Drill Press Mod

[BSeyler]

I bought this Delta 16” 12 speed floor model drill press in about 1987. Top speed is 3000 RPMs and lowest speed of 250 RPMs. 250 works great when drilling holes 1/2” or less in metal, but it’s too fast for larger holes. Bits tend to grab and end up chipped. I found this reduction kit that cuts speed by 75%. Now, I have 750 RPMs top speed and 62.5 RPMs low speed. I dressed up a 1” bit yesterday and did a test run in some 1/4” steel. First drilled a 1/4” pilot hole and followed with the 1”. It took some effort to get the bit in shape, but once I did, both flutes were cutting uniformly. This is one of the best mods I have done in a while. Now, I need to fab up a guard to cover the new part.

 

[EDankievitch]

Very cool idea. I’ve got a very old Craftsman drill press that needed a motor. Found a motor but was wrong rotation. After some digging we were able to switch the wiring and change the rotation. It’s a lot larger motor than needed. But there is no substitute for power. Not sure the Rpm but slower would be nice sometimes. I like your Idea.

 

[BSeyler]

I still have a little fine tuning to do to get everything on the correct plane. A little more of the original guard needs to come off so I can lower the pulleys a bit.

Seems like the old stuff is often in a class of its own.

 

[seafish]

Nice work and GREAT idea.

It looks like you bolted on another mounting plate for a third spindle assembly and then used a longer belt.

Did you fabricate the mounting plate and spindle assembly??
Or were you able to use "off the shelf" parts??

I have the same press and would love to do the same...would it be be possible for you to post up links to specific items that you used for this conversion??

TIA

 

[BSeyler]

I was going to build something until I found this kit at: https://www.roguefab.com/product-category/drill-press-reduction-kits/
It cost $150. I'm sure I could have done it myself cheaper, but this eliminated the trial and error factor and got me running in short order. I am impressed with the quality of the kit. I used the new belt that came with the kit to go from the motor to the large pulley. I had to buy a 30" belt to go from there to the center pulley. Instructions stated that belts may not fit and may have to be replaced.

I spent some time getting all of my larger bits back into shape. Most of them were chipped and I dreaded using them because it seemed I had to sharpen them often. My ag teacher in high school made us sharpen large bits as part of our course. We had an old industrial drill press that turned about 25 RPMs. If curls were not coming out equally, he sent us back to the grinder. Now, I'm glad I learned that skill and have sharpened hundreds of bits over the last almost 50 years. I drilled a 1" hole in 1/4" steel and the bit looks just as good afterward. Before, I would have had to dress it a time or two before being finished. Speed kills large bits.

 

[Wayne M.]

Hmmmm. I think I have the same drill press but a 2000’s model. Same complaint that it don’t slow down enough. Thanks for the heads up.

 

[seafish]

Well that sure makes this an easy modification...THANKS for the link to the kit!!!

 

[HPSimpson]

That's a super idea, slow the big drill bits down, and maybe I won't be on the grinder shaping the drill bits, thanks!

 

[SRay]

I have a 100 year old drill press. Massive 750 lb piece of machinery.

Came from the time of overhead shaft and flat belt drives.

My dad installed a 3 speed manual car transmission on the main shaft. (Now comes standard with reverse!)

I’m not sure what year the 1 hp motor is but it’s larger than a 10 hp of today.

As stated above, very slow speeds is what the large drill bits like.

We have drill bits up to 2 inches for this press. (No longer have this bit, snapped)

 

[bighammer]

I bought a Jet 17" drill press about 25 years ago. I never liked changing the belts and often found myself being lazy about it; sort of the "I know it's way too fast/slow, but I'm only drilling one hole" mentality.

I took an old 3 phase motor, made a mount for it and wired it up with a cheapo VFD I had sitting around the shop. Now the belt can stay in one place and I have variable speed from 0 to 3 or 4000 with just push of buttons. Very handy modification.