Twin MillDrill Overheating.

This topic has 24 replies, 9 voices, and was last updated 30 March 2021 at 18:08 by Dave Halford.

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25 February 2021 at 22:03 #530162
James Frankland
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@jamesfrankland41848
Hi All

I havent posted an update for a while, but if anyone can shed any light on this id be really grateful. Hope this is in the right place for this sort of question?

I have an old TWIN MillDrill. Its been great for years and is trammed up lovely. When I bought it, the guy said the quill heated up "a bit". It always has but seemed to be ok. However, now it heats up a lot. I know it probably needs lubricating, but i cant see for the life of me where to get oilgrease to the main bearing. Ive tried everything. Believe me. I thought it might also be that the bearing is cramped too tight, but loosening things off for an experiment doesnt make any difference.

Im thinking that the bearing is shot and needs replacing. I did take the whole head off a while ago and couldnt get the bearing out, but to be fair i didnt make that much effort.

Ive never seen a machine like this anywhere, not even on the internet (only lathes.co.uk).

Its such a good machine i really need to sort it out.

See pics.

Any helpadvicetips much appreciated.

Thanks

James

Edited By James Frankland on 25/02/2021 22:04:21
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25 February 2021 at 22:03 #28007
James Frankland
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@jamesfrankland41848
Could do with a hand if anyone can help?
25 February 2021 at 22:16 #530165
Emgee
Participant
@emgee
Hi James

Are there any screws in the quill casting that don't seem to do anything ? if there are screws removing may reveal an oiling point.

Or it's likely the bearings were grease filled on assembly and the grease has now migrated from the bearing surfaces, cure is dismantle and re-grease.

Strong and useful looking machine.

Emgee
25 February 2021 at 22:49 #530177
not done it yet
Participant
@notdoneityet
It may be a sealed bearing? If so, there would not be any lube point. Bearing is likely past its best and needs replacing.
26 February 2021 at 17:27 #530348
James Frankland
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@jamesfrankland41848
Thanks guys. I suspect your correct. I did take it apart once so i could see the bearing but couldnt get it out. I think its sealed. I'll take it to bits tomorrow and have a look at getting the bearing out somehow.

I seem to remember I couldnt get the pulley off the top which needed to come off. Anyway, will investigate more tomorrow.
26 February 2021 at 17:50 #530357
Dave Halford
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@davehalford22513
Lathes says taper rollers, you may need to drive or push the spindle out. There will probably be spacers and or preload nuts of some kind to remove first.

Use a gear puller on the pulley carefully they are sometimes fragile or bendable
26 February 2021 at 18:06 #530366
john fletcher 1
Participant
@johnfletcher1
I have a Naerok drill / mill ( made in Korea and is Korean in reverse), the spindle pulley is on a taper, it needs warming up to expand before it will release off the taper. I used a hot air gun for maybe ten minutes, then very carefully used a three leg puller. The so called Chinese crap by some, is light years better than my Naerok drill / mill, I'm never the less happy with what I have got. John
26 February 2021 at 18:28 #530369
Brian Morehen
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@brianmorehen85290
A great friend of mine no longer with us . I well remember him saying a man must have put it together we just have to get it in bits to repair it.

Good luck Bee M
26 February 2021 at 18:57 #530387
Steviegtr
Participant
@steviegtr
As said above check for grub screws / holding bolts etc. Also the possibility of circlips.

Steve.
7 March 2021 at 20:29 #532412
James Frankland
Participant
@jamesfrankland41848
Hi All,

Thanks for the comments. I took it apart but still have to get the bearings out. I did a video which you can see here. https://www.youtube.com/watch?v=pBVsZYpL7u0

Anyone have any ideas how to get the bearings out? There is a sleeve at the top that seems pressed or tapered on. That must have to come off.

Thanks all.

Regards

James
7 March 2021 at 21:02 #532429
Dave Halford
Participant
@davehalford22513
Might be like a car rear half shaft bearing – a pressed on retaining ring, If the hole doesn't have a grubscrew in it
7 March 2021 at 21:04 #532430
Emgee
Participant
@emgee
James

Perhaps the hole is for a C spanner to remove the nut, take care though it may just be a locking nut to retain the main nut and pre-load, the spindle will then perhaps pass down through both the top and bottom bearings. If the bottom bearing is a tapered roller bearing the inner will no doubt be shrunk fit onto the spindle.

Emgee
7 March 2021 at 21:04 #532431
James Frankland
Participant
@jamesfrankland41848
That ring at the top of the bearing, the thing that i said needs to come off did have a single, small grub screw in it.

??
7 March 2021 at 21:11 #532436
noel shelley
Participant
@noelshelley55608
If you can see the bearing and it's sealed, you may be able to pop the seal out with a very small screwdriver, re grease it and pop the seal back in. Worth a try ? Noel
8 March 2021 at 12:32 #532551
James Frankland
Participant
@jamesfrankland41848
Hi Noel

That was my initial thought, to re-pack the bearing, but its a metal cased bearing and ive already buckled it trying to lever off what i thought was a rubber seal. Not that it matters, its got to come off….
8 March 2021 at 12:47 #532553
Ian P
Participant
@ianp
Posted by James Frankland on 07/03/2021 21:04:36:

That ring at the top of the bearing, the thing that i said needs to come off did have a single, small grub screw in it.

??

Its possible that there is a brass pad under the grubscrew as the ring/collar may actually be a nut that sets the bearing preload. If it is a nut then the grubscrew hole may double as a recess for a peg/C spanner. I would look very closely (magnifying glass) where the shaft emerges from the nut/collar.

Ian P
8 March 2021 at 14:41 #532585
Dave Halford
Participant
@davehalford22513
Posted by James Frankland on 08/03/2021 12:32:44:

Hi Noel

That was my initial thought, to re-pack the bearing, but its a metal cased bearing and ive already buckled it trying to lever off what i thought was a rubber seal. Not that it matters, its got to come off….

Actually it did matter and no it doesn't have to come off. The shield is an integral part of the bearing pressed on during assembly, you can't get them any other way. The idea is to keep the grease they come with inside the bearing when there is no other way to get fresh grease in there. also known as 'sealed for life bearings'.

You need to get the shaft out of the bearing once the ring is removed then you can decide which bearing is stiff, probably both. Just buy new ones, the number is engraved on the bearing.
8 March 2021 at 18:45 #532625
not done it yet
Participant
@notdoneityet
Re the comment on your vid. The bearing outer race will not be a shrink fit in the casing – it will be a simple press fit.
8 March 2021 at 21:06 #532655
James Frankland
Participant
@jamesfrankland41848
Thank you all. I wanted to go and try a C spanner this evening but ran out of time. I will try tomorrow. Carefully of course.

Ill take some picsvideo.

Thanks again, your adviceopinion is much appreciated.

James
10 March 2021 at 19:34 #533066
James Frankland
Participant
@jamesfrankland41848
Hi All.

Thanks, it was in fact a screw on retainer as several people suggested.

Here is a video of removing the bearing and shells. https://www.youtube.com/watch?v=rHWNePA_ptY

In the video, i dont remove the bottom shell, but that is now out. I just tapped it out using a steel tube that almost fit.

Also, i removed the bearing race from around the spindle by heating the bearing and it slid over the cold spindle.

Only problem is that the bearings seem perfectly ok. However, i think that they may have been stiff. Then i pumped in so much grease that i might have made it worse by completely filling the quill chamber with grease. Maybe?

Anyway, whatever, im going to replace the bearings of course.
Thanks again.

James
10 March 2021 at 19:54 #533069
Emgee
Participant
@emgee
James

Looks like a well designed spindle but may have been stiff if there was too much pre-load put on the bearings by the retaining nut, and as you say the grease around the spindle would cause drag.

Emgee
11 March 2021 at 11:36 #533184
James Frankland
Participant
@jamesfrankland41848
Hi,

Anyone got any good suggestions of where to get some good quality bearings from. Lots of places around, but i want something thats reliable and quality.

Thanks

James
11 March 2021 at 13:00 #533214
Dave Halford
Participant
@davehalford22513
Somewhere that sells primally bearings to the trade, get the seals at the same time. You don't want mild steel ones from the ROC.
30 March 2021 at 16:26 #537109
James Frankland
Participant
@jamesfrankland41848
Hi All

I have the new bearings for the mill. I am going to assemble it one evening this week. I will do a video.

Just one final question i hope. The threaded ring that I took of is providing the pre load on the bearing. It just screws on and there is a grub screw that goes onto the threads which seems a bit odd. Anyway, as I was able to get it off fairly easily with the drill handle, It wasnt that tight.

So my question is, how do I know how tight to do it up? just finger tight?

The bearings were overheating, so it was either damaged bearings, too tight or all the grease i put in.

So i need to make sure i do it up correctly.

Any tips? This is the previous video and you can see it. I'll do another this week.

Thanks all.

James
30 March 2021 at 18:08 #537137
Dave Halford
Participant
@davehalford22513
James,

If it was me I'd go finger tight and check the play in the spindle etc until the play goes rotating the spindle at the same time.

Don't go as tight as it was or you will have to tap it out again. Hopefully your arm will remember how hard it worked before to undo it

Tighten the grub screw when happy.

There was probably a factory spec somewhere that involved string with a weight on one end wrapped round and round the spindle, when the weight stopped moving the preload was correct. If only we knew how heavy it was.
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