Cross-slide Lock?

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zimm0who0net

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So my carriage has a lock, but my cross-slide and compound don't. The compound is not that big a deal because I usually just retract it the whole way and that acts as a lock, but the cross-slide seems like it really really needs a lock. Especially on my small 6"x18" lathe, the carriage handle is so close to the cross slide handle that it's really easy to bump one as you're turning or boring and screw everything up. Why aren't locks a standard part of lathes? Milling machines, even small ones, tend to have locks on all their axes' of travel. Is there a quick and dirty way to add one?
 
I keep an Allen wrench handy to clamp down on one of the cross slide gib screws (one in the middle, the ends are set for snug. Usually it just sits there, riding along in the screw.
 
As Tom said, you can use an existing gib screw as a lock. You can also drill and tap a hole in line with the row of gib screws and add a separate locking screw. If you do this, slip a small ball bearing in the hole and maybe use a small Kipp-type locking lever to lock it - fast, simple and it will work.
 
Some lathe have what looks like a gib screw that is actually the carriage lock. It might be a tab longer than the other screws, and it will probably be in the center of the gib.
If you do not have one, just drill and tap for a small screw like mikey suggeted
 
zimm0who0net said:
So my carriage has a lock, but my cross-slide and compound don't. The compound is not that big a deal because I usually just retract it the whole way and that acts as a lock, but the cross-slide seems like it really really needs a lock. Especially on my small 6"x18" lathe, the carriage handle is so close to the cross slide handle that it's really easy to bump one as you're turning or boring and screw everything up. Why aren't locks a standard part of lathes? Milling machines, even small ones, tend to have locks on all their axes' of travel. Is there a quick and dirty way to add one?
Click to expand...

What I used to do if I didn't need the compound slide was to tighten the gib screws. You ask why more lathes don't have locks? Most of the time they are order from the manufacture and for a extra fee you can get them included. I consider myself luckly if I was assigned a lathe that had working stops or locks. I understand your frustration.
 
Mills will pull themselves into the work if the table isn't locked or if the handle isn't counterbalanced it will turn itself from the vibration. Mine does this often. I try to remember to keep my hand on it if it isn't locked or at least snugged up.
 
Well Zimm, that is a good point you raised. I had the carriage and apron all apart on my little lathe - so I figured I'd add a cross slide lock. I spaced it evenly between the gib screws, lined it up pretty, made a plug with the end cut at an angle to match the gib -- that was more than a year ago. I have used that lathe a decent amount, but have used the nifty little cross slide lock exactly zero times. :tranquility:

In fairness, before I got the small lathe and a milling machine, I used my other lathe for everything - including milling with a SB mill attachment that I worked out an adapter plate for. I would occasionally lock up the cross slide for certain tasks (per the recommendations above).

With most lathe work (at least the sort of stuff I've been doing), I know which way the work is going to be pushing. Certainly, the carriage lock makes sense (when the feed is off, there is nothing keeping the carriage in longitudinal position). For the cross / compound slides, once the tool load comes on, the back lash will get taken up and that slide cannot really go anywhere. With conventional machines, backlash is a fact of life (obviously lots of great work gets done on lathes that don't have a cross slide lock).

Deffinately for milling with a lathe, the cross slide lock is usefull. Perhaps if one were drilling from the tool post, the lock would be handy? I do have a tool post drill arrangement on my larger lathe (the one without the cross slide lock) - which, by the way is fabulous for large drill bits. Never noticed any problem - but drilling big holes is not a very precise task anyway.

Zimm, Perhaps your thread here will be the start of a survey on what applications a lathe cross slide lock would be useful for?

DSCF5874.JPG
 
Another situation where a cross-slide lock's useful is boring between centres, e.g. with a cylinder clamped down on the cross-slide and a BC boring bar. The cyclical forces from the rotating tool can alternately open and close the backlash in the cross-slide which gives an out-of-round cylinder and lots of noise and chatter, nasty... The whole point of BC boring is that it ALWAYS gives a geometrically perfect cylinder as the tool's always under the same engagement conditions, hence always subject to the same deflection, and the tool being between centres can only describe a circular path in the cut.

My lathe has a double cross-slide (two sets of dovetails, the lower set for the taper attachment, upper for the cross-slide) so I have two sets to lock - with taper gibs it's a simple matter of winding in the gib adjustment screw at the front of each dovetail, very convenient :)

Dave H. (the other one)
 
zimm0who0net said:
Why aren't locks a standard part of lathes? Milling machines, even small ones, tend to have locks on all their axes' of travel. Is there a quick and dirty way to add one?
Click to expand...


Not true, turret lathes often have axis locks on the cross slide, Warner & Swasey machines employ this feature. The simplest way to accomplish this is to drill and tap a hole through the side of the offending axis slide and install a hand knob that locks the lead screw so that you can't turn it without effort.

Engine lathes do not have axis locks because they are not needed.
 
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