# Steel For Horizontal Mill Arbor



## G-ManBart (Nov 22, 2022)

My K&T 2H came with a couple boxes of cutters and one pile turned out to be metric, which surprised me.  They are mostly 200 x 20 mm and have a 40mm arbor hole.  The machine didn't come with a 40mm arbor, but it did come with a couple of new, fairly large end mill holders including one for 1.5" end mills.  Since I've got a lathe I was thinking of making an arbor to take advantage of the metric cutters.  I then did a little research and found a video of Keith Rucker doing pretty much the same thing to use 1-1/16" cutters he had, so I figured my idea isn't crazy.

The plan would be to turn one end down to 1.5" for the end mill holder, leave a section larger than 40mm as a shoulder, turn a short section to 40mm/1.57ish and then turn the remainder down to 1-1/4 to use the spacers and running bushing from my 1-1/4" arbor, and thread the end for the nut from the same 1-1/4 arbor.  I think it's a pretty reasonable project I can pull off without too much trouble, but I'm not sure on steel choices.

I'm already making a special trip to the place I get this sort of stock from or I would probably just make it from some CRS I have on hand.  A couple of options that I've bought there before are A311/1144/Stressproof, 12L14, 8620 and O1 in the proper size (along with common CRS among many other options) and likely drops which aren't too expensive even at current prices.  I'm leaning towards the A311 since it's supposed to be resist deformation when machined and this will have varied thicknesses as well as at least a short keyway, but maybe I'm overthinking things?

Or would I simply be better off selling the metric cutters?  They appear new but some have spots of surface rust, dirt and grim that should come off easily.


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## benmychree (Nov 22, 2022)

I might use Stressproof  You could cut a long keyway without fear of it bowing.  I made one many years ago with  a #10  B&S taper, I made from an old truck axle, it was quite tough on the outside but softer on the inside, I cut a full length keyway, but it did not distort too much, and I was able to finish grind it at work.


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## MrWhoopee (Nov 22, 2022)

Stressproof


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## Ulma Doctor (Nov 22, 2022)

1144sp is great stuff, you won't go wrong there


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## G-ManBart (Nov 23, 2022)

Okay, sounds unanimous to go with A311/1144/Stressproof....figured that would be a good choice.  Now I'll cross my fingers they have some drops


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## Aaron_W (Nov 23, 2022)

benmychree said:


> I might use Stressproof  You could cut a long keyway without fear of it bowing.  I made one many years ago with  a #10  B&S taper, I made from an old truck axle, it was quite tough on the outside but softer on the inside, I cut a full length keyway, but it did not distort too much, and I was able to finish grind it at work.



Could he make a 40mm x 1.25" bushing to run these 40mm bore cutters? I think you've mentioned that as a possible option to run a cutter of wrong size arbor.


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## G-ManBart (Nov 23, 2022)

Aaron_W said:


> Could he make a 40mm x 1.25" bushing to run these 40mm bore cutters? I think you've mentioned that as a possible option to run a cutter of wrong size arbor.



I have seen people mention doing that, but I was thinking it would wind up being a pretty thin bushing (maybe not an issue).  

I have a 7/8" arbor as well, but need to make spacers and a running bushing for it.  That would let me make a bushing with a bit more meat to it.  I didn't think about that initially because I didn't have the correct arbor support for the 7/8 arbor, but one showed up from Lost Creek Machinery yesterday


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## Aaron_W (Nov 23, 2022)

G-ManBart said:


> I have seen people mention doing that, but I was thinking it would wind up being a pretty thin bushing (maybe not an issue).
> 
> I have a 7/8" arbor as well, but need to make spacers and a running bushing for it.  That would let me make a bushing with a bit more meat to it.  I didn't think about that initially because I didn't have the correct arbor support for the 7/8 arbor, but one showed up from Lost Creek Machinery yesterday



I was just thinking if you just have a few then making an arbor for them is a lot of trouble, and a bushing might serve the same purpose with less work. 40mm is 1.57" so yeah not a lot to work with.

John uses a horizontal mill, and I thought I remembered him mentioning a bushing as a possible option for using the occasional odd ball sized cutter that comes along. It could be all in my head though.


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## G-ManBart (Nov 23, 2022)

Aaron_W said:


> I was just thinking if you just have a few then making an arbor for them is a lot of trouble, and a bushing might serve the same purpose with less work. 40mm is 1.57" so yeah not a lot to work with.
> 
> John uses a horizontal mill, and I thought I remembered him mentioning a bushing as a possible option for using the occasional odd ball sized cutter that comes along. It could be all in my head though.



It's definitely not a bad idea at all.  I counted and I have ten of the metric cutters...all roughly 8" diameter, and a couple of different widths.  I suspect ten will last me a long time.

My thought was to make a "sorta" 1.5" arbor with a short section for the 1.575 cutters since I wound up with a set of 1.5" spacers and two running bushings in one of the boxes.  Then if I run through the cutters I can just turn down the 1.575 section to 1.5" and it'll be set for a readily available size.

The steel place had A311/1144/Stressproof in 1.75" so I bought a 20" length and it'll make for a good lathe project!


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