Harig 6x12 Spindle

928gene928 · Sep 10, 2009

What is the best way to check and or adjust a harig 6x12 spindle? Have notice that the quility of my surface grinding isn't the best (mostly mild steel), has a slight ripple type surface under magnification. Have tried various wheels etc., and it does not feel like there is a loose bearing. Have not used an indicator as yet to check the endplay. Usually allow the spindle to run for awhile prior to grinding, after use the spindle doesn't develop much heat, but have not measured the temp. as yet. I did notice that the coupling between the motor and spindle isn't what I would call super tight, the rubber spider between the two coupling halves has been replaced.

donie · Sep 14, 2009

I cant find my Harig manual, but, there is a test where as an indicator is placed on the face of the spindle, the spindle pressed in by hand to compress the bearing load washers and the spindle should return to zero on the indicator.
If the bearings make any noise at all, or cause heat, they may be done, as they are under light preload. When bearings are new, they cause little or no heat, and make little or no noise.
The correct rubber spider is available from Harig, however, Harig cautions to be sure to index the spindle/ motor connection as it was, it was balanced as a unit they say.

928gene928 · Sep 14, 2009

Harig Spindle

Donie,
Thanks for the response. I need to take the time to measure the end play, and as you mentioned the rebound. In addition I also need to run the spindle for awhile and use my infa-red to check for the temperature before and after. I can't find my manual for the machine, but I'm sure there is some method to check the spindle.

donie · Sep 14, 2009

There should be no shake at all in the bearings. The test of pushing the spindle in and checking the return, only determines if there is some sticking of the bearings. This is needed for thermal expansion. The spring washers that control the preload also allow for expansion.
If its sticky, this indicates some galling, or goo in the spindle housing, and or damaged preload washers. The factory fix is to send the complete spindle and motor in for rebuild.
I, ended up doing the repair myself, with good results, being not up to paying for the factory repair,
Just another thought, I never grind anything as crappy as mild steel, if its bad on hardened steel also, and the wheels and dressing is all good, you may need new bearings.

CarbideBob · Sep 14, 2009

The wheel is pulled outward (towards front of machine) then allowed to return to check for loss of preload. Simple test that tells you nothing aboiut bearing condition, just tests the preload springs. Holding a long screwdriver on the housing with you ear against it will tell you much more abouit the bearings.

Slop in the spider is normal, without some you will have problems.

Sounds like a bearing problem, not a job for the faint hearted although with enough care you can do it yourself. I'm guessing you don't want to drop the $1500 to $3000 a real spindle rebuilder will charge.

If you are not familiar with spindle rework I'll give you a 80% chance of ending up better than you are now. This is a pretty simple spindle. Bearings will not be cheap.
Bob

donie · Sep 14, 2009

Thanks for that CB, I thought I may have that backwards.
The replacement drive spider, that I got from Harig was a bit softer then off the shelf ones, and fit with no slop.
Well, replacing spindle bearings, that is a whole different story. Barden has a pretty good vid of the procedure, and the tools needed.

928gene928 · Sep 15, 2009

Harig Spindle

Thanks to all for your input. I will do all the things you suggest. The machine has been well cared for but is many years old, I suspect that it may be ready for a new set of bearings.

tdmidget · Sep 15, 2009

Before you go spending bunches of money and time on bearings and such check the
alignment of the motor and spindle. While this Lovejoy type coupling will stand a lot of misalignment in most applications this is a different case. Runout between the shafts can transmit a cyclic effect to your wheel.

CarbideBob · Sep 15, 2009

tdmidget said:
Before you go spending bunches of money and time on bearings and such check the
alignment of the motor and spindle. While this Lovejoy type coupling will stand a lot of misalignment in most applications this is a different case. Runout between the shafts can transmit a cyclic effect to your wheel.

Kinda hard to screw up the alignment on a Harig 6x12.
Not much you could do to check or correct it either. :confused:

Bob

precisionworks · Sep 23, 2009

check the
alignment of the motor and spindle.

While there may not be much that can be corrected, it takes only a tiny misalignment to make a Lovejoy work poorly & cause vibration. The typical allowance is only .050" for parallel & axial alignment, and 2 degrees for angular alignment.

http://www.lovejoy-inc.com/uploaded...s/JawIn-Shear6PinInstallationInstructions.pdf

------------
Barry Milton

928gene928 · Sep 23, 2009

Lovejoy Coupling

Barry,
The Lovejoy coupling is the only area I haven't really taken a hard look at so far. Thanks for the information, I have printed up the specifications and will check the coupling out. I have checked the bare spindle for runout and replaced the entire wheel adapter with a new one I had in stock. Not much left? I also did listen to the spindle bearings and they are quiet, not much of a temperature rise after an hour of static running, about 10 degrees.

CarbideBob · Sep 24, 2009

If you really want to check the coupling you must remove the spindle from the machine. It is possible that the coupling has come loose but very, very unlikely.
It is almost impossible to check the alignment, and if it was off by more than .005 I'd be really surprised given the construction of these spindles.
Mark the spindle nose position and carefully remove the motor marking it's orientation as it comes out. This is important, as noted that the spindle/motor is balanced as an assembly. Check the motor bearings for slop when it is off.

When putting the spindle back in it must be realigned to the table ways. This is done by tweaking the three screws in the spindle mount nose.

I would be very sure that I don't have some other problem before doing this, getting the spindle aligned within a tenth is not an easy task if you have never done it.
Bob

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