Myford Speed 10 Headstock Damage Control

Not sure if this is the best forum for this...

The following incident has damaged my beloved Myford Speed 10. While carefully parting off a piece of round and well-oiled 1/2" stainless that was mounted in my Bison 3 jaw chuck there was a sudden loud snap. It happened quickly of course and damaged the work. After shutting down and removing the work, I examined my parting tool and holder and detected no damage. I next examined the chuck which initially seemed to be OK.

However, when I switched on the lathe I immediately noticed a substantial runout on the chuck. I removed the chuck and clocked the spindle behind the threads next to the headstock and was horrified to find that the spindle runout was now .003. Runout had been .0015 at the face of the chuck. Something is definitely amiss. Has anyone experienced a similar tragedy with an ML series machine??? Any suggestions where to start corrective action? Thanks Team.

If the spindle IS bent then you'll need a new one. However, I can't see how a Speed 10 would be capable of producing enough torque to do that kind of damage unless you were trying to part-off miles from the chuck whilst in the lowest back gear.

How does the spindle feel when rotated by hand, is it notchy, which might indicate a bent shaft or perhaps a broken-up taper roller bearing?

Martin.

Thank you.

I was parting off about 1/4" from the chuck jaws in low back gear with the parting tool projecting about 1" from the rear holder. The spindle turns smoothly and freely. I checked for unusual noises with my stethoscope. Everything sounded normal. When I bought the lathe about 3 years ago, I checked the spindle for end play and slap. However (shamefully), I did not check the spindle lock nut on the outer end of the spindle. I started to remove the spindle to check the bearings and in the process I noticed that the previous owner had installed the lock nut far tighter than the instruction manual specifies. At any rate, my present intention is to check and/or replace the bearings. A friend who is a retired machinist has a home shop. I will ask him if he can check out the spindle. Although I am also concerned about the headstock casting around the tapered bearing housings, there are no visible cracks in the casting. Hopefully everything is repairable.

It might be worth checking the teeth on the back gear as you may have chipped one out! You have stated you were in back gear low range, lots of torque there.

Clive

when i had my ML10 it was at least 3 months before i realised that the headstock holding bolts were actually loose. i discovered this one day when trying to drill something with the drill in the tailstock and pushing into the chuck held part, the actual headstock casting slid backwards against the force of the drill in the tailstock being pushed forward. I then had to take the time to retighten the bolts holding the headstock in place and hope that they were tightened correctly and with enough torque .

could this perhaps be something to do with your problem? one of the headstock holding clamps being loose allowing the headstock to twist a little, giving you an increased runout ?

something to check maybe

Z

The headstock is now dismantled. The spindle appears to be in very good condition. However, I will still have my machinist friend thoroughly check it out. After removing the bearings from the spindle, I pushed each into their raceway and turned them by hand. The gear end bearing appeared to move freely while the chuck end bearing seemed to have a rough spot in its rotation. I will be replacing both. Both bearing raceways are less than favorable. The bubbly things shown at "A" in the photos below are a puzzlement. I could not see these through a 10X lens. However, when I took the photo I used a Marumi variable neutral density filter on my 50 mm macro lens. The filter was set somewhere between ND 4 and ND 6. The added contrast from the filter sure made these things stand out. I would welcome any suggestions as to what these are. The smearing(?) and scoring I believe can be attributed to too much torque applied to the lock nut by the previous owner. It may also be the result of a heavy handed knurling technique. I had to use an extension on the 1 1/2 " tommy bar (mild steel bolt) that I used to remove the lock nut. It had to be forcefully backed off for the entire length of the thread resulting in a bent tommy bar. I believe the lock nut threads were stretched by excessive torque. After mounting the spindle in a padded vice, I used the tommy bar to thread the lock nut on and off several dozen times until it moved freely with moderate finger pressure.

Gray

Thank you. In your opinion, would replacing the prescribed bearings with sealed bearings result in any appreciable advantage or disadvantage?

Bill

It might make sense to set your spindle between centres and check the runout before you fit new bearings and start to reassemble.

I would replace the bearings with like for like if the spindle proves to be OK.

Martin.

Just back from my semi-retired friend's home machine shop. He mounted my spindle in his lathe and the runout was less than .001. Whew!! I saved significant coin of the realm there. I fully agree with the words of wisdom from Martin and Gray. I will order the bearings in accordance with the Myford specification. Time to fabricate a race way removal tool..... Now where did I leave my spectacles? (They say as you grow older the mind is the second thing to go. I wonder what they mean by that.)