Where is the Cross Slide Lock on PM-1660TL?

[erikmannie]

I have been using my PM-1660TL for a few months now, & I have yet to find a cross slide lock.

I just went through the whole manual, & my best guess is that (1) there is no cross slide lock, (2) it is on the cross slide handwheel, or (most likely), (3) it is accomplished by manipulating the four bolts & set screw in the middle of the cross slide (picture below).

Does anybody know?

The 4 bolts and set screw that I am referring to are in the middle of both of the diagrams below. I have not messed with mine yet, so I don’t know how they work.

Reference:

https://www.precisionmatthews.com/wp-content/uploads/2019/03/Manual-PM-14-16-TL-Series.pdf

 

[dpb]

There’s no bolt on the right side of the cross slide?

 

[erikmannie]

There’s no bolt on the right side of the cross slide?

That is what I would have expected. That’s how it is on my other lathe.

That is where my DRO scale is located, so maybe it is blocked. I did not see it in the manual, but I will go look again.

EDIT: They call the cross slide a saddle in the manual. It starts on page 62. I do not see such a bolt.

 

[erikmannie]

Do some lathes not have cross slide locks?

Maybe one uses the gib adjustment screws for this?

Those 4 bolts in the middle, if loosened, enable the operator the tighten the set screw in the middle which pushes down on a wedge and (this is what I don’t fully understand) open a half nut which enables the operator to either (1) adjust the cross slide backlash, or (2) disengage the cross slide entirely so that one may use the taper attachment.

I don’t see how this would lock the cross slide.

EDIT: you do not manipulate these bolts as in (2) above in order to engage or disengage the taper attachment.

 

[erikmannie]

It also seems that it would be impossible to have a cross slide lock in a handwheel assembly.

 

[erikmannie]

My money is on: it doesn’t have a cross slide lock so use the gib adjustment screws for that.

EDIT: Wrong. The cross slide lock is blocked by the DRO scale cover.

 

[ttabbal]

On my 1127, the center gib adjustment screw lacks a locking nut and acts as a lock. The compound is similar.

The carriage is locked using a cap screw to the right of the cross slide. It looks like the others and looks like it should be holding the apron on. But one of them is loose. Sung it up, and it locks. My DRO scale is close to it, but I can usually work around it if I want to use the lock.

No idea if any of this is the same on the 1660.

 

[mksj]

It is under the DRO cross slide scale on the tailstock side. Two options that people do is either put some spacers between the scale and the cross slide or mount a cross slide lock on the other side. You can do a search on cross slide lock and should be examples. I added one to the headstock side which mounts to the follow rest bolts.

ERL-1340 Cross Slide Lock for DRO Equipped Lathes

Often when doing tight tolerance work one needs to lock the cross slide to get consistent diameters along the length of the cut. My ERL-1340 was fairly tight when new, but over time I did noticed slight shifts in the cross slide position from my original setting. I am using glass scales, and I...

www.hobby-machinist.com

 

[erikmannie]

You guys saved PM from a tech question because you guys have solved the mystery. Thank you.

I will remove the cross slide DRO dust shield, confirm the existence of this “center gib adjustment screw serving as a cross slide lock”, & then consider the options listed above.

I will have to solve this problem because I definitely use a cross slide lock at times. Today, for example, using the compound to turn a 1° or so angle for .005” to .025” radial cuts in 1045 steel did push the saddle toward the operator up to .0015”. Sounds like I can tighten my cross slide gibs a little!

 

[rogerl]

I have a 11" South Bend lathe and the cross slide only has gib adjusting screws. When would you use a cross slide lock?

Thanks
Roger L