Saddle stop

Since my Saddle travel indicator is on the Handwheel that ultimately drives the pinion engaging with a rack, I do not expect absolute accuracy. Indeed, I am surprised by the accuracy that it does provide, but do not regard it as a high accuracy measuring instrument.

In contrast, my stop, clamped to the bed and with a micrometer barrel is regarded as being more accurate, and is used where closely controlled lengths are required..

No doubt, if the power feed were not disengaged, or hand feed was were pressed home with vigour, the clamp might be displaced, or inaccuracy creep in because of the changes in clearances or deflections brought about by greater forces.

Maybe I am wrong in power feeding to just short of the stop and then hand feeding to bring the Saddle to rest gently against the stop. But that seems to work for me.

Howard

Clive,

The issue is that the clamp is a right fiddle to get the stop onto the bedway due to the proximity of the covered leadscrew to a couple of fiddly cap screws that act on the clamp plate. I had another look at it this morning and it occurred to me that I could probably modify it a little to either replace the cap screws with hex head screws or drill a hole through from the top and have the clamping action made from the top rather than underneath. Another job for the roundtuit...

Henry.

I have a spare micrometer head that I was thinking of using in much the same was on my Myford. However what is stopping me is protection against swarf and coolant...

Regards to all

Derek

Derek, I took my stop apart this morning and the thread is pretty crude (12mm fine pitch) so I'm not expecting it to be very accurate on its own.

Maybe you could fashion a cover to keep the worst off?

Henry

If that's 12x1mm sounds accurate enough for most jobs, especially with multiple indices.

Emgee

I modified the saddle stop on my Warco lathe to clamp using a bicycle quick-release wheel lock. This makes it very easy and quick to use.

If you are using imperial measurements, then a thread of 7/16 or 1/2 UNF has 20tpi which is 0.050" per turn. For metric, there are taps available in 12 x 1 and 10 x 1mm pitch and the bolt can be easily made to fit.

Emgee, yep probably, but its pretty unusual that I need that much accuracy on length anyway. As mentioned above I use a DTI with the top slide for accuracy, longer lengths I use slips.

Nigel, nice idea! We ought to make more use of those I think. I thought about trying it like you have but with just a screw. I've fitted a couple of M6 hex head screws and washers in place of the cap screws so its much easier to clamp now, I might even use it!