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



## erikmannie (Jan 11, 2021)

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


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## dpb (Jan 11, 2021)

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


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## erikmannie (Jan 11, 2021)

dpb said:


> 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.


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## erikmannie (Jan 11, 2021)

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.


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## erikmannie (Jan 11, 2021)

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


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## erikmannie (Jan 11, 2021)

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.


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## ttabbal (Jan 11, 2021)

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.


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## mksj (Jan 11, 2021)

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


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## erikmannie (Jan 11, 2021)

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!


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## rogerl (Jan 11, 2021)

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


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## macardoso (Jan 11, 2021)

Here is how I maintained my cross slide lock and carriage lock on my 12x36 after DRO install. Custom lock levers were fabricated and aluminum spacers lift the DRO off to give enough room.


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## f350ca (Jan 11, 2021)

My 16 x 80 Summit and Hardinge HLV have no cross slide or compound locks. If you take the slack out of the lead screws nothing should move.

Greg


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## erikmannie (Jan 11, 2021)

rogerl said:


> 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



The first time that it came up for me was as described at the very end of Post #9 above. New A6 carbide insert, 380 RPM, 2.70” outer diameter.


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## mattthemuppet2 (Jan 11, 2021)

the 4 bolts on top hold the cross slide nut. My guess that the screw in the middle is for one or both of the following things: a) allows you to lube the cross slide nut and screw (handy), b) forces apart a split cross slide nut to take up backlash in the cross slide (also handy). Some experimenting should tell you the answer.


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## higgite (Jan 11, 2021)

mattthemuppet2 said:


> the 4 bolts on top hold the cross slide nut. My guess that the screw in the middle is for one or both of the following things: a) allows you to lube the cross slide nut and screw (handy), b) forces apart a split cross slide nut to take up backlash in the cross slide (also handy). Some experimenting should tell you the answer.


b) is correct, according to the manual, pg 31.

Tom


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## mattthemuppet2 (Jan 11, 2021)

ah, the old RTFM issue


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## benmychree (Jan 11, 2021)

Personally, I have only ever seen one lathe with a crossslide lock, it was a BIG Axelson lathe.  If gibs are kept adjusted snugly, I see no need for a lock.


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## ddickey (Jan 11, 2021)

I use mag scales and they do not cover the top slide lock.


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## Larry$ (Jan 11, 2021)

My PM1440 has the gib screws covered by the DRO scale so I made a lock for the head stock side. Just a block attached to the follow rest holes and a large brass screw that bares against the cross slide. The disadvantage of this design is if the chuck has the jaws sticking out far enough a collision is possible. I made a stop for the bed to prevent that when using the lock. Since it only takes two cap screws to install/remove I only use the lock when I feel the need. There is probably a better solution that leaves a lock in place.


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## erikmannie (Jan 12, 2021)

higgite said:


> b) is correct, according to the manual, pg 31.
> 
> Tom



I concur. There is a ball oiler right next to these bolts.


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## erikmannie (Jan 12, 2021)

mattthemuppet2 said:


> ah, the old RTFM issue



I went through every page of the manual (for the third time) immediately before creating this thread.


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## mattthemuppet2 (Jan 12, 2021)

sorry Erik, that was directed at myself as I should have been able to find it if I had taken the time to read the manual. Based on your comment I should change it to SSWIITFM, as in "seller should write it in the .... manual"


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## erikmannie (Jan 12, 2021)

mattthemuppet2 said:


> sorry Erik, that was directed at myself as I should have been able to find it if I had taken the time to read the manual. Based on your comment I should change it to SSWIITFM, as in "seller should write it in the .... manual"



It’s all good


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## AlanB (Jan 14, 2021)

One of the rarely discussed downsides of a DRO - it often covers up or makes access difficult to a few things such as locks and oilers. Especially a quick install as typically done by the dealer. Many folks re-mount the DRO or make other workarounds to fix this, or change DROs.


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