# Drill Press Speed Adjustment



## courtjester (Jul 11, 2009)

I am looking for an article about a mechanical Speed changer for a Drill Press that was in Home Shop Machinist or Projects in metal. I have spent a day looking threw all the issues I have from 1985 on but could not find it. I do know they did an article about making one I just cannot find it. You may call it something else. 
Basically it is a double pulley that is manually adjustable by moving a control arm. As the arm is moved the belt tension causes the center plate of the pulley to move up or down changing the size of each portion of the pulley. 
If anybody has info about one of these I would be very thankfull. I saw one years ago on an old drill press in a machine shop.
Thanks 
Tom


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## rake60 (Jul 12, 2009)

Welcome to HMEM Tom.

That appears to be a variable speed pulley set up that is very 
similar to the "shift on the fly" system used on many lawn and
garden tractors today. Interesting idea!

Rick


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## steamer (Jul 12, 2009)

Logan uses that variable speed adjustment on their lathes


Check out Tony's site on the Logan.

http://www.lathes.co.uk/logan/page4.html

Additionally, I attached to this post a copy of the Army manual for my lathe


It has an exploded view of the assembly.

It's on the post page in small text.....keep looking you will find it.

Dave 

View attachment powermaticarmy12.pdf


View attachment powermaticarmy12.pdf


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## arnoldb (Jul 14, 2009)

That's an interesting mechanism!

And then I found this in the pdf Dave attached (under the The Friction Clutch section):



> adjusted at the factory to feed the *carnage *longitudinally with a thrust of 800 pounds.


 Rof}

Must be the Army way of doing things ;D


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## reggie98 (Aug 3, 2009)

You could just put a three phase motor on the DP and use a VFD to control the speed or even a DC motor from a treadmill and use a variable voltage DC power supply. Another option can be found on some old DP(s), a third cone pulley mounted on the column.
 Or look at it this way, before belt drives with variable pitch pulleys were available, machinists were able to produce parts with machines that had just 4 or 5 speeds. It's all in the choice of speeds and feeds.


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## bmuss51 (Aug 7, 2009)

as for another idea to change dp;s speed is what i did .at least that is if you are talking about a floor dp with up to a 3/4 hp motor.
 what i did was swap out the stock motor and mounted a washing machine motor that has 3 speeds which i got at a junk yard for about $3. and added a 3 position switch along with another switch for the off. and then i found the correct speed combination on the belt drive that would suit the most used speeds. so now all i have to do is select the speed toggle switch to the speed i want and turn it on with the other switch. and what i use the most is about 400rpm,750rpm and 950rpm. and all i have to do is just flip the speed toggle with no belt change. but the 1 down side is if you feed the drill to fast the motor will kick out, and the drill gets stuck . to point that you have to turn the dp off and back out the drill before you can continue. but if you pay attention you will hear the spindle speed drop as a warning.


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## kustomkb (Aug 7, 2009)

> washing machine motor that has 3 speeds



Great Idea! 

Must go to junk yard now...


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## Brian Rupnow (Aug 7, 2009)

look on this web page.--They have exactly what you are asking about. I used one 2 years ago on a machine I designed.---Brian
http://www.speedselector.com/


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