harig 6x18 SG spindle apparently needs new bearings - recommendations for service?

My 6x18 harig SG suddenly started making a high, dissonant, screeching noise yesterday, which we presume indicates spindle bearing failure.

With a lot of help from friends, the spindle and motor have been removed from the machine.

Any recommendations for a service shop to replace the (presumably bad) bearings? Someplace in Seattle metro would be very nice.

Is there any reason the spindle and motor would be shipped off together, or would one normally decouple the spindle from the motor and just send that out?

[Earlier threads have suggested this kind of bearing change is above my pay grade.... Or not?]

Post some pics of the spindle assembly, and did you determine which end was making the noise?

One reason to send the motor along with the spindle is so the rebuilder can test as an assembly, both for noise and balance/vibration checks.

Milland - thanks - good point.

Since that post I found the folks doing current harig tech support, and they tell me it's not that difficult to swap the bearings. Just by the sound, it seems clear it was the bearings and not the motor. (If I make the repair and the noise is that still there, I'll be wondering about the motor.)

Since you asked, it looks like this:


The drawing and tech support confirm it's an original harig spindle, and it will have 2 front and 1 rear bearing, all inside the silver sleeve to the right (which mounts to a bore in the carrier that is used to elevate the head) - the motor hangs off the back - which is why you need to support it when removing this from the machine.

The motor bearing are cheap and as long as you have it out send to the rebuild shop. They can also run in the new spindle bearing with it. Might cost a bit more for freight but worth it in the long run.

It maybe a solid shaft and you have no choice.

Edit: I found this manual and that spindle is a direct drive spindle. so it is a solid shaft and the motor is part of the spindle. Says it has #7 bearings. Also note it describes handscraping of it's ways for accuracy and not just oil pockets :-) http://vintagemachinery.org/pubs/2804/4247.pdf Thanks to Vintage machinery. I donate to them to keep their service available to all of us. If it helps you, please give them something. :-)

The motor has a simple flex drive to the spindle, check the rubber flex cross, cheap to replace, if there is any wear on the Aluminum drivers replace the assembly.

When reassembling the motor to spindle you need to leave the set screw on the motor side of the coupling barely snug. the reason is that you do not want any pressure from the mounting of the motor to push against the spindle side of the coupling. it is tough to measure the spindle and motor shaft protrusion dimensions and come up with a bit of clearance needed.
Look through the hole in the spindle housing, a thin balded screwdriver, side the half of the coupling apart, then tighten the motor coupling set screw.

You might want to inspect the spindle shaft carefully with the coupling off, There is a sharp end to the keyway, and one of my spindles cracked all the way to the double bearings. I assumed a crash sometime with a PO. Lucky for me I picked up another spindle and motor for cheap.

You can do the bearings yourself, just need clean area, clean tools, clean parts.

@Toms Wheels - was there some particular preload to set, or particular torque to use, when putting the bearing retainer back on? Or do you just put back together, being sure not to bind the coupler, and tighten normally?

What sort of run-in would be used? Can't really vary the speed, does one just run it unloaded for some period?

I have all 3 spindle bearings and the coupling spider coming, will inspect the shaft itself with care.

@Richard King - since I started this thread I found docs and talked to a guy doing tech support for this machine - it's 3 bearings on the spindle, which is held in a collar, motor bolts to the back of the collar. (But new bearings for the motor, or a new motor, are options going forward if needed.) Not sure where 7 bearings would be, unless for some reason there are 4 in the motor?

The motor on mine is a double-wound two-speed, which the tech support guy said they can't easily get anymore, but swapping in a one speed motor would be easy (if needed) and I never ever use the slow speed. (Apparently nobody else did either!)

This is one of those tasks where you pick up lots of facts (read various posts found by a search here, reread the manual and suddenly understand part of it, etc.) - every little bit of data somebody passes on helps lots.

#7 is the tolerance or class of bearing or smallest amount of run-out. The higher the number on a Angular contact ball bearing the better. A # 3 or 5 are less then a 7 or a 9 which we see in Super Precision measuring machines. On the side of races you will see a * or a small o and that is where the bearing runs out the most when measured with a dial indicator. That will be mounted 180 degrees from the highest run out of the spindle.

I hope you ordered # 7 bearings and not # 3. 3's are usually seen on car axels.

I misread your post to mean 7 bearings, rather than class 7. I ordered a standard pkg from the tech support folks, but given the price I suspect they're more class 7 than class 3.

(A little googling about suggests they will be ABEC 7....)

bryan_machine said:

I misread your post to mean 7 bearings, rather than class 7. I ordered a standard pkg from the tech support folks, but given the price I suspect they're more class 7 than class 3.

(A little googling about suggests they will be ABEC 7....)

Click to expand...

The "proper channel" tech support, yeah, should be safe.

We had a thread on PM a year or three back where someone was all superior as to getting "ABEC 9 bearings" cheaply....from a supplier for... skateboards?

Turned out some opportunist was selling "ABEC 9 Bearings" all right.

"ABEC 9 Bearings" were not the product grade, however.

It was the business name of the COMPANY!

The preload is from the Belvelle washers, IIRC. Just tighten the spindle nut until it bottoms, done.

If you want I have a single speed 3ph from my Harig, 1hp. These are Grinder duty motors, No vents, Better balancing very quiet.

First class 7 bearings, (the front set counts the most, DULs)

The motor was factory balanced as an assembly with the the spindle attached.
When the two are pulled apart mark the alignment of the motor and coupler and mating coupler and spindle so that everything goes back in the same orient.
To mark these and not get messed up you have to pull the motor straight and be careful not to let either side rotate.
The preload that really counts is built into the front pair which is trapped by the front collar.
The rear single has wave washers which hold the spindle in a rearward direction as it is supposed to float or slide to make up for thermal growth.
One reason these spindles do not like slot grinding on the back side of the wheel.

A rebuild can most certainly be done in most cases at home if you are used to working with precision bearings.
Since it just now making noise it is doubtful that you have spun a race which is a much bigger deal.

Bob