Drill Press Motor

[Frank Hagan]

My old drill press motor is giving up the ghost. I have to hand-spin the chuck to get it to start anymore.

Not sure where you get replacement motors ... the motor itself has a 1/2" shaft with a flat on it, and a stepped pulley is installed on it with an allen screw that secures it. Its an old Craftsman motor that was added to the DP sometime in the 1960's, I think. Here's what the motor label says:

HP: 1/2
RPM: 1750
VOLTS: 115
AMPS: 6.7
TYPE: CNB
Model: 115.5829

I don't see anywhere on the lable that has a service factor, and I have no idea what type "CNB" means.

So, do I just find a 1/2 HP motor with a 1/2" shaft to replace it? Or is that amp rating an indication that I should replace it with a 3/4 HP motor if I am using an inexpensive motor with a low service factor?

[Brian Hale]

I'd replace it with a motor that has an amp rating the same or bigger than what's on it now. If you never complained about lack of power in the past, get another 6-7 amp model.

I'm not sure what CNB stands for, perhaps it's an indication of the frame shape and size?

Brian :)

[Scott Parks]

Same story here with my DP.... Since this is a low duty item for me, I'm :oconsidering:o looking at a replacement from harbor freight. Mine is a Jet 1 1/2 hp model, so a quality replacement motor is about $350+, but a HF is about $90. So in other words, I can buy 4 replacement motors for the price of one. Since it is a low use item, in a hobbiest environment, if I can get 5 years out of one motor it will take me 20 years of HF motors to one american made motor.... .02

Another option I have.... I've got a washing machine motor that I might put on it for temporary use. My dad has been running a washing machine motor on his DP since 1989 in his home machinist shop....

[Frank Hagan]

I had forgotten about Harbor Freight. That may be an option, since like Scott, my DP is a low-use item. I have two of their stores near me, and another one near my office.

The problem I was running into on-line was matching up the specs on this motor since it doesn't have the frame number on the label. Northern Tool had one that was about $90, but I wasn't positive about the shaft itself (it was 1/2", but didn't look like it had a flat on it.)

[tod evans]

I had forgotten about Harbor Freight. That may be an option, since like Scott, my DP is a low-use item. I have two of their stores near me, and another one near my office.

The problem I was running into on-line was matching up the specs on this motor since it doesn't have the frame number on the label. Northern Tool had one that was about $90, but I wasn't positive about the shaft itself (it was 1/2", but didn't look like it had a flat on it.)

flat??? gotta grinder? easy fix:)

[Wes Bischel]

Frank,

Two things - 1) Does the motor have the humps for the start and run capacitors on the sides? If so, it sounds like the classic symptoms of a start capacitor gone bad. You can usually see if they have gone bad, and new capacitors are cheap - less than $10 (don't hold me to that, it's been a while since I bought one).

2) Check ebay for a motor. I have picked up new Baldor motors for less than $100 including shipping. The deals are out there if you look hard enough.

FWIW,

Wes

[Rob Russell]

The key thing to look for on the motor is the frame size. It's probably a 56, with a "C", "J" or other letter after the 56. A 56C, for example, is a specific size and the C means face mount.

The shaft size and diameter, key size, etc. are based on the frame size.

[Frank Chaffee]

Frank,
If you go to www.mcmaster.com and page through the motor section of the catalog beginning on page 911 you will be able to find the frame number of your motor.
Frank

[Allen Bookout]

No mater where you end up getting your motor make sure it either 1. turns the correct direction for your drill press or 2. can be wired to run either direction so that you can change it if necessary. Some motors cannot be wired to run the other direction sucessfully.

If you have a Northern Tool near you they carry Lesson motors (Made in the USA) at a pretty reasonable price. They are good motors. Buy it from the store instead of ordering it because I was sent one that the specs were wrong and I had to pay shipping back plus it was a couple of months getting my money back. I guess that the odds of my problem are pretty slim come to think about it. So if they had just what I needed on line I guess that I would order it again.

Grizzly handles pretty good motors that are imported at a pretty good price also. I am running one of their 2hp motors on my bandsaw and have had good luck with it.

It might not cost much more to step up to a little larger horsepower. One half is a little weak I think, even if it's a low use item.

[Ken Garlock]

Frank, check out Electric Motor Warehouse (http://www.electricmotorwarehouse.com/) in Michigan. I bought my cyclone motor from them. They carry name brand motors like Lesson, Baldor, Century, Dayton, etc. Example, 1/2 hp Lesson - $104, 1/2 hp Baldor - $124.

[Frank Hagan]

Frank,

Two things - 1) Does the motor have the humps for the start and run capacitors on the sides? If so, it sounds like the classic symptoms of a start capacitor gone bad. You can usually see if they have gone bad, and new capacitors are cheap - less than $10 (don't hold me to that, it's been a while since I bought one).


It does sound like a start capacitor, but the capacitor on this motor is a large, flat one that is mounted within the foot of the motor. I've never seen anything like it ... its about 3" wide x 4" long and 3/4" thick. All of the motor capacitors I've seen are round and fit under a "dog house" on the motor casing.

[Frank Chaffee]

Thanks Ken,
I have put that url in Favorites myself.
Now if I will just backup before my next hard drive crash...
I don't buy from McMC or Graingers when I can help it, but they are each a ready resource for info and charts.
Frank (C.)

Ken, I really dig your signature line, but what does it mean???

[Frank Hagan]

The key thing to look for on the motor is the frame size. It's probably a 56, with a "C", "J" or other letter after the 56. A 56C, for example, is a specific size and the C means face mount.

The shaft size and diameter, key size, etc. are based on the frame size.

No frame size on the motor label. The only label on the motor is an aluminum plate about 2 x 3 that also doesn't have the phase or service factor. The only information on the motor is:

HP: 1/2
RPM: 1750
VOLTS: 115
AMPS: 6.7
TYPE: CNB
Model: 115.5829

Its a Craftsman, so I suspect its something Sears sold without adhering to the norm in marking motors. I did look at the motors on display at Harbor Freight, and they were all 5/8" shafts. I could use one of those if I get a new 5-step pulley (which might be more expensive than the motor!)

How is motor rotation described? If I have the motor on the bench, with the shaft facing me, and turn it on, is "CCW" rotation to the left as you would expect, or to the right? Or is the rotation determined while you have the switch end of the motor pointing at you, with the shaft pointing away?

[Allen Bookout]

With the pulley shaft facing you and the rotation is clockwise it is right hand. If it is counterclockwise it is left hand.

If you have to get a step pulley they are sometimes hard to find depending on where you live. Here is where I got my last one: http://doityourself.com/shop/beltpulleybearing.htm

[Ken Garlock]

Thanks Ken,
I have put that url in Favorites myself.
Now if I will just backup before my next hard drive crash...
I don't buy from McMC or Graingers when I can help it, but they are each a ready resource for info and charts.
Frank (C.)

Ken, I really dig your signiture line, but what does it mean???

Eschew: to avoid doing or using something on principle or as a matter of course (Microsoft® Encarta®)

Obfuscation: to make something obscure or unclear, especially by making it unnecessarily complicated (Microsoft® Encarta®)

It is a play on words by using arcane/obscure words to warn against using arcane/obscure words. :eek: :rolleyes:

[Allen Bookout]

Ken,

I am glad to see Microsoft associated with the word Eschew. To bad that there is not more of us that feel that way. Enough said! --- or --- Enough said? Allen

[Stephen Dixon]

If the shaft is 1/2" then the motor is most likely a 48 Frame. I can't find my pocket manual which lists all the frame dimensions, but I know that a 1/2" shaft is 48, and a 5/8" shaft is a 56 frame.
Steve

[Frank Hagan]

With the pulley shaft facing you and the rotation is clockwise it is right hand. If it is counterclockwise it is left hand.

If you have to get a step pulley they are sometimes hard to find depending on where you live. Here is where I got my last one: http://doityourself.com/shop/beltpulleybearing.htm

Thanks, Allen! They aren't as expensive as I thought ... I ordered one tonight, and I'll get a 3/4 HP 48 frame motor from HF, and still be money ahead.

[Steve Stube]

Frank, I would replace the capacitor (should be about $10.00). If that is the old Craftsman equipped with ball bearings it is probably better than most any motor you would/could replace it with. If you need specific help PM me.

[Frank Hagan]

Well, I went ahead and got the 5/8" 5-step pulley from DIY Warehouse for $21, and then went searching for a motor from the links in this thread. I searched Electric Motor Warehouse pretty well. Then I tried Amazon.com, and the search brought up a 3/4 HP three phase motor (for search terms "1/2 HP 1 PH" ... weird). But then I noted that the "bread crumb trail" up at the top showed the section in Amazon.com to be "Tools and Hardware > Agricultural", so I clicked on that.

There are quite a few TEFC LEESON motors on sale right now. See http://www.amazon.com/gp/search/102-2675335-0039353?%5Fencoding=UTF8&search-alias=tools&field-brandtextbin=Agricultural

There was a 1/2 HP 115/208-230 motor that pulls 8.4 amps on 115v that I snapped up for $121, including $22 shipping. Because the old motor was rated with 1/2 HP, no service factor on the label and 6.7 amps, I think its what we used to call an "uprate" ... with a service factor of 1.0 ... and the new one will be equivalent to a 3/4 HP uprate. The listing didn't give the service factor, but I suspect it's a 1.3 or 1.5 on the LEESON motor.

The funny thing is they are being sold by Electric Motor Warehouse. So they must have a "clearance items" deal with Amazon.com that they aren't doing on their own site. It pays to shop around.

[Edit - I did find the motor listed on Electric Motor Warehouse's site, in the "Farm Duty" section, with the Amazon.com price, so my supposition was wrong. But I didn't think to look for deals in "Farm Duty" motors, and was almost ready to pay nearly as much for a ODP style motor].

[Frank Hagan]

Frank, I would replace the capacitor (should be about $10.00). If that is the old Craftsman equipped with ball bearings it is probably better than most any motor you would/could replace it with. If you need specific help PM me.

I did get the specs off the capacitor, but went ahead and ordered another motor. I plan to use the motor for a shop built sander project.

The cap is weird on this one ... its mounted inside a recess in the foot, and is a "sardine can" style 3 1/8" wide by 4 7/8" long and 5/8" thick. Labeling on it is:

5205058
124 - 165 MFD
125 VAC AEROVOX
Made in USA R09

Aerovox no longer lists it in their system as far as I can see. So in order to use this motor, I think I'll need to buy a regular start capacitor and mount it on the outside in a doghouse like you see on motors today.

But I can't find a 124 - 165 MFD capacitor out there ... there are 124 - 156 MFD, and some others. I'm not sure how the range in "microfarads" affects the jolt it gives the motor to help it start.

So here's my question: can I use a 124 - 156 MFD start capacitor?

[Stephen Dixon]

The 124 to 156 mfd capacitor will work fine. There is very little difference in those ratings.

[Bill Turpin]

Start caps are round, black, plastic and filled with a salt solution. Run caps are flattened ovals, grey, metal , and filled with oil. Bad caps usually go bad because of over-heating. Start caps boil the solution and blow out the brown resin plug that is between the terminals. Run caps get swollen into non flattened ovals. Check the start switch contacts that are inside the end bell on the non-shaft end. Clean or very lightly file them if burnt. Blow out with air to make sure centrifugal weight is free to move. Twenty minutes of simple housekeeping can save the price of a motor.

Bill in WNC mountains