Odd mill/drill heirloom

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Batmanacw

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My great uncle, who lived to 103, cobbled this machine together long ago. He was a machinist around the turn of the century. I'm not sure how old the machine is or the origin. It does have metric bearings and one aluminum pulley in the home made part. This thing is all cast iron and so solid as to be ridiculous.

20240408_112542.jpg

It had a home made xy table and vise to be used as a mill. It's definitely heavy enough to pull it off. Lol.

The pulleys were very cobbled together. He basically made his own step pulleys but not particularly well.

I intend to use this machine as a fairly heavy drill press. How slow is slow enough to run big drill bits in steel. Let's say up to 1.5" or 2"?

If I do what I'm considering right now I'll get down to 144 rpm but only up to 935 top speed. The pulley reduction will be pretty insane. I'm thinking that will be right in line with larger drills, running annular cutters, and possibly the occasional boring head.

This only has a 1/2 hp single phase motor but I'm considering a 1 hp 3 phase on a vfd eventually.
 
1.5" and 2" you are likely to get in trouble with the spline's strength even if you can get slow enough.

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Weldingrod1 said:
1.5" and 2" you are likely to get in trouble with the spline's strength even if you can get slow enough.

Sent from my SM-S911U using Tapatalk
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I've drilled 1.5" with a Taiwanese mill drill. This one is considerably more beefy.
 
I would be surprised if a mill/drill that light could drill holes 1.5" to 2.0" in diameter. I have a Jet 125VS 3 drill press that has a 3 phase, 2 hp, 2 speed motor. It's only rated for holes up to 1.25" in steel and 1.5" holes in cast iron. The spindle is a MT 3 spindle taper and has speeds from 150 rpm to 2,000 rpm. The machine weighs in at 740 lbs.
 
projectnut said:
I would be surprised if a mill/drill that light could drill holes 1.5" to 2.0" in diameter. I have a Jet 125VS 3 drill press that has a 3 phase, 2 hp, 2 speed motor. It's only rated for holes up to 1.25" in steel and 1.5" holes in cast iron. The spindle is a MT 3 spindle taper and has speeds from 150 rpm to 2,000 rpm. The machine weighs in at 740 lbs.
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That machine weighs a lot more than it looks. I'd guess 600 lbs. The table is 1" thick cast iron. The column is thick cast iron.

I'd like to focus on rpm choices rather than hypothetical drill sizes if at all possible. I just picked a couple bigger sizes so you guys would understand "big". Some folks think big is 3/4". Now it's all anyone can think about, missing the bigger question.


I've drilled a 1.5" hole in mild steel with my Taiwanese mill/drill. That is a baby compared to the new machine.
 
It may be big and heavy, but I doubt 1/2 hp is going to provide enough torque to drill even a 1" hole. The Jet has 2 hp and a low speed of 150 rpm and is still only rated for a 1 1/4" hole in steel.
 
projectnut said:
It may be big and heavy, but I doubt 1/2 hp is going to provide enough torque to drill even a 1" hole. The Jet has 2 hp and a low speed of 150 rpm and is still only rated for a 1 1/4" hole in steel.
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Are you aware of the actual question I asked about rpm? You kind of answered it without realizing it. Next time I'll leave our the hypothetical drill sizes and see if the focus is instead on the question.
 
Personally, I think the 144 RPM speed you've said will be your lowest speed is too fast for drills this size. I have drilled 1.5" holes with my BP mill and run at 60 RPM which seems to be about right. This is also the approximate speed I use when drilling a hole that large in my lathe.
Just my two cents.
Ted
 
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