Author Topic: Myford Spindle problems (Read 14144 times)

Don1966 · « **on:** July 30, 2015, 12:10:42 AM »

My Myford Super 7 has been giving me hints that it had problems. While cutting of metal with the parting tool the spindle would defect or push it self below the cutter. After taking the headstock spindle out and thrust bearings I found the problem. The two thrust bearings had to much play in them. So I ordered some from the UK. they should be in Monday. After I get them installed I will see if this cures the problem.
I have a few photos of what I am talking about.
The head stock with the spindle, pulley and gear removed.

The two thrust bearings

Don

b.lindsey · « **Reply #1 on:** July 30, 2015, 12:17:23 AM »

I hope the fix will be as simple as replacing the bearings Don. Sure beats what you went through with Grizzly!! Keep us posted.

Bill

Dave Otto · « **Reply #2 on:** July 30, 2015, 01:32:59 AM »

Hi Don

I have been wondering what you have been up to?

These appear to be angular contact bearings? is it possible that they were not shimmed properly? It sure doesn't seem that a ball bearing would wear enough in a home shop to create that much slop.

Curious to see what you find out.

Dave

Stuart · « **Reply #3 on:** July 30, 2015, 07:33:26 AM »

Don

Make sure the middle outer shim has the gap at the top.

Make sure the spindle is well to the right , lock up thr two outer callers on the left.

Just nip up the clamp screw on the spindle adjuster so it can just move then tightn by hand to load up the bearings , tighten the clamp .

Now slack off the LH outer nut , tighten the RH until the spindle just nips up back off one slot , then fully tighten the LH one oil well

Run slowly check temps, build up the speed and keep a look out on the temp.

After a bit of run time test the end float with a dti repeat above if not nearly nil

Don't forget the the outer space need to be locked up before you preload

Yes I have been through it with my cony Myford put a non matched pair in cost me a new set at £170 they are bigger than yours the 7007 series

Take care a jobs a good in if you can still count to ten

Stuart

Graham Meek · « **Reply #4 on:** July 30, 2015, 10:26:04 AM »

Hi Don,

In the free state these bearings do have a lot of play even when new. The play is taken out when they are installed and correctly adjusted. There is a procedure to follow which is described in the Super 7 lathe manual. It is very easy to over tighten these bearings which will lead to premature failure. The play needs to be adjusted out of the bearings with the spindle well forward. This forward movement is achieved with the large castellated nuts. These move the the bearing assembly towards the change gears or away from them as the one nut is tightened and the other slackened.

As the bearing assembly moves this draws the front taper bearing on the mandrel / spindle in and out of the front bronze bearing thereby setting the running clearance. The bearing assembly is moved towards the changewheels as far is it will go until the spindle will no longer revolve, (gentle with the C spanner). The front castellated nut nearest the pulleys is un-screwed a measured 1/4" on the periphery of the nut and the castellated nut nearest the changewheels is locked up. This should provide the correct setting for the taper bearing as set at Myford's.

Do not forget to hold the oil wick down with a darning needle prior to assembly. Access to do this is via the grubscrew at about 8 o'clock when looking at the front of the headstock.

I hope I have not missed anything as it is 30+ years since I last did one of these, and the memory is not that good these days. If you are already aware of this procedure then sorry for trying to tell you something you already know, ( but it may help others in the future).

My best regards
Gray,

Don1966 · « **Reply #5 on:** July 30, 2015, 02:16:43 PM »

Thanks guys for the help. The two bearings are indeed bad, one worst then the other. This problem has been on this lathe since I purchased it. I did the procedure as per the manual many times. What happens is after I preload the bearings and make the V bearing adjustment i still have to much movement back a forth. So when I install a piece between center and pushing with the tailstock the front bearing would seize up. So I had to back off on the adjustments. This would make the spindle to loose. I could push it back and forth by hand.

Don

Stuart · « **Reply #6 on:** July 30, 2015, 02:35:14 PM »

Don sounds like when you did the adjustment the outer races were not lock up solid.
they need to be to set the pre load ( remove any end play )

but if they are bad then nuff said

but please bear it in mind when the new ones are installed

spindle clear of front bearing , outer rear races locked up , adjust the pre load , then move the spindle back with the outer nuts as per the manual

on my big bore i needed a little more front bearing clearance than Gray said but that how mine is you don't want it nipping up at speed else the chuck will unscrew

start a little slack then adjust it as you feel fit

Stuart

Don1966 · « **Reply #7 on:** July 30, 2015, 03:31:24 PM »

Thanks Stuart I do believe that even with the spacer between the bearings that the two inter races were touching and there wasn't any preload left to do. There is that much slack in the bearings

Don

Stuart · « **Reply #8 on:** July 30, 2015, 03:57:09 PM »

Ok Don

Stuart

steamer · « **Reply #9 on:** July 30, 2015, 06:36:40 PM »

They may be angular contact, but not a matched pair, or a Universal grind.

I'd love to see the adjustment procedure from the manual. It would seem silly to not make these bearings a matched pair for DB mounting. Then you wouldn't care about the preload on these as it's ground into them. Tighten the nut till you grunt and you're done.

A cheap and dare I say cheerful solution is to put shims between the two bearings as single bearings are very much cheaper than matched pairs or DU grind.....but it would seem a false economy for a lathe.......to say nothing of a lot of painful work.

Dave

Jo · « **Reply #10 on:** July 30, 2015, 06:40:37 PM »

By special request

Jo

steamer · « **Reply #11 on:** July 30, 2015, 06:45:48 PM »

Oh dear lord. That's going to be a right royal pain....follow the procedure Don.....

Dave

Graham Meek · « **Reply #12 on:** July 30, 2015, 06:47:59 PM »

The presence of the spacer on the Myford is to allow the oil into the bearings as it is more of a "C" shape, (cut-out next to Zerk or oiler). I was going to ask Don if he has tried applying "blue" to the spindle taper and trying this in the bronze bearing to see if there is all round contact. For myself I suspect the bronze bearing may be oval which new bearings will not cure.

My best regards
Gray,

steamer · « **Reply #13 on:** July 30, 2015, 06:51:57 PM »

Quote from: steamer on July 30, 2015, 06:36:40 PM

They may be angular contact, but not a matched pair, or a Universal grind.

I'd love to see the adjustment procedure from the manual. It would seem silly to not make these bearings a matched pair for DB mounting. Then you wouldn't care about the preload on these as it's ground into them. Tighten the nut till you grunt and you're done.

A cheap and dare I say cheerful solution is to put shims between the two bearings as single bearings are very much cheaper than matched pairs or DU grind.....but it would seem a false economy for a lathe.......to say nothing of a lot of painful work.

Dave

What I was getting at above is the DU grind pair is designed to have the inner and outer races touching on their faces. The bearings are made such that when that happens, the balls become preloaded. It' just about impossible to mess these up unless you get them dirty....but that is not the case here....so I would follow the instructions to the letter....as given in the Myford manual. Disappointing......

The up side is the bearings are going to be about $20 a piece, instead of $400-500 a matched pair....still.......

Don1966 · « **Reply #14 on:** July 30, 2015, 07:55:36 PM »

I took the bearing apart and didn't try real hard to pop it apart. The balls are oval shape and you can see the wear in the race. If you look close you can see a ring around the balls. You can also feel the odd shape.
Gray I have another V bushing if it is oval but I slipped the spindle into the bushing without the bearings and it is a good fit. If you tap it , it will lock in place so I would say thats good. The C spacer also helps to load the bearing. By the way the spacer is about .020" thick.
Some more pictures.

Don

Don

Stuart · « **Reply #15 on:** July 30, 2015, 08:04:55 PM »

Don

those balls are "K" for no good

surprised you could not get the bearings localy

Stuart

Graham Meek · « **Reply #16 on:** July 30, 2015, 09:36:28 PM »

Hi Don,

I am glad the bronze bearing is OK, and those bearings have certainly had a hard life.

My best regards
Gray,

Don1966 · « **Reply #17 on:** July 30, 2015, 09:42:38 PM »

Stuart and Gray thank you for your inputs I really appreciate it. I will post once the bearings are install and the spindle tested again.

Don

Don1966 · « **Reply #18 on:** July 31, 2015, 12:05:10 AM »

Attached is a sheet on the Angular thrust bearing for those not formiliar with his type bearing. I think the sheet explains it well.

Don

b.lindsey · « **Reply #19 on:** July 31, 2015, 12:50:21 AM »

Interesting Don...the whole thread has been in fact. Did the bearings arrive today?

Bill

steamer · « **Reply #20 on:** July 31, 2015, 12:55:41 AM »

Quote from: Don1966 on July 31, 2015, 12:05:10 AM

Attached is a sheet on the Angular thrust bearing for those not formiliar with his type bearing. I think the sheet explains it well.

Don

Significant isn't it!? the reason they wear like that is probably because they had TOO LITTLE preload. As a result, the ball slide instead of roll, and that causes wear.

Dave

steamer · « **Reply #21 on:** July 31, 2015, 01:05:18 AM »

The actual amount of preload depends on the bearing size, and it's desired stiffness, and speed.

I just spec'd in some that have a light preload...like 50 newtons...on a much smaller shaft

Dave

steamer · « **Reply #22 on:** July 31, 2015, 01:07:51 AM »

Graham,

If a OD and ID matched pair of spacers were to be used, instead of the OD shim...then a DU pair could have been used, and a hole in the spacers would allow oil to get to the bearings and percolate off just fine.

These are drip feed right?

I'm sure the decision on the bearing was about money.....

Dave

Don1966 · « **Reply #23 on:** July 31, 2015, 01:38:03 AM »

Quote from: b.lindsey on July 31, 2015, 12:50:21 AM

Interesting Don...the whole thread has been in fact. Did the bearings arrive today?

Bill

No Bill not before Monday at least that's the expected delivery date.

Dave there is no lubricator just a flip cap spout to add oil to.

Don

Graham Meek · « **Reply #24 on:** July 31, 2015, 10:13:03 AM »

Hi Dave,

If I were designing the bearing at the back of this particular lathe I would go for a back to back matched pair sealed for life, with a good sealing arrangement to keep out debris, etc. The reason being there is less chance of the bearing being overloaded as is the case at the moment.

I think some time back I advised Stuart to put a shim between inner and outer races on his lathe for this reason. Most of the un-matched angular contact bearings these days that I have come across will work back to back. With the required pre-load being taken care of during manufacture. I currently have two unmatched 7002 C bearings in my FB 2 quill which have no shim and have been running like this for 20 years with zero end float. (There are a couple of dots on the bearings that it is recommended be aligned in a back to back configuration)

Myford use a grease gun, but filled with oil, (always a topic of complaint). This is used to inject oil into the bearing and this is why the spacer is "C" shaped. Without this entry point the oil would go nowhere as the Zerk / oiler is directly above the bearings interface. This spacer also allows for the end wise movement of the spindle to adjust the front bearing. Always ensuring there is a path for the oil from the Zerk to get the bearings. We have to remember we are dealing with a lathe that was designed about 60 years ago and attitudes towards sealed for life bearings was frowned upon. This bearing assembly, assembled with grease would last for years without any need for attention. The average owner at that time would have probably turned around and drilled a hole to ensure extra lubricant could be injected, such were the views at that time.

My best regards
Gray,

Stuart · « **Reply #25 on:** July 31, 2015, 10:30:12 AM »

Yes Gray it has a shim fitted as you commented and locked up ,no if buts or maybes

As to that oil pot I would put a grease nipple in should be 2BA but yours may be different

The Myford oil gun ohh dear , I have bought a plastic oil gun for Myford , not from Myford but a Myford lathes spare site cheap as chips does not leak and is fitted with a o ring to seal better about twenty quid

Stuart

steamer · « **Reply #26 on:** July 31, 2015, 10:46:40 AM »

All excellent points Gray. Grease pack would be best as this spindle doesn't turn very fast. You could still have the end float adjustment......

Graham Meek · « **Reply #27 on:** July 31, 2015, 12:10:59 PM »

Not wanting to move off topic, but still pertinent to the Myford. I had supplied with my Emco FB 2 an all metal grease gun manufactured by Hallbauer in Germany. It is a series F with a pointed nozzle and this lasted for 20+ years as an oil gun. When it decided to give up the ghost recently I was preparing myself for a costly replacement. I found the exact same model being supplied for a chainsaw, at £7, (UK Pound Sterling), including postage I could not believe my luck. Even the tip matched the old Emco, but looking at the Hallbauer site there is a Myford "all purpose" type available. (The same gun supplied with the lathe 30 years ago is still going strong used as a grease gun).

My best regards
Gray,

Don1966 · « **Reply #28 on:** July 31, 2015, 10:08:34 PM »

Gray I appreciate all of your wisdom and thank you very much for even looking in. The bearings arrived today and I am a happy camper

. The thrust I measured using the tail stock to push with was less than .003" so I am happy with that. After it every thing beds in I we'll see if I can do a little better.
Thanks all for the support.

Don

Stuart · « **Reply #29 on:** August 01, 2015, 07:18:18 AM »

Don

Be care full using the tail stock to push for measurement it may/will be bed flex
Better to put the indicator on the bed near the HS and applie hand pressure

For example put the indicator on the bed indicating the front of the spindle then push away from you on the HS casting it will show a movement

Great work glad you have it sorted now enjoy it

Stuart

Graham Meek · « **Reply #30 on:** August 01, 2015, 09:31:51 AM »

Hi Don,

I am glad that you have your lathe back together and that my few words have been of help. I would definitely go along with what Stuart has said about the method of checking.

The best sure-fire way with these bearings is to have two individual matching spacers between the inner and outer races. This way the bearings are pre-loaded to the manufacturers recommendations. With an added advantage that the bearings are all locked up solid, with no independent moment between one race and the other. Most good bearing factors can supply these shims in various diameters / thickness's.

Sorry for being an infrequent visitor but my projects and writing get the better of me, it is this that keeps me away.

My best regards
Gray,

Don1966 · « **Reply #31 on:** August 04, 2015, 06:40:06 PM »

Gray I am glad you did check in, because you were correct about the spindle bushing. It was indeed oval shape and replacing the bushing improved my read out dramatically. I no long have high reading moving my Chuck up and down less then .002" TRO. I get a better reading with my chucks and collets. The run out on the collet is less the .00025". My four jaw Chuck has less then .0015" TRO. My new adjustable backplate gives me a lot better runout after adjusting the Chuck. I can get the TRO to nothing.

This is my arrangement to pull the bushing I had things on hand to do it with.

Install the bushing and I had to remove it again because the oil hole didn't quiet line up, but nailed it on the second attempt.

Finally my lathe is more precision now after changing both the rear and front bearings. I appreciate all of your inputs in resolving this matter. I had put it off far to long and could kick myself for not doing it sooner.

Don

Tennessee Whiskey · « **Reply #32 on:** August 04, 2015, 07:07:53 PM »

Ain't nothing a Coonass can't whoop or fix

my brother

Cletus

Graham Meek · « **Reply #33 on:** August 04, 2015, 10:28:10 PM »

Hi Don,

I was suspicious of the front bearing especially when I saw the condition of the angular contacts you replaced. The use of "micrometer blue" medium will show exactly where the spindle is or is not touching, but you have it sorted now. I would not be worried about those measurements, a static spindle is one thing, a dynamic spindle with a film of oil around is quite another.

My best regards
Gray,

Bjorn_B · « **Reply #34 on:** August 27, 2015, 08:09:58 PM »

Excellent! Did the front bearing reqire any scraping?

Don1966 · « **Reply #35 on:** August 27, 2015, 11:52:32 PM »

Quote from: Bjorn_P on August 27, 2015, 08:09:58 PM

Excellent! Did the front bearing reqire any scraping?

The bearing was purchased from Myford and fit was great so no scraping. Thanks for looking in.

Don

b.lindsey · « **Reply #36 on:** August 28, 2015, 12:53:00 AM »

You should be good for another 50 years+ now Don and you have to feel more confident about the Myford's precision now too...nicely done!!

Bill

Don1966 · « **Reply #37 on:** August 28, 2015, 02:20:44 AM »

Quote from: b.lindsey on August 28, 2015, 12:53:00 AM

You should be good for another 50 years+ now Don and you have to feel more confident about the Myford's precision now too...nicely done!!

Bill

Thanks Bill and yes I can see the difference when cutting and parting off.

Don

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Author Topic: Myford Spindle problems (Read 14144 times)