[How do I?] Boring a hole through drill press spindle (for a drawbar.)

chunklemcdunkle

chunklemcdunkle

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I have an old craftsman floor model drill press that I've been modifying lately. It's pretty much your basic drill-to-mill conversion story. I'm not looking to plunge cut steel or anything. Just light stuff. Light passes.

As many of you know, the taper can't handle much in the way of side loads. It will disconnect and drop. So I'm trying to add a drawbar through the spindle where it would thread into the top of the shafts tang. I'm thinking a threaded rod (#8-32) will do just fine. But... I have to bore a hole for it first.

I just have no real way to drill this hole and stay centered all the way through the spindles 15" shaft. The obvious answer is to use a machine lathe. I mean really, if I find a wood lathe that has a through-hole spindle, then I could probably use it. The steel seems relatively soft enough.

I have zero lathes available to me.

I guess I'm just looking to pick y'all's brains. Any ideas? Is this a bad idea?
 
On your conversion, it sounds like you intend to hold any cutting tools in the drill chuck? Is that right?
 
My take was that this DP has a MT spindle. In drilling a hole through 15", chances of success are slim, even if you had a lathe.
 
I did about 18" once when I was making an R-8 spindle. I had to braze up a double extension drill to finish. I had access to a big-ol lathe that would fit the whole thing inside the spindle.

The best way is to start with a un-cut bar, drill, and then turn between centers .

You want VERY well-rounded drills, with equal cutting edges.

Sent from my SM-S911U using Tapatalk
 
Just admit it- you ain't set up for this
Save your ducats and buy a small milling machine. A small lathe too if possible.
 
chunklemcdunkle said:
I have an old craftsman floor model drill press that I've been modifying lately. It's pretty much your basic drill-to-mill conversion story. I'm not looking to plunge cut steel or anything. Just light stuff. Light passes.

As many of you know, the taper can't handle much in the way of side loads. It will disconnect and drop. So I'm trying to add a drawbar through the spindle where it would thread into the top of the shafts tang. I'm thinking a threaded rod (#8-32) will do just fine. But... I have to bore a hole for it first.

I just have no real way to drill this hole and stay centered all the way through the spindles 15" shaft. The obvious answer is to use a machine lathe. I mean really, if I find a wood lathe that has a through-hole spindle, then I could probably use it. The steel seems relatively soft enough.

I have zero lathes available to me.

I guess I'm just looking to pick y'all's brains. Any ideas? Is this a bad idea?
Click to expand...
Hello and welcome,

I've been down this path and understand what you're trying to accomplish. It was a while back but if I remember correctly I did something like what's being discussed here:


Ultimately it was unsatisfactory, as was the lathe milling attachment and the homemade mill/drill I built.

https://www.hobby-machinist.com/threads/homemade-vertical-mill-drill.77611/

All of these were learning experiences but in the end I spent more money and time trying to accomplish this than it was worth. And, I should have known better since I previously owned a Gorton MasterMill.

Best advice I can give is start looking for a RF30 or clone if you're on a budget. Mini mills can be had pretty cheap but the RF30 can do real work.

Once you start down this path machines will likely start coming available, ask around people you know, someone might just have one lurking in the corner of their shop.

If you do see something for sale close to you for a decent price post it up here and we can offer advice. You have found the right place to ask this question and we'll even help you do things we think are ill advised as long as you won't get hurt.

John
 
Also, If you don't already have a lathe I'd recommend starting with that as a first machine tool. Much can be accomplished on a lathe that a mill can do but not much the other way around.

John
 
I think my record is ~12" and it was a long slog even in the lathe. The right way to do it is gun drilling with high-pressure oil feed, which doesn't sound like it's in the cards. I'd probably be exploring alternate ideas.

GsT
 
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