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haggismuncher
15th September 2010, 07:42 PM
Just got my first ever chuck (Gary Pye's Gen3 100) and a great peice of kit it is too.

My question is about the screw insert,
just how much force should I have to use to fit a small blank (less than 100mm) on?
I had to clamp the screw in a vice today and wind it on because when I did in fitted into the chuck the screw rotated even when tightened up.
The internal part of the thread is 8.5mm but this was too tough even in the vice, in the end I used a 10mm hole and even that just felt like it too much effort to be right.

Mind you I was practicing on some very old (40 yrs) Tas Oak

Chris

robyn2839
15th September 2010, 08:43 PM
Just got my first ever chuck (Gary Pye's Gen3 100) and a great peice of kit it is too.

My question is about the screw insert,
just how much force should I have to use to fit a small blank (less than 100mm) on?
I had to clamp the screw in a vice today and wind it on because when I did in fitted into the chuck the screw rotated even when tightened up.
The internal part of the thread is 8.5mm but this was too tough even in the vice, in the end I used a 10mm hole and even that just felt like it too much effort to be right.

Mind you I was practicing on some very old (40 yrs) Tas Oak

Chris put the screw into the chuck tighten, drill the required hole then screw while the screw is in the chuck. if you screwed it then put into the chuck chances are is that you screwed it too far into the wood(it doesnt go all the way in )and then screw locates in such a way that it wont slip, try a slightly bigger hole it only has to be firm not tight then screw the blank till it tightens the wood against the jaws outer rim.bob hope i made it clear for you

haggismuncher
15th September 2010, 09:01 PM
put the screw into the chuck tighten, drill the required hole then screw while the screw is in the chuck. if you screwed it then put into the chuck chances are is that you screwed it too far into the wood(it doesnt go all the way in )and then screw locates in such a way that it wont slip, try a slightly bigger hole it only has to be firm not tight then screw the blank till it tightens the wood against the jaws outer rim.bob hope i made it clear for you

Thanks Bob,
I was screwing it about an inch into the wood which is as far as the screw sticks out of the chuck. What threw me was force needed would turn the screw within the chuck even when I had tightened up. There are slots in the screw, I assume to prevent slippage but nothing connects to them inside the chuck.

Chris

PS apologies for the mass of typos in the initial message.

brendan stemp
15th September 2010, 11:08 PM
Initial hole was way too small especially for the hard oak. Measure the external thread size and take away a smidge (perhaps 1mm) to get the drill size needed. You can go for a smaller drill bit for softer timbers. For small bowls you don't the entire length of the screw; I use mdf discs as packers to effectively shorten the length of the screw. the packers are placed between the chuck and blank.

robyn2839
15th September 2010, 11:50 PM
if you stood the screw facing upwards ther is he thread hen a horizontal slot all the way around the screw, the inside corners of the four jaws sit in this slot then tighten, only after you have done that,presuming the chuck is in the lathe, then you screw the blank onto the screw,when it is tightened the wood will sit against the jaws whicg acts like a face plate (sort of )bu instead of rour screws there is only one in the centre,if you get my drift,bring your tailstock in to rough it out to remove some of the waste then take tailstock away depending on what your making, personally i dont use screw ,i use a small faceplate or turn between centres till i can put a dovetail to suit the jaws and then chuck it up........might take some time working out the process for a whil but you wont look back after you become used to it .......................bob

scorpio_oz
16th September 2010, 12:05 AM
Thanks Bob,
There are slots in the screw, I assume to prevent slippage but nothing connects to them inside the chuck.


I have the same chuck set/ The screw with the four slots in it get gripped by one of the jaw sets. I think it is the standard 50mm jaws. Once gripped, I've never had it move at all, it sort of all grips in grooves and stuff.

If you have a look at the pic here.

Gary Pye Woodturning :: Gary Pye Woodturning - Gen 3 GPW100 Chuck (http://gpwoodturning.sitesuitestores.com/cgi/index.cgi/shopfront/view_product_details?category_id=1107136782&product_id=1107445143)

The four slots go in the space between the four jaws, and then you tighten it up. The lip/collar sits in a groove in the jaws.

I have tried to draw what I mean, the jaws are dark blue, the screw is black.

If it doesn't make any sense let me know and I'll organise photos.

Hope it helps.

Regards

-Gavin


PS.Already answered above while I doing the drawing.