Delta Homecraft Drill Press Slow Speed Pulley Mount Machining

Last year I picked up a Delta Homecraft 11" drill press, probably from the late 1940's and its becoming one of my favorite tools...
The spindle runs the straightest of any drill press I've ever used - only a few thousandths run out on the dial indicator. The quill lock is fantastic too as are the interchangeable spindles (note the spindle with set screws and a 1/2" shank - safer for the side loads I put on it)

After inspiration by this thread, https://www.garagejournal.com/forum/showthread.php?t=312834&showall=1
I decided to come up with my own jackshaft mount for lower speeds.

Featuring
- Plunge milling (manually scoot part forward or rotate, reclamp, replunge)
- Homemade boring bar
- 3 year old helper for pressing in the bearings
- Dual bearings on jackshaft for moment support

I bought the pulley, aluminum, and belts, but pretty much everything else was "just laying around" or in the "junk pile" at work (bearings)

Not bad for a 34 year old engineer that sits at a desk most of the time, eh?

Did you calculate the reduction rpm's you're gonna get?

The work looks OK to me but I'm not a machinist, and don't own a mill.

I did have a similar Delta DP220 manufactured during the WW II Battle of the Bulge, according to the date cast-into the bottom of the table.

It basically cuts in half my previous low speed from maybe 500 rpm down to 250 rpm.
I measured this the old fashion way by turning the motor pulley and counting revolutions of the chuck.
This work is the best I've done on a drill press but obviously can't match a real mill for rigidity. During boring the spindle wiggled back and forth leading to the rough surface finish on the hole (I gradually increased hole diameter until it was right), but that just helps the press fit hole better, right?

Presuming you had a 1725 motor, the original minimum speed on the Delta Homecraft drill press was about 700 rpm per the manual. They are great little drill presses and quite heavy for their size. I ended up putting an 1140 rpm motor on mine to reduce the speed range down to about 460 rpm. But your triple pulley will go even lower. Nice work!

Sweet!

Nice!

Thanks for the link to the other solution that was good read as well.

Beautiful design, construction and machine work.

Those contemplating fabricating their own intermediate pulley should be aware this design is way more complicated than the Delta factory piece and has more parts than the minimum required to git 'er done, but will also probably function more smoothly and make changing belts easier than the minimum design.

jack vines

Damn good job for not having a mill to work with. You would be able to work wonders on a vertical mill with your creativity. Then you are going to need a lathe. The rabbit hole awaits you!

I love it! I have the same one. BTW, i need to take my chuck off, how do you do that? Sorry for steering your thread, just excited to see the same press as mine!

OccupantRJ said:

Damn good job for not having a mill to work with. You would be able to work wonders on a vertical mill with your creativity. Then you are going to need a lathe. The rabbit hole awaits you!

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Thanks.
To get the end mills (3/8" shank) in the 1/2" hole spindle, I had to make an adapter sleeve, which I made on this drill press, using it as a lathe: Insert drill into chuck upside down, lower into vise. Tighten vise, tighten vise to table (very careful to do this evenly). Release chuck, insert 1/2" shaft into chuck. Drill through shaft, just like a lathe. Zero discernible run out (insert drill rod through hole, roll across chunk of granite, look for wobble). I've done about 100 hours of mill/lathe work but 1000's of hours running a small aluminum fabrication outfit where we wished we had more than a drill press.

dougf said:

I love it! I have the same one. BTW, i need to take my chuck off, how do you do that? Sorry for steering your thread, just excited to see the same press as mine!

Click to expand...

This drill press model has interchangeable spindles. I had to buy the set screw one on ebay. Changing them out you just lower the spindle, loosen a set screw shaft collar, pull out the spindle, put in the other spindle, tighten the set screw (don't crash anything into the table).

Great work on the pulley mount. Found your thread from the Penncraft thread. I've yet you get a reduction on my 11" Homecraft. Yours is a great example. Thank you

What kind of vise are you using on the dp table to hold your workpiece?