain parts but on holders?
Of course in big volume the steel is much cheaper and you just dump them by the wheelbarrow full into the gas carbs.
I have never seen a cased insert toolholder called out by any major brand. A handful of steels and a wide range of hard but never case.
I am confused and admit to not very smart so talk to me on the why and there is no need to be nice.
Most of you here are real world. In school long ago this got passed over quickly.
Bob
 
I don't think the conversation is about insert tool holders, but the interchangeable tool holders that fit the tool post.

Back in NC days, shop had a HES lathe with DA Alorus and a foot valve hydraulic wedge. Those holders had a deep case. They survived a serious beating over decades and we're little worse for the wear.
 
i suspect most holders will be 1045 or similar and threfore not through-hardened.
 
I guess the advantage is the material is cheap, there is less distortion of the part when case hardening, and the surface can be really hard. If the entire part was left that hard, one could over tighten the tool post and crack the holder.

I used Heat Treating Bone Charcoal. I have a container about 6 x 5 x 5 made of stainless with a loose floating lid that drops down to the level of the parts and charcoal. A layer charcoal about .5" is on the bottom, parts are placed in and more charcoal is poured in, then a final layer on top, then the floating lid. There is a screw socket welded to the end so when the furnace is opened up, a 12" steel rod with a wood handle can be screwed on to lift it out. Up to temp and soaked for an hour or so. A 5 gallon plastic bucket of water with some sheet metal on the bottom is readied by bubbling air in it for an hour or so. Get ready to splash some water, I did it outside. Welding gloves on, open the furnace, screw in the handle, bring the container to the bucket, leave the lid on, and dump everything into the water. After cool, temper to keep the surface from being too hard. I'm not sure if tempering is needed so this could use some more study. Save the old spent charcoal to make up room if you only need to do a bottom layer of parts. Only new charcoal is needed just around the parts, or you can mix old and new to reduce the coloring (never done it but heard about the mixing).

If anyone has some additional info I'd be glad to hear it as I have not done much of this.
 
I guess the advantage is the material is cheap, there is less distortion of the part when case hardening, and the surface can be really hard. If the entire part was left that hard, one could over tighten the tool post and crack the holder.

I used Heat Treating Bone Charcoal. I have a container about 6 x 5 x 5 made of stainless with a loose floating lid that drops down to the level of the parts and charcoal. A layer charcoal about .5" is on the bottom, parts are placed in and more charcoal is poured in, then a final layer on top, then the floating lid. There is a screw socket welded to the end so when the furnace is opened up, a 12" steel rod with a wood handle can be screwed on to lift it out. Up to temp and soaked for an hour or so. A 5 gallon plastic bucket of water with some sheet metal on the bottom is readied by bubbling air in it for an hour or so. Get ready to splash some water, I did it outside. Welding gloves on, open the furnace, screw in the handle, bring the container to the bucket, leave the lid on, and dump everything into the water. After cool, temper to keep the surface from being too hard. I'm not sure if tempering is needed so this could use some more study. Save the old spent charcoal to make up room if you only need to do a bottom layer of parts. Only new charcoal is needed just around the parts, or you can mix old and new to reduce the coloring (never done it but heard about the mixing).

If anyone has some additional info I'd be glad to hear it as I have not done much of this.

Time from start of process to end at $60 per hour. Assume soak time unattended and free.
Bob
 








 
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