macbruce Posted July 14, 2011 Share Posted July 14, 2011 I'm looking for an economical, simple way to slow this fine old drill down to say 150-300 rpm ( as you can see it's not getting any use now) If anyone has a DC motor or gear motor suitable to the task I'd be interested.......jack shafting is a possibility but not preferred, Ideas welcome....thanks mb Quote Link to comment Share on other sites More sharing options...
Backwoods Blacksmith Posted July 14, 2011 Share Posted July 14, 2011 You have to change the pully size. Either larger on the spindle or smaller on the moter. Finding a slower moter is possiable. If the current moter is 1725 RPM you might find a 900 RPM moter some where. Match the HP or go bigger. Make sure the frame size will match your bolt pattern. Made that mistake before. Adaptor plates can be made. Just extra work Good luck Quote Link to comment Share on other sites More sharing options...
monstermetal Posted July 14, 2011 Share Posted July 14, 2011 I have a really nice old "art deco" smaller industrial drill that I retrofitted with a DC motor and drive.. 3/4HP and a basic DC speed control with reverse... Worked really slick, especially for tapping small holes... Unfortunately I let someone else have the motor and speed control for another project so now I am on the hunt for a replacement myself.. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 14, 2011 Share Posted July 14, 2011 First check the motor speed if it's the faster of the common speeds then going to the slower 1725 will make a big difference. I don't think you can go to much of a smaller pulley on the motor side and going to larger pulleys on the drill side might be a problem too. Can you find a treadmill motor and use it with it's speed control? (common mod for old metal lathes to get a speed controlled motor). Quote Link to comment Share on other sites More sharing options...
arftist Posted July 14, 2011 Share Posted July 14, 2011 VFD is the hot ticket for these problems, DC motor is the tried and true old standy, 900 rpm motor is a great idea (if you can find one) rediculous expence new. If it were me, I would go with the jackshaft, been there done that. Quote Link to comment Share on other sites More sharing options...
poleframer Posted July 14, 2011 Share Posted July 14, 2011 Yep, I'd say jackshaft, make a larger mounting plate, put the step pulley that's on the motor on a jackshaft in the same position that it's in now, and mount the motor to the side and up a bit, with a small pulley on it to the largest step of the back pulley. Quote Link to comment Share on other sites More sharing options...
monstermetal Posted July 14, 2011 Share Posted July 14, 2011 If you guys had used my DC drive I don't think you would even consider a jackshaft. Infinte speed adjustment at the twist of a knob and reversing for tapping holes. Makes a old drill a joy to use. A VFD would get you the same results. I have several VFD drives, the DC option I think is cheaper though. I bought my setup for about $75 on eBay Quote Link to comment Share on other sites More sharing options...
arftist Posted July 14, 2011 Share Posted July 14, 2011 Yep, I'd say jackshaft, make a larger mounting plate, put the step pulley that's on the motor on a jackshaft in the same position that it's in now, and mount the motor to the side and up a bit, with a small pulley on it to the largest step of the back pulley. You can also leave the motor right where it is and mount the jack shaft on a stand off to the side and ahead (between the two existing pulleys. The simplest way is a stub shaft sticking up, and a third step pulley with bronze bearings pressed in and dropped over the stub shaft. The stub shaft must be aranged to pivot away from the spindle pully for belt tension and the motor step pulley can be flipped over. Quote Link to comment Share on other sites More sharing options...
knots Posted July 14, 2011 Share Posted July 14, 2011 One of my drill presses has a counter shaft mounted in the top of the drill press column. It consists of a plug that is machined for a slip fit into the top of the column. This plug is drilled and fitted for an eccentric shaft which carries a multi-groove idler sheave. The motor drives this sheave and a second belt which drives the Drill press spindle. The belt between the spindle and the idler must be carefully fitted because there is not much tensioning adjustment , but it works. I never have figured out the minimum spindle speed because I have fitted my Clausing drill press with VFD and use it when I need to a slow spindle. One problem I think that I see using this method with this drill press is that it appears that the drill table is missing on your press and to be applied the drill press head needs to be up at the top of the column. Quote Link to comment Share on other sites More sharing options...
fciron Posted July 14, 2011 Share Posted July 14, 2011 MB, are you sure that little #2 morse taper is up to the task of pushing some big drills? Why are you slowing it down? That will have some bearing on the correct solution. lewis Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted July 14, 2011 Share Posted July 14, 2011 I know I have, like, 16 speeds on mine with all the different belt combinations. Think I use two of them ...........too fast and too slow. If you can figure out a way to mount another motor off to the side, you could put a small pulley on it and run a belt to the top of your current motor pulley. Then your current motor would become a jackshaft when you need lower speeds. The second motor would not have to be very big with all that reduction, maybe 1/2 HP. Looks like you could make a slick mount that clamps on the center column, way up high and you could swing it to tighten the belt. Would let you raise and lower it to line up with different pulley grooves too. VFD's have their place and I love them, but they don't add any torque. When you use a 2:1 belt reduction you are cutting the speed in half, but you are also DOUBLING the torque. Works great in a drill press because large drills require lower speed AND more torque. Quote Link to comment Share on other sites More sharing options...
mat Posted July 15, 2011 Share Posted July 15, 2011 try this. http://www.metalwebnews.com/mr.html scroll down to "how to bore large holes" there is a pdf to down load on this very thing Quote Link to comment Share on other sites More sharing options...
macbruce Posted July 15, 2011 Author Share Posted July 15, 2011 Thanks for the wealth of info. I think using the old 3ph motor as a jack shaft is brilliant, cause I was gonna dump it anyway.......Now I can mount the mtr round back and not interfere with the cover and all that, since it's bolted to a 200lb die plate it won't be tippy. This method will I think allow me to spend less MONEY cause I can cobble it together mostly with what I have. I can't wait to tinker with it only I'm 1,500mi from home outside of Tacoma at a wedding.......wish I could stay for the conference here in August The drill is needed to fill part of the hole left when I had to sell the Bridgeport.........or at least allow me to drill larger holes than my 1/2'' vary speed Powermatic. Ya all know that they make large bits with 1/2'' shanks but the Powermatic isn't fooled by this intrusion, if I could just drill say a 1'' hole without abusing the limits it would help allot.....Thanks all (how did I ever manage without the internet)B) Quote Link to comment Share on other sites More sharing options...
monstermetal Posted July 15, 2011 Share Posted July 15, 2011 Hey man you should make an effort of come check out my shop! I am 15 minutes kind of North east of Tacoma in Auburn I'll shoot you a email with a phone number.. Quote Link to comment Share on other sites More sharing options...
macbruce Posted September 19, 2011 Author Share Posted September 19, 2011 Works like a dream......Found a 3/4 hp mtr with 5/8 shaft , the same as the original motor which I used as the driver since I have a small ph converter.......A piece of salvaged 1/4'' plate for the adapter and except for some new belts, nothing out of pocket......slow speed is now 120rpm and I'm not even using the bottom pulley on the quill......Don't know what high speed is but I'm sure it will fill the gap in between my Powermatic and it,which has a slow speed of 480rpm.....It drilled a 3/4'' hole with ease even with the worn out step pulley on the idler motor which, when I increased pressure it would slip...One of the cool things is that I can still simply lift the plate that the motors are mounted to, to change speeds.......You guys are great! Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted September 19, 2011 Share Posted September 19, 2011 See! Ya already had a jackshaft and just didn't know it! Quote Link to comment Share on other sites More sharing options...
macbruce Posted September 21, 2011 Author Share Posted September 21, 2011 Just a follow up.........With a little more tweaking I got the speeds to 60-875 rpm. The largest hole I can do so far is 2 3/8'' through 1'' plate! Quote Link to comment Share on other sites More sharing options...
Fosterob Posted September 21, 2011 Share Posted September 21, 2011 It is good you went with the jack shaft instead of DC. DC looses HP as the speed drops. I also did not see the cooling water pipe going to the new motor on your drill press, it says "STREAM COOLED" so you must live by a creek :lol: Rob Quote Link to comment Share on other sites More sharing options...
macbruce Posted September 21, 2011 Author Share Posted September 21, 2011 It is good you went with the jack shaft instead of DC. DC looses HP as the speed drops. I also did not see the cooling water pipe going to the new motor on your drill press, it says "STREAM COOLED" so you must live by a creek :lol: Rob Lotsa water for sure for the 2 3/8'' holes...... Quote Link to comment Share on other sites More sharing options...
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