Which steel should I use ?

[Wino1442]

Hi all....I picked up an Atlas mill (MF) a couple of months ago. It's been stripped down, cleaned, and put back together, but I have to make a new arbor for it as the one that came with it is bent. So, my question is what type of steel should I use for the arbor? The arbor that came with it is 3/4"...would I be better off making the new one 1" ? Also, would anyone know if the notched piece that engages the drive is an integral part of the arbor or is it pressed on?

Thanks

 

[Suzuki4evr]

Don't know about the other stuff, but 4140 is always a good bet for an Arbor in my book.

 

[Bob Korves]

It is quite possible to straighten an arbor if it is not bent too badly. Just requires a press, a couple blocks, a dial indicator, and careful patience and thought. Keep track of the indicator readings at the bottom of each push, to help plan the next push. Distance between supports also matters. Flame can also be used to advantage, if you know how. I have little experience with heat straightening. Trying to straighten it is often worth a try, you can consider it already broken at the start, and then you can learn something...

We straightened the table lead screw off a round ram Bridgeport mill that got loose on a metal trailer deck and banged the handle into the rail of the trailer. It was visibly bent at the handle end, and showed bending all along the length of the screw, but we got it to within .002" along the entire length of the screw. It took about an hour and a half to do that job, learning as we proceeded.

 

[Chipper5783]

The actual grade of steel is not critical. If you have a piece of mystery metal that is magnetic, cuts well, finishes well - then use that. As Suzuki4evr says - 4140 is a great choice. What size? Well, that depends on what size cutters you have, or plan to use. The benefit of a smaller arbor is that you can sleeve larger cutters and use them on the smaller arbor (perhaps not ideal, but it does work). If your existing bent arbor has a set of sleeves - stick with that size and you can reuse the sleeves.

The notched section that engages the drive is integral on my arbors. How you choose to make it is up to you (a built up arbor could be made to work).

Let us know how you make out. David

 

[francist]

Here is a link to one I made for my MF a few months ago using a separate piece for the drive collar. It has been working just fine for me. And if I recall I just used 1018 that I had on hand.

Horizontal Milling Arbor

It works for me, I don't know about you. But worth looking into. Hmmm, interesting. I did think of using a milling cutter holder (aka end mill holder) as a source of the MT2 end and turning off the "holder" portion. The arbor part could then be attached to that. In part I steered clear of...

www.hobby-machinist.com

frank

 

[benmychree]

For material 4140 HEAT TREATED is the best choice. So far as size is concerned, 3/4 is NOT a standard arbor size, the standard sizes are 7/8, 1", and
1 1/4". I'd go with 7/8 for such a small machine, and make a shouldered, keyed bushing to use with larger size cutters.

 

[cjtoombs]

The above recommendations are all good. I would add that 1" tools are easier to find than 7/8", but given that you probably already have the tooling for the 7/8, that would be my first choice. If you wind up making an arbor instead of straightening it, it will be easy enough for you to make a 1" as well. Those sleeves are not cheap, by the way.

 

[benmychree]

What size/taper is the spindle?

 

[cjtoombs]

They are MT2 with a flange that has slots for driving lugs on a driver that threads onto the spindle nose. I believe that the flange is 1.5" diameter.

 

[Wino1442]

Thanks for the responses.....I'm going to make a new arbor rather than try to straighten it because the tapped end has quite a few longitudinal cracks (see photo). Also, as [U]benmychree[/U] pointed out the correct size of the arbor that came with my mill is 7/8". It also did not come with any cutters or spacers and from what I've read 1" seems to be a more common size. And thanks to [U]francist....[/U] his post about his arbor will help me a lot. Thanks again