Reducing diameter of a shaft

J

jbayless

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Hi everyone,

So I'd like to replace the stand for my drill press with one that is taller. I thought it would be a simple matter of buying a longer metal rod, but I seem to have hit a hiccup. Currently, the drill stands on a 32.5 mm diameter steel tube with a fine-ground finish. It fits exactly into the base and the head of the drill press, which have the same diameter, but it's only 30 cm (12") long. I would like to replace it with something twice as long (600 mm or 24"), but 32.5 mm (1.28") diameter doesn't seem to be a a standard size of anything.

I can buy a 1.375" or 35 mm mild steel shaft quite easily anywhere, but I don't have a centerless grinding machine which is what I imagine would be the best tool to use to reduce the diameter. Does anyone have any tips for reducing the diameter of a fairly large and heavy steel shaft?

Thanks,

Jacob
 
Grinding is usually the preferred method of controlling size, finish, and straightness, but with care, a lathe can do an adequate job of making a replacement part for your drill press.
 
Emphasis on the word "CARE".

"Billy G" :whistle:
 
One possibility is to investigate the availability of replacement parts for the floor model equivalent of your drill press. It's possible that you could purchase a mast for it and simply swap them out.
 
I agree with Froneck. I'd sell off the bench machine and buy a real floor model drill press. There are plenty on CL.

Randy
 
I didn't consider the size and function of the piece in question, but I would concur. I was focused strictly on the question. That diameter is likely engineered to be the minimum acceptable under the loads seen for a small bench drill press. If you increase the load, which lengthening it would, it will not be rigid enough. I agree with the trade up scheme. You should be able to get a decent floor drill press easily enough.
 
Jacob,
Are you trying to gain a bit more working room for your projects?
Not sure how your mast connects to the base of your drill, but......I found the height of my pedestal drill to be at an awkward height for me so I made a spacer that fits between the base plate and the mast socket to boost it up. It is just some 16mm (5/8") plate circles welded to either end of a thick walled pipe that I had laying around. I welded the flat bar in for stiffeners. Obviously it is a bit overboard for what you want but maybe on a smaller scale?
This has also gained me an extra foot of working room, although I have never used it yet.

IMG_5297.jpg

IMG_5296.jpg IMG_5295.jpg

Cheers Phil
 
Thanks for the advice everyone!

Yes, a little bit more room. The main reason is that the cross-slide vise that sits on the base takes up almost all of the working height, even with nothing clamped in it, so there often isn't room for the drill bit to fit in. The mast basically has a mating socket in the base that it fits into, where it's retained by a set screw. It doesn't have a flange like yours does. I suppose I could try expanding the hole instead of shrinking the shaft, although I don't know how I'll do that... boring might work, but I don't have a machine that can do that yet.

Unfortunately I've never been trained in how to weld =( so I don't know that I could try an approach similar to yours without it being quite complicated.

I'll save up for a real drill press, but until then I just have to work with what I can afford.
 
Jim,
Can you post up a pic of your drill press for us to have a look at. Might get some more suggestions if people can see what you are talking about. Lots of different minds here that approach things differently.

Cheers Phil
 
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