Thread: MT5 adapter wearing out.

After what handlebar Phil found in his headstock (and i'm sure many others have too) you should really pull it down, clean out the casting sand, check the bearings for damage, spindle for straight etc then reassemble if all is well. The big question is will this void warranty?
Can you test how far the adapter goes in at different points? No wait, that would only show up if both the bore and adapter are oval.
Am i right in thinking that ALL mt5 things you have come loose, not just the adapter?

Originally Posted by Ueee

After what handlebar Phil found in his headstock (and i'm sure many others have too) you should really pull it down, clean out the casting sand, check the bearings for damage, spindle for straight etc then reassemble if all is well.

I'll second that....or is that third???

(handlebar) Phil

Originally Posted by Ueee

you should really pull it down, clean out the casting sand, check the bearings for damage,

Hi Ewan,
I'm pretty sure he has done that already.
I think it might time for some very careful measuring.
Maybe one of the bearings isnt seated properly?(and maybe thats wishful thinking?)

Stuart

I bought a small live centre with a 2MT and a 3 to 2 MT sleeve for it, the live centre with the 2MT doesn't have a tang so the sleeve was going to live on it and I smacked it on with a small copper hammer, I put the hammer on back on the hook and was heading towards the lathe and the sleeve came loose in my hand ???

So I ""SMACKED"" it on again, I give it a wiggle and it came off !!!!

So I grabbed the old one out of the draw and same thing, anyway I had to get on with it so I SMACKED SMACKED SMACKED SMACKED it on and it just slid orrfffff AGAIN

So I just slid it in by hand and stuck it in the tail stock and did the job, I finished the job which was only about 5 minutes if that to turn 1.5 mm off a couple of plastic rollers so there wasn't much pressure on it, anyway I thought of this thread and was going to blue up the bits to see whats
going on, but I couldn't get the sleeve back off even with a crack with the copper hammer to side ?

Weird things tapers ?

See smacking does not work. The do gooders have been telling you that for years and now you believe it. You know there is a reason for what you have described?

Dean

Well Dean I was sure a left hook and right upper cut would have done the trick, nup.

What's the good reason a why good smack don't work ?

I don't know but it happened so there would be a reason why LOL.

Dean

The only thing I can add is one time I had a cheap MT3 chuck that would constantly come loose after backing off . In the end I tracked it down to the small end being too big and it never locked up enough at the large end . So when the drilling load came on it shook about at the large end enough to work loose and popped out after backing off .
Maybe the MT5 is doing the same thing locking up at the small end only .
Morse tapers are so slight that they usually lock up real easy .
I think you need to establish that the two taper surfaces are accurate tapers .

Originally Posted by Bryan

It would still be good to have an understanding of what's really going on before a claim. I think I would be trying to test the spindle geometry. Not sure how yet.

Edit: To be clearer, I would be trying to find out if the spindle overall is (a) straight and (b) round, especially in the bore.

I have no idea about the possible effects of bad bearing seats. Maybe you could run some tests with and without preload?

looking into it Bryan, though without the means of checking it myself, the quotes are way more than expected.
seriously considering using a fine lapping compound, and constantly switching between the testbar and adapter when lapping so both mate with the spindle.

when preload is increased the adapter or MT5 test bar come loose quicker.
had not checked it without preload

Originally Posted by Ueee

After what handlebar Phil found in his headstock (and i'm sure many others have too) you should really pull it down, clean out the casting sand, check the bearings for damage, spindle for straight etc then reassemble if all is well. The big question is will this void warranty?
Can you test how far the adapter goes in at different points? No wait, that would only show up if both the bore and adapter are oval.
Am i right in thinking that ALL mt5 things you have come loose, not just the adapter?

gearbox was stripped cleaned and painted.
both the adapter and MT5 test bar come loose.

Hi Lather,
Did you use anything with an MT5 taper before you replaced the bearings?
Stuart

Originally Posted by Stustoys

Hi Lather,
Did you use anything with an MT5 taper before you replaced the bearings?
Stuart

The test bar was loosening up prior to replacing the bearings.
assumed the test bar or spindle was not ground properly.

had not known about the adapter until getting the lathe running, and test machining between centers.
still at the stage of setting the lathe up due to sorting out other problems.

After reading about the issue so far, are you sure that the taper is MT5? I ask because MT5 has a taper of 0.63151"/ft, a Jarno taper is 0.600 "/ft. If only one part is hanging in there it sounds more like the wrong taper. (My lathe has a Jarno taper in the H/S)
Can you make a casting or something so that you have a part to measure?

Michael

Have you allready measured the bore with calipers to confirm that your sleeve/test bar actually fits over the total length of the ground taper in the bore.

Have you confirmed that the length of the ground spindle taper is the same length or longer than your sleeve/test bar.

Are you still trying to confirm if your pre load on the bearings is having an effect on your bore.

Have you measured the wall thickness of your spindle to see if it is feasable that tightening your bearings would be capable of distorting your spindle bore.

The test bar should be accurate. I would suggest that you do nothing to affect the spindle such as lapping until you find out what is happenning for sure. If you do that will surely effect any future claim. As this is a new lathe

spindle and adapter were cleaned, did not have this problem on my previous lathe.
the lathe is new and similar to an al 540, using the adapter supplied with the machine.
The problem gets worse when applying more preload to the taper bearings, and turning the spindle by hand causes the adapter to eject.

I would suggest that you at least ask the question of the supplier. No mention of this in your posts. Is there a reason for not having it fixed under warranty?

Dean