Unscrewing stubborn wood from wood worm screw?

[McAldo]

This is probably a pretty dumb question, but anyway.
I really wanted to try my screw chuck, as I never used before, so I mounted a not too well seasoned log on it and turned away for practise, then turned the rest into a screw chuck to finish a piece.
Then I left it overnight mounted, thinking of using it again as a glue chuck . The day after my little kid saw the thing and fell in love with it (??? little kids.. anyway..). Daddy, can I have it??? Uhh, sure son, just let me take it off.. ughh.. arghghgh
Obviously the wood shrunk overnight, getting overly close and personal with the screw.
I put on gloves for better grip, I banged on it with a mallet, swore at it profusely, to no avail..
So I put it in water and left it overnight hoping it would loosen up again (yes, I know, an idiotic idea, not just it didn't work, but yes, I had to spend 20 minutes sanding the rust away)

In the end, I drilled a hole on the side and unscrewed it with a knock out bar.

Aside of turning it free, is there any other way to unscrew a stubborn piece without damaging it?

 

[woodfarmer]

Now you have me worried, I just left a piece screwed to a faceplate for the night
Think in future I will grease the screws.

 

[Harry 48]

It should not get that tight if the hole you drilled is the right size for the screw chuck but if it does lock the spindle put a band clamp around the peace and unscrew it

 

[Paul Hannaby]

My screw chuck already has a couple of holes in the side for a bar to be inserted for additional leverage. Without that, occasionally I find the screw chuck unscrews from the lathe spindle rather than releasing the wood. Your solution seems to be the best one!

 

[Tazmaniandevil]

I completely wrecked the wood screw for my chuck by doing just that. I eventually lost the plot & took a mallet & wood chisel to it to release it from the blank. Completely bent the shank of the screw. I now use part threaded stainless steel coach bolts with the hex head cut off. They are a perfect fit in the chuck and if I can't get it out of the blank by unscrewing, I can just dig it out and bin it.

 

[thomvic]

It should not get that tight if the hole you drilled is the right size for the screw chuck but if it does lock the spindle put a band clamp around the peace and unscrew it

Absolutely spot on! The pilot hole diameter should be no more than 1mm less than the diameter of the screw. half a millimeter is enough for screws less than 6mm diameter.

Richard

 

[CHJ]

It should not get that tight if the hole you drilled is the right size for the screw chuck but if it does lock the spindle put a band clamp around the peace and unscrew it

+1 for that advise.


With most pieces you get more than enough grip if the drilled hole for mounting is a millimetre or so oversize of the minimum.

I turn holding spigots and true up the outers on rough 'bark on' blanks 200-250mm diameter on a 10mm screw.

Mine are home made with a square format thread but are much the same proportions as these;-

 

[winemaker]

That happened to me used the dog lead and a piece of wood :lol:

 

[Random Orbital Bob]

On a similar theme but not related directly.....Ive recently had the 4 screws in a faceplate sheer on me when unscrewing after turning the outside of some very dense (ancient) oak blanks. You know oak sometimes goes like rock...almost fossilised after its been down and dead for decades. I had two blanks in a row where on unscrewing the screws they just twisted the heads off and I then had to undercut a "ring" once reversed to pop out the piece of the middle that contained the buried screw bodies. All a bit of a pain. Now Ive never pre-drilled pilot holes for screws using a faceplate before. Ordinarily I use a Makita 18v impact driver to put them both in and out and have never had any problems. I guess for particularly dense blanks I should pre-drill 4 pilot holes??

 

[procell]

Bob
what type of screws are you using? chipboard screws are no good as they are too soft and tend to shear. Also as someone suggested a dab of grease or vaseline on the threads will help them stay free.

 

[Harry 48]

I normally use pilot holes for face plate work if the wood is wet or dense I use wax on the screws but some times they will shear off {as we all now NEVER use drywall screws they can be very dangerous }

 

[McAldo]

Thanks so much for the good advice everybody!
I actually wondered before drilling the pilot hole what size it should have been, and went for something probably 2 or 3mm smaller than the worm screw. Thing is, because the wood was probably too fresh still, at the end of the turning session ( a little vase) it loosened up and was getting a bit wobbly, so I would never guessed it might tighten up like that. Goes to show how little I understand of wood.
Next time it will be pilot 1mm less then screw, a bit of wax or paraffin and immediate removal after turning, just in case.

The band clamp suggestion is really good though! I rummaged around the shop trying to figure out what I could use, but it never occurred to me that the solution was quite literally in front of my nose.