- Joined
- Aug 22, 2012
- Messages
- 4,271
I've just started turning down a shaft for the lead screw for my vertical slide.
Over a 200mm length it goes from 16.23mm at the chuck end to 16.22 to 16.20 to 16.11 at the tail stock.
I realise this is only a difference of 0.12mm or 0.0047" from end to end but it will make a difference in the fit of the final thread.
I checked the alignment using a shim between centres and it held vertical and at right angles with mild pressure but when I applied a bit more pressure the shim twisted slightly, the front edge tilting towards the chuck. The top and bottom stayed absolutely vertical.
To me this denotes that a mere hint of movement in the tailstock away from the front should bring this to spot on.
I guess what I'm after is do any of you think this is the problem and is it a sufficient miss alignment to produce the measured discrepancy over that length?
edit
Tomorow I will use a smooth rod to check the up and down movement in the carriage
Over a 200mm length it goes from 16.23mm at the chuck end to 16.22 to 16.20 to 16.11 at the tail stock.
I realise this is only a difference of 0.12mm or 0.0047" from end to end but it will make a difference in the fit of the final thread.
I checked the alignment using a shim between centres and it held vertical and at right angles with mild pressure but when I applied a bit more pressure the shim twisted slightly, the front edge tilting towards the chuck. The top and bottom stayed absolutely vertical.
To me this denotes that a mere hint of movement in the tailstock away from the front should bring this to spot on.
I guess what I'm after is do any of you think this is the problem and is it a sufficient miss alignment to produce the measured discrepancy over that length?
edit
Tomorow I will use a smooth rod to check the up and down movement in the carriage
