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mimpi
17th July 2011, 11:36 PM
Hi I have just upgraded my old GMC lathe to a hafco wl46 lathe. I got a teknatool super nova 2 chuck and insert to match which only arrived Friday. I had a chance to fiddle today and noticed with the dead center in the headstock there is some slight runnout. I will bring a dial indicator home from work to check out what it is but to my eye it appears about 5-10 thou. Is this normal? because when I have the chuck mounted the wobble is visible. At first I thought it was the chuck or wrong insert. but stripping it back and bringing the tailstock up I noticed the runnout was actually in the headunit.

I will give Hare and Forbes a call as well but wanted to ask if I am being fussy?

Skew ChiDAMN!!
17th July 2011, 11:54 PM
There shouldn't be any obvious run-out in the drive shaft...

It'd also be a good idea to check inside the morse taper for cleanliness as any grit may prevent the drive spur from seating properly. (I'm ignoring the chuck run-out as that can be caused by a whole slew of other reasons)

Good luck, I hope it's only something minor!

Big Shed
18th July 2011, 10:41 AM
Like Skew said, there should not be run out, especially capable of being seen by eye, on the headstock.

I have the WL46 and there is no run-out on the headstock spindle, measured with dial indicator.

I would suggest you contact H&F and ask them to replace this lathe with one with no run out.

More info here (http://www.woodworkforums.com/f8/changing-guard-115302/)

mimpi
18th July 2011, 05:21 PM
thanks for the responses. I took a dial indicator home at lunch time and checked the headstock seems to be running quite true. the dead center is running at about 0.003" which hare and forbes told me is within tolerance for woodworking machine... so I put the insert on and it was running out pretty bad. around 5 to 10 thou.

So I can assume now that the problem is either the insert or the thread on the headstock. I took the insert and chuck into Carbatec as thats the company I bought them from here in Australia.

They couldnt tell much but checked I had the correct insert and that I had requested the correct insert. which I am pretty sure I did. 30 x 3.5 metric. So they swapped over my insert for another new one which I will give a try and hopefully solve my runnout problems.

I guess a question is how far do I tighten up the insert? there is no hole to lock it down with a grub screw so I assume I tighten until it cant tighten no more to prevent any slippage.

nosnow
18th July 2011, 05:48 PM
Hi
The SN2 does have a hole to insert a grub screw it is easily over looked as i missed it on mine
Cheers Rod

jchappo
18th July 2011, 08:30 PM
I found this to be a problem with a few 30mm 3.3 inserts.
I had two chucks, a G3 and an SN2, with run-out problems when using the 30mm insert.
Neither chuck showed run-out on a different lathe when using the 1" 8tpi insert.
Threading just the insert on to the nose of the lathe, and checking with a dial indicator showed no run-out.
Close inspection of the mating surface inside the throat of the chucks showed an internal chamfer just above the mating surface.
My solution was to spin the insert on the lathe and trim the matching chamfer with a file.
After a small amount of filing, I fitted the chuck and checked run-out, finding a small improvement.
Continuing filing and checking, I finally achieved acceptable run-out on both chucks.

Skew ChiDAMN!!
18th July 2011, 09:04 PM
There are, apparently, a couple of different types of inserts... so check whether your insert screws into the chuck body all the way.

All of mine screw all the way in until chuck body presses squarely against the shoulder of the hex and so long as the inserts are fully screwed in my chucks always run true.

Others appear to need the internal "end" of the insert to hold them square, and from what I hear they're the ones most people have runout problems with.

Robomanic
18th July 2011, 10:37 PM
I had issues with my Bonham 100 insert. Both with the grub screw kicking it off true, and with the clearance inside the insert. I left my grub screw out to get past that one but the trade off is that the insert is well lock-tighted in there.
As Skew mentioned, my insert seats up against the shoulder of the drive shaft, but there was 3mm of parallel section in front of the shoulder that fitted up inside the insert and that is what was binding. I never got to checking if it was the shaft or insert to blame, but I bored the insert out a touch so there was no more interference and it has run true ever since.

brendan stemp
19th July 2011, 10:10 AM
I would suggest there should be no run out on your head stock and you should not have to put up with it, even on a wood lathe. It is a very frustrating thing to put up with so if I ever bought a lathe that wasn't spot on I would demand a replacement.

rsser
19th July 2011, 05:51 PM
Teknatool inserts have a reputation.

mimpi
20th July 2011, 12:07 AM
I am witnessing this reputation first hand. I spent two hours on it tonight. I was able to determine that the head stock spindle is running very true and the chuck is also running true and the insert is running from 4 thou out near the head stock end to 8 thou out a whopping 1-2cm the other end of the insert. frustrating as this is the second insert.

I will call up the supplier of the lathe and see if they supply inserts that will fit the teknatool chuck. Failing that I am unsure what to do short of getting an insert custom made.

rsser
20th July 2011, 08:08 AM
IIRC a forum member here went through 3 inserts before returning chuck and insert for a refund. Others have been more lucky. But that's the T'ool QC for you.

You can get quality 3rd party inserts from these guys:

Vermec's Tools (http://www.vermec.com/id1.html)

rsser
20th July 2011, 09:05 AM
PS, but it may be the machining of the female that's the prob.

mimpi
20th July 2011, 09:21 AM
thanks for the link Rsser,

It is definately the machining of the female part of the insert. unscrewing the center itself whilst on the male part of the insert shows zero run out which leads me to thinking the problem is between the insert and the headstock thread.

there is a very remote chance its the thread of the lathe itself but thats a long shot.

edit: Just took my insert and chuck down to hare and forbes. tried the insert on their floor unit. Sad to say it ran better on their unit but sitll not perfect. I ask the guy about what can be done he basically said that wood lathes are not checked for runout as they are being turned by hand... i pushed for replacement headstock but no luck. To me it now seems the insert may well be out a little bit but not as much as I eluded to earlier. And a fair bit of the problem appears to be in the thread of the headstock even though the machined part of the headstock spindle is running true.

I know some engineering firms so may go down the track of getting them to remachine the whole headstock spindle or make a new one.

I can live with the runout for most all of the turning I want to do with the exception of boring holes using the tailstock where any runnout will be amplified.


rant over. thanks for all the advise provided fellas.

RETIRED
20th July 2011, 09:34 AM
Just out of interest, you aren't putting a washer on between the headstock and insert?

mimpi
20th July 2011, 11:52 AM
I haven't used any spacers of any type.
Whilst checking out out last night I did try with a bit of folded paper on the low spot to pad it out and it improved the run out slightly on that end.

I will have a crack at boring a 12" piece of wood from each end and see how well the two holes meet up. if they meet up well I wont bother correcting the issue any further but I know it will be putting more stress on the system that I would have normally expected.

rsser
20th July 2011, 02:25 PM
I was referring to the female of the chuck btw.

If your run-out total is say 10 thou, that's only 5 thou deviation from centre (Thanks for the lesson GJ).

Noticeable but not material for faceplate work unless you want to eg remount a foot for more turning, in which case you'll in many cases get more deviation from centre from other causes.

Robomanic
20th July 2011, 09:43 PM
Is it possible that the thread has been cut with a die and not on the lathe? It might be possible to remount the shaft in a lathe and touch up the threads properly (as well as the mating faces). This will remove material from the face of the threads and you would have more backlash inside the insert, but at least it would be true and should not weaken it noticably if done carefuly.

Grumpy John would be able to give a more expererienced opinion on this one.

good luck.

mimpi
23rd July 2011, 11:43 PM
Just to give a final update on how I got the chuck running nice and true...

Its a bit of a cringe :yeahright: effort but it seems solid and been working all afternoon with no issues still running true.

I took some plumbers tape that they use to prevent taps from leaking and wound it around nice and tight on the headstock thread and whacked the insert over the top it was a nice snug fit now and I was actually damn surprised to see it all ran very true.