OOR with between the centers penturning...

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opfoto

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So I fnally got my live center on the lathe.....then my bushing....then my glued up blank then bushing then dead center....The blank met the chisel the rough went round and round.....finally when I approached the diameter I was hoping to sneak up on I noticed that The tail stock of the black was turning less than true!!!! Really... did my eyes go buggy...???

I know I used the mill to show the shiney brass after I glued them up....the bushings pop out as described by JohnnyCNC

I know I locked down the tailstock prior to turning....I know I twisted the dead center in as I mounted it....

I know I did not over extend the quill....

Where did I go wrong.....this wasn't supposed to happen.....

Murphy....MURPHY was that you???
 
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Lenny

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Is your tailstock retracted too far? With mine, it has to be extended about a half and inch for the live center to fully seat.

Do your centers line up when you bring them together?

Is the live center the type that unscrews to be lubricated? If so maybe it's loose.
 

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opfoto

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Is your tailstock retracted too far? With mine, it has to be extended about a half and inch for the live center to fully seat.
Great thought.......it was sticking out about an inch or so and when I seated it, it felt solid..... I did clean the tapers too!

Do your centers line up when you bring them together?
Last I knew they did...but honestly haven't checked that in a while.....hmmm
I wonder if there is a twist in the tail stock when I tighten it down into position, meaning play between the ways, (I have the aftermarket nut ,not the original on it.. (jet mini 1014 no vs))
Could that be a contributing factor???

Is the live center the type that unscrews to be lubricated? If so maybe it's loose.
Yes...I remember lubing (?) it a while back but never thought to check that... will check it!

Thanks for the thoughts.....will check them further and post again....I will try to take pics of the center alignment >< if it'll help....
 

nava1uni

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Make sure that the quill is clean. If there is any debris inside the tailstock the live center will not seat properly. I clean the tail stock and head stock often and it is amazing how much collects on the inside of each. Tiny sawdust makes things messy.
 

panamag8or

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Make sure that the quill is clean. If there is any debris inside the tailstock the live center will not seat properly. I clean the tail stock and head stock often and it is amazing how much collects on the inside of each. Tiny sawdust makes things messy.

Yes, especially if you drill on the lathe with the PSI chuck... it leaves a lot of debris behind.
 

Lenny

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Another good reason to leave your blank long, drill to just past the tube length and then cut the blank back. No more debris inside! :)
 

opfoto

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update.....

Everyone,

I have a lighted-swingarm magnified lamp next to the lathe so I used this for the inspection:

I checked the following.....
There is/was no slop/wiggle of the TS when sliding it to the left to mount the blank on the bushings,
The tapers were were clean, the quill(s) are clean.
The 60degree live center and dead center tips were both clean.
The bushings were brandy new, never used, etc.....true to JohnnyCnC as noted they "popped" out of the tube (both ends).

So in my infinite wisdom I remounted to the lathe everything except a glued up blank. I did use a plain tube and checked the spin...Looks great! I did not use my dial indicator to check for run out because I didn't notice any "wobble" any time even with the magnified lamp.

So I am left to wonder if the wobble came from,
A - Murphy
B - Blank wasn't totally squared to the tube
C - Blank wasn't milled totally on the TS end where the wobble was.

My thought it may have been C, Because I am almost certain that Murphy has his hands full with the elves and I don't understand how B could have happened. As a side note I was only running at 500rpm thru the entire process.

What I do know...thankfully... is the tooling looks to be running true. I will try again and and see if I have the same issue....I will update again either way.


Merry Christmas to everyone and may the New Year find us all happy and mostly healthy!
 

opfoto

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Update....Final

I just completed roughturning 16 slimline blanks TBC :)

I tried to replicate the conditions as listed above

I turned them all at 500 rpm

I checked the seating of the bushing at each end of the blank.

I gave the TS quill an extra twist to make sure the blank was mounted "snugly" on the lathe.

Not a single blank had the wobble (at either end) that I experienced before. :biggrin:

So I figure I need to pay more attention to the details of EACH and EVERY step necessary to complete each project!!! :wink:

Thanks to everyone for the suggestions, my cleaner mini lathe thanks you too!
 

Dale Allen

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One other thing that comes to mind is that the tailstock quill was not tightened with the side lever. I have done this a time or two when getting in a hurry or making rapid changes. If the side lever is not tight the quill can move slightly side to side.
With experience, you will notice this quickly and tighten the lever.:rolleyes:
 
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I never turn at 500 rpm. Usually way higher than that. Now for sanding and finishing this isn't too bad but I usually use double that for sanding and finishing also!
 

opfoto

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Do you usually turn at 500 rpm? I prefer to turn at near my lathe's top speed. Try it sometime. :)

Lenny,
Not normally but I wanted to slow it down a bit as it was my first time TBC and wasn't sure what speed to start with...as these blanks are only rough turned round, no where near final size. I will give a bit more speed....Not sure if I'll go full bore though....

Does speed make that much difference???

I can do 1 blank at 1/2 power then full power on the other blank.....and see if I notice any difference I suppose.

One other thing that comes to mind is that the tailstock quill was not tightened with the side lever. I have done this a time or two when getting in a hurry or making rapid changes. If the side lever is not tight the quill can move slightly side to side.
With experience, you will notice this quickly and tighten the lever.:rolleyes:
Dale,
I though that too and that was why I made sure this time I did it!!!

I never turn at 500 rpm. Usually way higher than that. Now for sanding and finishing this isn't too bad but I usually use double that for sanding and finishing also!
Mike(?)
See comments to lenny re: speed

Thanks again.....
 

Phillikl

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Don't mean to ninja the thread, but new to TBC and have a question along the lines.... Do you see whip with TBC like you do with mandril? I was always told, rough it out near max, then once its round, turn it down to about 1500-2000 for finish. This will drop the whip action and make the blank truer.
 

Lenny

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You shouldn't have any "whip" when TBC. That's kind of the point!
Drilling or applying CA glue at 500 rpm is ok, but when turning a small diameter like a pen blank you can increase the speed to 3600 or higher. When sanding I will slow it back down. Sharp tools and high speeds ... Give It'a try!
 

Stephen

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Do you usually turn at 500 rpm? I prefer to turn at near my lathe's top speed. Try it sometime. :)

+1 for speed - maximum speed available on your lathe. Of course very very sharp razor blade sharp chisels and light cuts, just kissing the blank. Good luck.
 

opfoto

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Lenny, Mike, Stephen

Will increase speed tonight. Will post again to let you know how I made out...unless of course you see blanks passin by your windows!!!

Thanks!
 

opfoto

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Increased the speed....

I bumped up the speed to 3975rpm or whatever the fastest setting is on my Jet mini. I was pleasantly surprised that nothing flew off the lathe. Then as suggested with light cuts, the blank was turned round and sized close to the bushing without a single problem. Feels smoother as well. I can get used to this. I just might stay with the TBC for awhile. Oh yeah...the OOR condition that started this thread ...gone!


Thanks
 
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