drill press, slow down

[brownbagg]

i remember the discussion we had couple weeks ago, the pulley, the modified kit, the just buy a bigger drill one, and the taiwan ***** discussion.

well while driving on a road trip, i had a thinking. why cant i just remove the triple deck pulley i have and replace with one i need, its that possible, just one, one big pulley and build something to keep the hair i got , away from it

im just thinking here.

 

[Earp69]

I did this with mine, but it's using a 3 phase motor and it's powered by a variable speed drive I use to control speed. I have enough torque to drill 1.25 comfortably, using an adjustable belt from harbor freight.

 

[shawhite]

Anything is possible. Question is will you have enough torque at the low speed. But honestly the best solution would be covert to 3ph with vfd or go DC with a treadmill motor swap.

 

[lilredex]

You could just look for one already with the intermediate pulley. Lots of them around, and was my solution.

 

[tool_scrounge]

For retrofit to lower speeds, I would make a copy of the Cardinal slow speed drive with spacers, ground shaft and pillow blocks.

http://vintagemachinery.org/pubs/10733/17012.pdf

 

[Earp69]

For retrofit to lower speeds, I would make a copy of the Cardinal slow speed drive with spacers, ground shaft and pillow blocks.

http://vintagemachinery.org/pubs/10733/17012.pdf

This is an awesome and simply enough idea

 

[timgunn1962]

The easiest way is probably to replace the motor with a 3-phase one, preferably with a higher pole count and lower speed, and drive it with a VFD.

If you have a 4-pole motor (a little less than 1800 RPM on 60 Hz mains) and fit a 6-pole (a little less than 1200 RPM on 60 Hz mains) of the same frame size (so the motor swap is simple) and power rating, you'll have one and a half times the torque straight away. You can vary the speed downwards without any reduction in torque. Speed at 60 Hz will be 2/3rds of the original, but you can increase the speed to the original speed by running the VFD to 90 Hz and, while the torque will reduce from its new, increased, peak, you'll still have the original torque and power at the original speeds.

Typically, you'll be able to run down to about 10 Hz smoothly (a little under 200 motor RPM on a 6-pole motor) If you can get an 8-pole ( a little under 750 RPM) motor with more torque in the same frame size, the win is even bigger.

The Cardinal solution is very good if you are more comfortable with mechanical stuff than electrical/electronic stuff. It'll give a torque increase along with the speed reduction (definitely A Good Thing), but will lose the high-speed capability your drill currently has.

 

[The Cobbler]

For retrofit to lower speeds, I would make a copy of the Cardinal slow speed drive with spacers, ground shaft and pillow blocks.

http://vintagemachinery.org/pubs/10733/17012.pdf

This is an awesome and simply enough idea

I agree it would be quite easy to make with a simple mandrel. that's a great idea

 

[timgunn1962]

Sorry, should have read the original post more carefully. You can run at a single speed: bigger spindle pulley and/or smaller motor pulley. It'll limit you to one speed. As the reduction ratio increases, you'll get less "wrap" on the motor pulley and at some point you'll find the belt slips under load as a result. You can increase the centre-centre distance to overcome this to some degree, but I've not got enough workshop space to lose any of it to longer belts and I'm guessing you haven't either. I'd use Cast Iron pulleys, not Aluminium, and modern Cogged Raw Edge wedge belts: the cogging/notching allows the belts to wrap round a smaller pulley, so you'll be able to get more reduction in the available space. Cast Iron pulleys give better grip than Al, IME. Modern Wedge belts will transmit way more torque than the original Vee belts of the 1950s and 60s.

 

[ez-duzit]

3-phase drill presses are plentiful and very cheap to buy on the used market. And they generally already have the slow speed capability.

 

[brownbagg]

You could just look for one already with the intermediate pulley. Lots of them around, and was my solution.

i got that one, I want go lower

 

[brownbagg]

nobody answer my question. why cant i just put a single bigger pulley on the splindle/
one speed drill press. instead of a four which it haves, put an eight on it

 

[Maui]

For retrofit to lower speeds, I would make a copy of the Cardinal slow speed drive with spacers, ground shaft and pillow blocks.

http://vintagemachinery.org/pubs/10733/17012.pdf

That is a great idea! I may build one of those from scratch to try it. I certainly have everything I need.

 

[isb cornbinder]

This may not be "the answer" to the original question, but it is the answer I came up with to get my 100-year-old Cannedy Auto drill-press to run slow. I had to turn cone-pulleys and a flat belt pulley. The whole collection of bits and pieces are on shafts and pillow block bearings. The final drive is a leather flat-belt.
I like my shop time to include making parts. Having a lathe or two makes all the difference.
Is this a little over-the-top solution? I think so. I enjoyed making the parts and I would do it again.

 

[tool_scrounge]

nobody answer my question. why cant i just put a single bigger pulley on the splindle/
one speed drill press. instead of a four which it haves, put an eight on it

Can you do it? Sure. But all commercial prodcuts are designed to meet requirements AND a price point. So if the requirement were to drill half inch holes in cast iron, it may have been designed to drill slightly larger holes with an acceptable lifespan (whatever that may be). But if you want to greatly slow it down so you can drill big holes in metal, the added stress is probably going to break something.

Once for fun I put a third pulley and a industrial DC motor on a parts donor bench drill press. It would run happily at 60 rpm with plenty or torque. The problem was other components of the drill press could not hold up to the added stresses. Fun experiment. But I was not surprised at the end result.

 

[cvairwerks]

Sure, you can go single pulley. When you do, it limits both the bit size you can run and the material. Different materials and different bit sizes require various speeds for efficient cutting and managing bit wear. It would be like replacing your car with a lawn tractor....both will get you where you need to go, but with wildly different efficiencies.

 

[timgunn1962]

Sorry, should have read the original post more carefully. You can run at a single speed: bigger spindle pulley and/or smaller motor pulley. It'll limit you to one speed. As the reduction ratio increases, you'll get less "wrap" on the motor pulley and at some point you'll find the belt slips under load as a result. You can increase the centre-centre distance to overcome this to some degree, but I've not got enough workshop space to lose any of it to longer belts and I'm guessing you haven't either. I'd use Cast Iron pulleys, not Aluminium, and modern Cogged Raw Edge wedge belts: the cogging/notching allows the belts to wrap round a smaller pulley, so you'll be able to get more reduction in the available space. Cast Iron pulleys give better grip than Al, IME. Modern Wedge belts will transmit way more torque than the original Vee belts of the 1950s and 60s.

nobody answer my question. why cant i just put a single bigger pulley on the splindle/
one speed drill press. instead of a four which it haves, put an eight on it

You can, as I'd posted four hours before.

Trying to help you out, here: At present, it seems you have a 4" pulley on the spindle and you want to go to 8" to halve the speed? If you just change the spindle pulley, the angle over which the belt is in contact with the motor pulley will reduce. If you are looking for low speed and high torque, the most likely place you'll run into a limit is with the original (Aluminium?) motor pulley and (Vee?) belt slipping.

You've not really given us a lot of information to go on: Why do you want to run slow? To drill bigger holes, or to drill holes in heat-sensitive materials, for example?

Most of us on here would instinctively want to extend the capability of an existing machine and that's the way my thought process was going when I saw the original post. If you are happy to make it a single-purpose machine with only one speed, and deal with anything else that needs doing as a result (you've already identified the guarding), the pulley change option will work fine. Subject of course to everything else being able to cope with the (potentially higher) loads.

 

[isb cornbinder]

About 10 years ago, I bought the remaining stock of reconditioned BOSTON GEAR speed reduction gear boxes.
For my $100 I got five good units and one with a broken input shaft. I sold a few to guys who were wanting to reduce the input rpm on their drill presses.
I know the new prices for these gearboxes can top a grand. I saved two for myself and a future project I have not thought of yet. I got $250, each, for the three I sold.
Keep your eyes on Craigslist. CL has come through for me many times.
I made a chain a sprocket drive for a beading machine. The beading machine is driven by an 18-volt Milwaukee drill. The collection of bits and pieces make up the foot control for the drill.
We are lucky to have PRINCESS AUTO. This store stocks a large variety.
With little or no information to go on, I am thinking that you might be able to use a VFD