- Joined
- Jan 8, 2013
- Messages
- 232
I have a Delta DP-220 drill press made in 1951 which is in great original condition, but which ran (with the original two pulley/one belt set-up) at speeds intended for drilling wood (728, 1295, 2457, and 4507 rpm according to my cheap laser tachometer).
I made my speed reduction pulley to work like the ones that Delta offered as an accessory when the drill press was made. The "cap" piece (which I made from a scrap piece--explaining the several unnecessary holes in it) fits over the top of the column and can rotate to loosen/tighten the front belt. It is locked with three brass tipped thumb screws. The rear belt is loosened/tightened by moving the motor mounting plate (two bolts). The large "plug" (a 3" long chunk of steel) fits inside the column to keep the pulley mount straight. The pulley shaft is 1/2" drill rod and the pulley came from Electric Motor Warehouse on line. I pressed two roller bearings from MSC into the pulley and have a roller thrust bearing under it.
It now has 12 possible belt configurations but the two highest are too fast to use. There is some overlapping of speeds with the different combinations. For simplicity of belt changes, I will probably only use four of the possible speeds: 270 (the new lowest speed), 515, 960, and 3285.
I made this so I would have the lower speeds and I've already found that my drills work way better in metal now. This modification is obviously applicable to any two pulley drill press and was well within my capabilities as a relatively novice hobby machinist, so I highly recommend it to anyone with a too-fast drill press.
Bill Burton
I made my speed reduction pulley to work like the ones that Delta offered as an accessory when the drill press was made. The "cap" piece (which I made from a scrap piece--explaining the several unnecessary holes in it) fits over the top of the column and can rotate to loosen/tighten the front belt. It is locked with three brass tipped thumb screws. The rear belt is loosened/tightened by moving the motor mounting plate (two bolts). The large "plug" (a 3" long chunk of steel) fits inside the column to keep the pulley mount straight. The pulley shaft is 1/2" drill rod and the pulley came from Electric Motor Warehouse on line. I pressed two roller bearings from MSC into the pulley and have a roller thrust bearing under it.
It now has 12 possible belt configurations but the two highest are too fast to use. There is some overlapping of speeds with the different combinations. For simplicity of belt changes, I will probably only use four of the possible speeds: 270 (the new lowest speed), 515, 960, and 3285.
I made this so I would have the lower speeds and I've already found that my drills work way better in metal now. This modification is obviously applicable to any two pulley drill press and was well within my capabilities as a relatively novice hobby machinist, so I highly recommend it to anyone with a too-fast drill press.
Bill Burton
