Hi Ed,
I have never had that problem in the 6 or so years I have had my DRO fitted. My lathe is very similar to yours so it should be the same.
I am not sure whats happening to yours, but I would be checking the gibs as if there loose it might be moving from the sudden drive of the lead screw.
Backlash in the cross slide (and any other slide) is not going to make it do that and is a natural thing to have on a lathe. You can adjust it out as much as possible, but it might bind in other places or become loose. It will also wear the nut quicker the tighter you have it.
I am wondering if the gear selector passes the cross slide gear on the way through to engage which makes it move that little bit.
(03-05-2013, 10:34 PM)Dave J Wrote: Hi Ed,
I have never had that problem in the 6 or so years I have had my DRO fitted. My lathe is very similar to yours so it should be the same.
I am not sure whats happening to yours, but I would be checking the gibs as if there loose it might be moving from the sudden drive of the lead screw.
Backlash in the cross slide (and any other slide) is not going to make it do that and is a natural thing to have on a lathe. You can adjust it out as much as possible, but it might bind in other places or become loose. It will also wear the nut quicker the tighter you have it.
I am wondering if the gear selector passes the cross slide gear on the way through to engage which makes it move that little bit.
Dave
Dave,
It's not the gib. I already checked it. Your last comment about the gear is something else I was thinking it might be. I'll tear down the cross slide and make sure everything it tight and if it still does it then I'll need to dig deeper.
03-06-2013, 07:33 AM (This post was last modified: 03-06-2013, 07:34 AM by stevec.)
(03-05-2013, 10:34 PM)Dave J Wrote: I am wondering if the gear selector passes the cross slide gear on the way through to engage which makes it move that little bit.
Dave
I was figuring it might be some permutation of that also. It's the type of thing that one wouldn't notice without the DRO.
It may be the reason why I've wondered where I went wrong on that final cut the times when I've forgotten to lock the cross slide.
Ed, if thats the case maybe you should drill & tap for a lock on t'other side!
(03-06-2013, 07:33 AM)stevec Wrote: I was figuring it might be some permutation of that also. It's the type of thing that one wouldn't notice without the DRO.
It may be the reason why I've wondered where I went wrong on that final cut the times when I've forgotten to lock the cross slide.
Ed, if that's the case maybe you should drill & tap for a lock on t'other side!
I also wondered why I would overshoot my intended dimension when turning to diameter. I just chalked it up to ineptness.
I'm definitely going to get that cross slide lock moved but only after I've tried figuring out why the cross slide is moving. Putting a functioning lock on will just mask the problem if I don't try to figure out the source.
I would steer clear of putting the lock on the opposite side as it will push the cross slide off the 2 true fixed surfaces the cross slide has.
I haven't done mine yet but plan to mill out a section on my backing spar that the scale sits on, thin down the head of a bolt to suit the original lock thread, then thin down a spanner to fit the slot.
This will then able you to use the standard lock and have it pull the cross slide against the dovetail as the factory designed it.
The scale is still fully protected as the backing spar covers it. If you don't have a backing spar, a 10-12mm one is not going to restrict the tailstock that much more. A 8mm opening would give enough room for the head of the blot to be undone.
(03-06-2013, 09:10 PM)Dave J Wrote: I would steer clear of putting the lock on the opposite side as it will push the cross slide off the 2 true fixed surfaces the cross slide has.
I haven't done mine yet but plan to mill out a section on my backing spar that the scale sits on, thin down the head of a bolt to suit the original lock thread, then thin down a spanner to fit the slot.
This will then able you to use the standard lock and have it pull the cross slide against the dovetail as the factory designed it.
The scale is still fully protected as the backing spar covers it. If you don't have a backing spar, a 10-12mm one is not going to restrict the tailstock that much more. A 8mm opening would give enough room for the head of the blot to be undone.
Dave
Dave,
You make some good points. I think I understand what you are saying about using a thinned down wrench to get at a thinned down bolt head but what the heck is a backing spar?
Hi Ed,
What I mean by a backing spar is just a piece of aluminum solid that the scale mounts onto, then it mounts onto the cross slide, you can see it in the picture sandwiched between the scale and the cross slide.
My scale is already mounted on one so it only a matter of milling it out.
You can mount a couple of nuts in your 3 jaw to hold and machine the bolt head down. You might have a thin spanner laying around, if not either mill it down or grind one down.
I will try to get mine done in the next week or so and put up some pictures.
(03-07-2013, 06:37 AM)Dave J Wrote: Hi Ed,
What I mean by a backing spar is just a piece of aluminum solid that the scale mounts onto, then it mounts onto the cross slide, you can see it in the picture sandwiched between the scale and the cross slide.
My scale is already mounted on one so it only a matter of milling it out.
You can mount a couple of nuts in your 3 jaw to hold and machine the bolt head down. You might have a thin spanner laying around, if not either mill it down or grind one down.
I will try to get mine done in the next week or so and put up some pictures.
Dave
Dave,
Thanks for the explanation. I mounted my scale using two small angle brackets on both ends of the scale the angle brackets are mounted to the cross slide. A chunk of aluminum is mounted to the saddle and the reader head is mounted to that. I'll add a better picture this evening. This picture only shows the angle brackets and the new carriage lock I had to fabricate to make room for the scale.
