Speed Reduction for Old Drill Press

[Gordon Gould]

EDIT: I couldn't figure out how to make the photos work but they are down in Post #7 all glumped together. Sorry.



I have been running this Craftsman Drill Press since I was 14 years old. At that time, 60 years ago, it belonged to a man down the road who built metal tables with ceramic tile tops as a side business. I worked for him part time. 8 years later he became my FIL and I finally ended up with the drill in my shop.

View attachment 651259

I often wished that it would turn slower than 560 RPM. Wanting an indoor project recently, I decided to slow down the drill - finally. A factor of 3 seemed about right for what I do. So I ordered a set of pulleys and a 1/2" shaft 12" long from McMasterCarr. The pulleys were 1-1/2" and 4-1/4" pitch to give a 2.83 speed reduction ratio and a 200 RPM low speed and 1900 top speed. I also ordered 2 flange bearings and an A21 drive belt from Surplus Center.

First I made a 6-1/4" X 12" motor mount pad with ears on it so it would fit snugly over and be supported by the drill press mounting pad built into the casting. Then remounted the motor so I could continue using the drill.

View attachment 651260

View attachment 651262

View attachment 651263

Next I welded up the C-Frame for the spindle from 4 X 1/4 bar. I pre-drilled the end plates for the bearings and managed to keep it square during welding. This is the first of 2 passes.

View attachment 651264

I added slotted holes to adjust the pulley tension and assembled the bearings and shaft.

View attachment 651265

View attachment 651266

Then mounted the new spindle to the motor mount pad putting the speed reduction pulley on the bottom and the original 4 way drill pulley on top. I had to cut a notch out of the side of the drill casting for the main belt.

View attachment 651267

View attachment 651268

While I was at it I mounted a switch box to another ear on the motor mount pad so I could attach a grounded power cord. Another thing I have been thinking I should do for a long long time.

View attachment 651269

Turned out to be an interesting project and works as it should. Drilling 1" plus holes will no longer be the adventure it once was. Don't know why I waited so long.

gg

 

[Reb954]

Interesting story but it would be better if your attachments would open.

 

[Gordon Gould]

Interesting story but it would be better if your attachments would open.

I agree. This new picture thing is weird. They open for me OK. I don't know why they show up as attachment numbers rather than inserted pics. The old way was so easy. I hope it gets fixed.

gg

 

[Ford850]

Interesting story but it would be better if your attachments would open.

It IS a good story, especially the part when he married the boss's daughter so he could get this drill press.

 

[Reb954]

Gordon, I even checked this on my phone and they don't show up on it either. Not sure why.

Ford, I see your point but that could also make for a very expensive drill press. Likely it was worth the price but...???.

 

[downsizingnow48]

I get invalid attachment messages on both laptop and iphone.

 

[Gordon Gould]

Well here are the photos maybe. Can't tell if they are there or not.

EDIT: I guess they are there. Scrambled up but should be easy to figure out.

gg

 

[Reb954]

Clever idea and well executed.

And if you ever wanted to take it back up to the original rpm you can just add more step pulleys to the motor and jack shaft.

 

[oldnslo]

Nice job on adding spindles

I just installed a 1150 RPM vs the 1750 RPM motor on my old drill press. Be nice if it went a little slower but this was well within my capabilities

 

[pmsmechanic]

I've never explored the idea but I've often wondered if a small planetary gear set out of a compact automatic transmission wouldn't work. Install it on the quill and you wouldn't have to run the belts as tight to turn a large drill bit.

I like what you did with yours.