want to be able to reverse HF drill press

On Fri, 05 Dec 2003 11:58:17 GMT, Karl Vorwerk put forth the notion that...

If this is a capacitor-start single phase induction motor, it's possible, but it's a bit tricky. You have to take the motor apart, cut the leads going to the start coils, and run them through a DPDT switch in such a manner that the polarity of the start coils with respect to the run coils is the same when the switch is in one position, and opposite when it's in the other position. If you don't know much about motor wiring, I'd recommend you have a motor rewinding shop do this for you.

If you put much load on it, you could unscrew your chuck.

I'd like to be able to reverse my HF drill press when I use it for sharpening knives, etc ^^^^^^^^^^ If it's for occasional, light-duty use, you might consider just crossing the belt. You will certainly need a longer belt, and if possible, I would get a round one. Don't ask me where. If you use link-belting, I have a hunch it will run better crossed, and you will be able to play with the length without having to buy several different belts.

I already know you purists won't like this idea.

I'm curious why you need it running backwards while sharpening knives?

Maybe you could screw the base to something overhead and run it upside down. That'd reverse the rotation as you face it. (Ducking...)

Jeff

-- Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone to place the blame on."

%99.9 of DPs use tapered chucks, not threaded.

GTO(John)

Thanks for the replies. The reason for reversing would be to make it easier to sharpen the other side. Yes it is a capacitor start so that sounds like more trouble than it would be worth to me. I'm to lazy to flip the drill press. It is a taper chuck so I'm not to worried about that. I'd thought about twisting the belt. Thinking more about it, I may try finding something around here to use as a longer belt. Not as nice as throwing a switch but cheap and simple for occasional use. Thanks the replies helped. Karl

You could simply hang a 3 ph motor on it.

Gunner

No 220-pound thug can threaten the well-being or dignity of a 110-pound woman who has two pounds of iron to even things out. Is that evil? Is that wrong? People who object to weapons aren't abolishing violence, they're begging for the rule of brute force, when the biggest, strongest animals among men were always automatically "right". Guns end that, and social democracy is a hollow farce without an armed populace to make it work. - L. Neil Smith

Basically you need to bring out the four leads - two that are the starting windings, and the two wires that feed them. Then you put a DPDT switch wired up as a reversing switch. If you cannot figure out what's inside the motor, you could hire an electrician to go into it and install a reversing switch.

Because the motors on those drill presses are inexpensive it may be a tough job to cut and splice into the starting windings, and bring out the leads in an acceptable fashion, so they are mechanically protected.

Jim

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Karl Vorwerk wrote: The reason for reversing would be to make it easier to sharpen the other side. (clip) I'm to lazy to flip the drill press (clip) ^^^^^^^^^^^^ How about flipping the knife?

I do that if I'm using a drumsander on it for sharpening but I really like the flat grinder in "The Workshop Companion" "Sharpening" book. I recommend this book by the way. It's mainly for woodworkers but has plans for jigs and machines. Having just looked at the book. I find that their flat grinder doesn't reverse. This is giving me the urge to build a dedicated knife sharpener. I'd rather spend more time making something than sharpening them with my diamond stones by hand. My motto is "If you can't do it with power did you really need to do it at all?" Karl

I can see this. Now I just need to figure out where to put the 3 phase inverter in my studio apartment. Those things hurt if you kick them when you're getting out of the shower. Karl

A Phaso-matic is about the size of a bible. Costs $75, and a small 3 ph motor used is $5.

Keep in mind that a 1/2hp 3 ph motor has the power equiv of about a

3/4-1hp single phase 110vt motor.

A small step up transformer...1.8 kv, a Phasomatic and a motor shouldnt cost you more than a $100USD if bought on the spur of the moment and a bit of searching will get it down to half that if all bought used.

Another option would be one of the small fractional horsepower VFDs on ebay.. lets say 1/4hp. They tend to go for under $100USD, and turns your drill press into a variable speed drill press, with full reverse.

Such as this:

?ViewItem&item=2577813425&category=42895 Gunner

No 220-pound thug can threaten the well-being or dignity of a 110-pound woman who has two pounds of iron to even things out. Is that evil? Is that wrong? People who object to weapons aren't abolishing violence, they're begging for the rule of brute force, when the biggest, strongest animals among men were always automatically "right". Guns end that, and social democracy is a hollow farce without an armed populace to make it work. - L. Neil Smith

Plus, they run off of 120. But they do require a new three phase motor. The combination of a vfd and three phase motor on a drill press is nearly unbeatable.

If all he really requires is a reversing motor, then simply re-wire the existing motor to reverse. If it isn't a capacitor start motor, then I would replace it with either induction-repulstion, or capacitor start, and wire it with a reversing switch.

Again, if he can't figure out how to do this, then he probably cannot deal with the VFD approach either, and would simply be best off hiring a knowledgeable electrician to re-wire or replace the motor.

Jim

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[ ... ]

Another consideration, which I have not yet seen mentioned, is that a drill press with a reversing switch can't use the nice keyless chucks (Albrecht and the various clones), as they self-tighten in forward, but *loosen* in reverse. (There are special versions which have locks to prevent that, but I would consider a standard keyed chuck of the Jacobs pattern to be a better choice with a reversible drill.)

Enjoy, DoN.

Cool. I probably won't get it for my drill press but I'm going to keep the info around in case I need it for something else. I didn't realize there were small inverters for 3 phase. I've got a VFD plunge router but I haven't seen them as motors. I need to get out more. Thanks Karl

Well then time to learn. The audel's book is an *excellent* reference, and most libraries have them.

Can you tell if the existing motor is capacitor start? It would have an extra housing grown on the side of the motor, and you will hear a 'click' as the motor comes up to speed.

Jim

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On Mon, 08 Dec 2003 11:00:17 GMT, Karl Vorwerk put forth the notion that...

Here's a very good 3 HP phase converter that I make and sell on eBay, if you're interested:

It can also be used as a static converter in most conditions if you don't add the idler motor.

It's a capacitor start. I looked up the wiring diagram and how to reverse it online last night. Time to go buy a switch and do some motor surgery. Karl

Karl