MT5 adapter wearing out.

[lather]

attached a pic which shows wear and tear forming on the rear of the MT5 adapter, as well as the spindle taper.
whats odd is that when either using the adapter or MT5 test bar, it loosens up quickly when running the lathe, even if lightly banging it in, which takes some effort to get out when the lathe has not been run.
at first it looks like rust, best guess is that when the cast iron MT5 adapter wears it forms a type of copper color dust.
seems to be traveling further up the adapter the longer it's used and can't decide if either using lapping compound, or wrapping 1200 sand paper around the adapter and spinning it in the spindle would sort it out.

Is it possible that the taper bearings are transferring an out of round bore or (misaligned bores) back through to the spindle taper causing an egging of the spindle ? as neither quick fix would solve the problem

[Stustoys]

Hi

Did you clean it very well?
Have you blued the taper to see if its seating correctly?

Stuart

[Bryan]

What's the machine? Are you sure the spindle taper is MT5? Because that adaptor appears to have no wear except on the end. Blue will reveal all.

[lather]

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.

Had blued both the adapter and MT5 test bar.
looked like a small section of the rear when blued is not making contact, trying to determine if it's due to the taper not being ground correctly, or caused by uneven bores.
what's strange and makes me assume it's the uneven bore being transferred from the taper bearings is that when lightly giving it a tap in the spindle it takes a good hit, using 35mm wood rod to get it out the spindle when the lathe has not been run.
repeating this and only running the lathe on 45 rpm, it quickly loosens up.

[shedhappens]

Lather have you fitted your test bar and checked it with an indicator ? what did that tell you ?

maybe even test while you adjust the preload ?

This would be the first time I have heard of a spindle bending under preload, unless the spindle was damaged/bent sometime previously and the preload is trying to pull it straight ?

[lather]

the readings using a test bar were not consistent.
runout is around 0.01mm, though there are inconsistent jumps of +/ - 0.01.
test bar has to be constantly reinserted as it kept coming loose.

[Stustoys]

spindle and adapter were cleaned
Figured it would have been but I had to ask.



looked like a small section of the rear when blued is not making contact, trying to determine if it's due to the taper not being ground correctly, or caused by uneven bores.

Are you sure you are reading the blue correctly?
If the rear isnt making contact how can it be getting wear and tear?
Though we are rapidly heading out of my depth and I've run out of simple ideas.

Stuart

[RayG]

Hi Lather,

Just a dumb idea, is it possible that it's a little bit oval shaped, so that it appears to seat and blue ok, but when it rotates a little it come loose.

Other than that... no idea?

Regards
Ray

[lather]

Stuart, most of the rear surface is making contact, though there was a small patch that seemed to have more blue due to there being less contact, though overall it looked as if 90% of the surface had contact.

[lather]

Ray,
the spindle itself could be oval, and difficult to measure due to inconsistent jumps,
the reason i asked if it was possible for an egged bore to transfer it through to the spindle taper is that it's happening on the rear of the adapter, were the taper bearing sits on a thinner part of the spindle, the front part of the taper is on the more solid spindle flange.

[steran50]

HI:),
I certainly wouldn't be using Sandpaper in the Spindle. It certainly sounds like that You have some sort of Problem with the Spindle. The Lathe should have a Warranty so let the Supplier sort it out. Personally I have a Hafco AL-960b Lathe, I have used the Supplied MT5 Adapter with a MT3 Test Bar and I have used a MT5 Test Bar straight into the Spindle with No Problems either way - My Spindle Runout is Consistant.

[shedhappens]

something has to be flexing the shaft if the tapers pop out when you turn the spindle, maybe one of the gears has not been machined properly and is not concentric to its shaft ????

can you check that one of the gears is not meshing against a gear on the spindle too tightly at some point of rotation,

I know it sounds far fetched and if that was the problem you should feel a tight spot, maybe even 0.01 mm ?

[lather]

Stuart,
forget the sandpaper, i think the best thing to use in the spindle is a stick of dynamite

shedhappens,
The adapter was ejecting when in neutral, with no gears meshing when turned by hand.
the gear clearances seem o.k. , though the splined gears have a fair amount of play on the shafts.

[pipeclay]

Maybe you should be trying to correct these inconsistent bumps in the spindle bore 1st ,it dosent sound good.

[jack620]

... the lathe is new and similar to an al 540,.. .

Sorry if this has already been covered, but is it still under warranty?

[Bryan]

Sorry if this has already been covered, but is it still under warranty?
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?

[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?

[Steamwhisperer]

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 :D

[Stustoys]

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

[shedhappens]

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 :C even with a crack with the copper hammer to side ?

Weird things tapers ?

[Oldneweng]

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

[shedhappens]

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 ?

[Oldneweng]

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

Dean

[Retromilling]

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 .

[lather]

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


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.

[Stustoys]

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

[lather]

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.

[Michael G]

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

[pipeclay]

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.

[Oldneweng]

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

[lather]

called the supplier about the issue, the service tech mentioned that it could not be caused by the bearings or bores being out of line and to email photos of the wear.
decided to take the plunge "as it would be a pain if the lathe had to be returned for repairs", and lapped the spindle taper using fine metal polish and oil,

Switched from the adapter and mt5 test bar frequently for about 1/2 hr, and ran the lathe on 100 rpm.
It worked, the adapter stays tight even at the highest rev, and takes a dam hard hit to remove.
what ever it was, it must have been out by a fraction, as the fine metal polish does not remove much material.

[Oldneweng]

It is good to hear that you solved it without major headaches. Enjoy using it.

Dean

[rusty steel]

Could the problem have been that there was a thin film of oil in the bore or on the adapter ? Russell

[Retromilling]

Could the problem have been that there was a thin film of oil in the bore or on the adapter ? Russell
Something like that , maybe transport grease that had dried to hard film in the small end .

[lather]

Cleaned the taper using wax and grease remover.
the adapter or testbar would still spin in the spindle if any oil, or the slightest remains of blue were on the taper.
could feel it grab in the same spot while using the polish, took some time to get a consistent polished surface on the adapter.