Van Norman No. 12 Table Feed Motor

I have a late 1030's VN-12 which I'm both using and reconditioning. I know for a fact that this machine spent an extended period of time outdoors prior to getting it. The feed drive motor is the original, but has the remnants of about 7K layers of paints which render the builders tag unreadable despite attempts to cajole it into revealing its secrets. I believe it's a 1/4 HP plane bearing motor. While it does start and run, it soon heats up and slows down after a couple minutes idling (without engaging the feed gears).

Does anyone have a frame size and rpm for this motor so I can figure out a replacement? I'm not concerned with originality, more function. Am running of a static PC which runs the Baldor spindle drive motor like a champ, the machine is otherwise what one would call "well used" and came from a production environment where it pretty much ran the same slotting operation since Hector was a pup, so it is likely that this old motor is just worn out. Any help would be appreciated.

I'll see if I can find something for you this evening. I believe you are correct that it is 1/4 HP, and it is 3-phase.

Thanks! I know I can back figure it or at least improvise an adapter if it's not the same exact frame size. Mostly it's the RPM I want to be sure to match because otherwise it's an issue of the feed speeds being fairly accurate.

According to my #12 VN brochure, the feed motor is supposed to be a 1/4 hp, 1725 RPM motor. You could measure the distance from the motor base to the centerline of the shaft and match it up to the NEMA specs. I'd bet it's a 56 frame motor.

swarfmeister said:

I have a late 1030's VN-12 which I'm both using and reconditioning. ... The feed drive motor is the original, ... I believe it's a 1/4 HP plane bearing motor. While it does start and run, it soon heats up and slows down after a couple minutes idling (without engaging the feed gears).

Does anyone have a frame size and rpm for this motor so I can figure out a replacement? I'm not concerned with originality, more function. Am running of a static PC which runs the Baldor spindle drive motor like a champ, ... it is likely that this old motor is just worn out. ...

Click to expand...

Do you mean 1930s? What's the serial number?

Here's the name plate for the feed motor on my 1944 No. 12, s/n 7689:


It's 3-phase, 1/4 HP, 1725 RPM, frame 145K and has ball bearings. Your motor probably just needs bearings; why don't you start there first? Do you still have the silent chain drive?

If your static phase-converter doesn't have run capacitors, your motors are limping along on two phases, which will contribute to them heating up. Some simple Ohmmeter tests will tell you if there's anything badly wrong with the windings.

Cal
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The motor has two oilers at the top rather than grease fittings so I assume that it's plane bearing. I'll try and grab the S/N tonight. The spindle motor is a late model baldor 1-1/2 HP brake motor, and shows no heating issues. The drive motor starts and runs fine for a couple minutes, but the bearing end opposite the drive sheave heats up first and the motor starts to gradually slow down, so I'm not inclined to think its the SPC. The chain drive was replaced by a v-belt drive and the motor was spacered down in order to get in the neighborhood of proper belt tension. I replaced the spacered bolts with threaded rods with nuts top and bottom. The machine came out of Southwick and Meister where they had a whole department of mostly No. 12's doing keyway slotting on collets, so it ran pretty much one job in one fixture at one speed. It took a while to limber up the feed gearbox and the speed selection gearbox, and also a work in progress getting all the rusted solid steel chips out of the table T-Slots. The table is a mess, but okay with a vise. The saddle is bellmouthed .018 to .020 on the right hand side but it still tracks okay if you're not pushing it. I was lucky enough to get a freshly tercited gib along with a bunch of other replacement parts when I got the machine, but the saddle is going to need to be scraped back in within reason.

My Dad apprenticed at Van Norman at the age of 14, so it is likely he was there when this machine was made, which I think is cool. I'm also teaching my youngest son some machinist skills, and I've put a 3 axis DRO on the machine to make things easier for him to grasp. I'll pull the motor off this weekend and tear into it more. This sat out in the weather for a year or so, which some electric motors are okay with and some aren't. The machine was not particularly well maintained, but it was kept running within tolerance, which I think is a tribute to the design. Do that to a bridgeport (no offense, I work on them everyday), and you'd have a boat anchor on your hands.

Sorry, I can't get to the name plate without taking the motor off. Hopefully, these other replies will help. My notes show that the bearings in the table feed motor were New Departure C8503, sealed on one side, and that I replaced them 18 years ago with bearings labeled MRC 8503 H401. The housing on my motor has grease fittings. The mill is 1947 vintage.

@Cal S/N 5042-12

I tried using a lighter 10w oil in the cups and am getting longer run times and less heat build up. I think this may be a case of just running it in and flushing out the laquer that has built up there. I just ran it at idle for nearly 10 minutes without much slowdown and pretty even heat buildup between the end bearings.

Take the motor apart and clean it out. There are four parts to a 3ph motor, two end bells, stator/housing and rotor. You can't screw it up unless you take a hammer and chisel to the windings. Don't replace that motor unless you absolutely HAVE to. Modern motors are nowhere near as under-rated or durable. You can actually flush the bearings out with kerosene and then oil with a good spindle oil. Use non-detergent single wt oil. Hydraulic oil is also a good substitute.