# Logan 820: How do I lock the cross-slide and compound?



## tmenyc (Apr 16, 2019)

Having a problem with slop/slippage on my cross-slide, enough that the toolpost bucks at the slightest pressure.  The slippage is completely north-south, the filister bolt holding the cross-screw nut is tight, the gibs are cleaned and tight.  At the handwheel there's about .015 slop and the whole handwheel to cross-slide screw seems a bit loose.  If I lock down the carriage the entire cross=slide assembly will shift, perhaps 1/64".  Mikey, who has been hugely helpful to this still-newbie, has recommended that I lock down the cross-slide to isolate the problem but I can't find anywhere how to do that.   
Also, this is a problem that has come up recently, after I replaced the two compound swivel bolts.  It did not happen before, but clearly, with those two bolts bent I had other problems.  Doesn't seem as if those would be the problem since all they do is enable the compound to swivel.  
Help please?  

Many thanks,
Tim


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## BenW (Apr 16, 2019)

I don't know whether this particular machine has a crosslide lock, but if there isn't one and you just want to isolate the problem, you could tighten the gib to lock the crosslide temporarily. 

Sent from my LYA-L29 using Tapatalk


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## ThinWoodsman (Apr 16, 2019)

https://www.hobby-machinist.com/threads/cross-slide-lock.41486/
Basically, yeah, tighten the gibs. You could also fabricate something a bit more usable, such as this or this.


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## francist (Apr 16, 2019)

Any chance those two new bolts you put in are just a hair long and not drawing the compound swivel down completely? If they're bottoming out beforehand they would probably still prevent the compound from rotating but wouldn't be drawing it tight to the cross-slide. Kind of like a T-nut with too long of a stud.

If I didn't have a problem before changing a part but had a problem after changing a part, I'd look strongly at my new part as being the problem.

-frank


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## Nogoingback (Apr 16, 2019)

Your 820 should be similar to my Model 200.  On mine, I was able to adjust some slop out by loosening the outer nut
on the x-slide handle and carefully taking up the slop with the inner nut.  It took a few tries, since tightening the outer nut changed
the adjustment but I got it in the end.  If you can do this, then any other slop in the x-slide will be the nut at the other
end of the screw that attaches to the x-slide itself. If it has significant wear, it will need to be replaced.  Of course the
screw could be worn as well.

Can't imagine why your x-slide would move when you lock the carriage.  However, the carriage has gibs that are adjustable
as well at both the front and the back.  (At least mine does.). Adjusting them might help.


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## tmenyc (Apr 16, 2019)

Frank -- my thinking, too, except that the compound is not moving; all the motion is in the cross-slide below it.  But yes, it was not present before the bolt replacement.  I'll check the bolts out.  They were from the Actuator, so I assumed they were milled correctly.
Alternatively, I'm wondering about  the cross-thread nut.  I had taken it out, cleaned it well, and reinstalled it a good month before the bolt replacement without a problem afterwards.  Is there any way it could be in wrong?  It is definitely bolted into place, and did not show a lot of wear, although a small amount worn off might not have shown.  Would ANY wear be too much wear?  I'll take it off tonight and photograph it. The cross-feed screw does not show obvious wear where it is visible, which (the two swivel bolts excepted) is consistent with the whole machine's condition.  

NGBack -- I will certainly do the adjustment.  With my understanding that "slop" is the looseness of the handle that results in turning the handle without changing the actual position of what the handle turns, my cross-slide handle is loose but does not turn without the cross-slide moving.  The .015 slop is longitudinal, on the carriage.  Will adjusting the cross-slide outer and inner nuts tighten the handle on the screw AND tighten the mechanism to possibly eliminate the lack of cross-slide rigidity?  

Thanks for the help.


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## Nogoingback (Apr 16, 2019)

If you had the cross feed screw out, you would see that there is a gear on it secured with a woodruff key which is sandwiched
between a shoulder on the shaft and the inner end of the bushing that supports the screw.  (The bushing is the part I'm
pointing to in the pic.)   So, if the handle is adjusted  to be loose, that allows some longitudinal movement in the shaft.
Adjusting out that slack with the nuts at the handle  eliminates that movement.  It's a fussy adjustment: too loose and you
get the movement, too tight and the cross feed handle binds and is hard to turn.  Of course, I'm assuming your lathe goes together
the same way mine does, but I'm pretty sure it does.  When you perform that adjustment, be sure that the setscrew on the
movable dial is loosened first.

The cross feed nut that moves in response to turning the handle is not adjustable.  Slop in that nut indicates wear in the
nut, the shaft, or both.   On my lathe, I replaced both parts which I ordered from Logan.  The shaft was expensive, the
nut not so much.  If you have much (rotational)  slop in the handle, changing out the nut would be a good place to start.

And again, I would check the gibs on your carriage as well.


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## tmenyc (Apr 16, 2019)

NGB -- many many thanks!  If I can get to it tomorrow evening that will be great; if not it will be (ugh) ten days, I have family stuff out of town.   Either way I'll certainly report back here. Sounds very do-able indeed, however.  I'm hoping the screw doesn't need replacement.  

Many thanks again.
Tim


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## tmenyc (Apr 28, 2019)

OK, I"m back from out of town, itching the whole time to get back here and solve this problem.  Tightening down the gibs did nothing except stop intentional movement of the cross-slide. I removed the nut, and as can be seen from the pictures, it looks fine, no apparent wear.  Threads are clean, no chunks, only casting marks.  

I removed the outer bolt on the cross-feed handle, and the handle, and then discovered that the inner nut cannot come off; there is a widening of the threaded slot, preventing it from moving further.  I'm guessing this is wear or damage, but when I tightened the micrometer nut the north-south slop disappeared!  Easing back a little bit, it could be turned without creating the slop.  Is this the solution?  
Is the widened portion a replacement need?  It does not seem to get in the way, and I'll see if handle slop returns when I reassemble.
As always, many thanks for the support. 

Oh, and by the way, Mikey send me a link to a video of a simple cross-feed lock, which I'll make as soon as I get this fixed. 

Tim


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## Chuck K (Apr 28, 2019)

Thread your cross slide nut onto the screw and check the fit at different points across the length of the screw.  It will probably fit looser in the center than near the ends.  If it's real sloppy in the center, it might be time for a new nut.


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## wa5cab (Apr 29, 2019)

Tim,

First, to get the inner nut off, try running a die nut onto the screw threads backwards.  That should clean up the damaged threads next to the keyway and allow the nut to get past the damaged area.  If it doesn't, try all of the die nuts that you have.  If that still doesn't do it, try an adjustable or split die nut.  That should do it.

Differential adjustment of the two nuts on the (probably 3/8"-24) threaded portion of the cross feed screw is how you adjust for minimum end float  of the cross feed screw.  That is best done with the cross feed nut run off the end of the screw and should be done before evaluating the crossfeed screw and nut for possible replacement.  You will probably need a thin pattern open end wrench to hold the inner nut while you tighten the outer one (what used to be referred to as Tappet Wrench).  It will probably take several attempts of loosening the outter nut and making a small adjustment to the inner one and then tightening the outer one before you are satisfied with the adjustment.  When you are satisfied with the end float (should be less than 0.003"), run the brass cross feed nut back onto the screw and use the dial to measure the backlash.  With a new nut, this will probably be 0.002" to 0.003" more than the end float of the screw.  With a used nut, it will be more than that.  Record or remember this reading.  Then crank the cross slide back to the region where it most often runs, and repeat the measurement.  With a new screw and a new nut, this reading should be the same as the first one.  How much more it is indicates how much wear you have on the screw (independent of wear in the nut).  At this point, it is up to you to decide whether to spend the money to replace nut or nut and screw.


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## tmenyc (Apr 29, 2019)

Robert --
Many thanks, really helpful and much appreciated.  That's tonight's work.  Hope I have that die nut.


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## wa5cab (Apr 29, 2019)

You're welcome.  I forgot to empathize to check what the threads actually are before attempting to run the die nut on them as I have no way to confirm that they are actually 3/8"-24.


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## tmenyc (Apr 29, 2019)

yep, don't worry.
Tim


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## gjmontll (Apr 30, 2019)

Attn; Tmenyc and wa5cab
   Yes the threads on the end of the cross-slide shaft are 3/8-24 UNF
   Greg (AC4WF)


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## wa5cab (Apr 30, 2019)

Thanks.


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## tmenyc (Apr 30, 2019)

thanks!


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## tmenyc (May 4, 2019)

Well, I got the UNF die nut, straightened out the threads, got the nuts and handle off ok.  Cannot seem to get the screw out completely, is there a woodruff key in there somewhere?  The cross-slide is much better now, much less slop.  BUT, the original problem of the tool not holding a DOC is still present.  It seems to buck off a facing cut and just move away from a turning cut.  And, there is still this small amount of south-north movement in the entire cross-slide assembly that won't go away.  
Appreciate your continued help.

Tim


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## wa5cab (May 4, 2019)

Tim,

In Downloads there is a copy of an 800 Series Operator's and Parts manual.  The pages are sorta numbered but not consecutively.  If you go to File page 35, you should see the LA-45-1 Carriage, with the saddle, cross feed screw, etc.  There is one Woodruff key near the center of the screw that prevents the LA-190 Idler Gear from spinning on the screw.  It is not obvious from the drawing whether the screw is removed to the front (after removal of the LA-689-A Bushing (called "Bearing" on most lathes)) or taken out the rear.  All that I know is that on an Atlas it comes out the front, and for several reasons I would try that first.  Which means removal of the LA-689-A.

However, I can't see how this would have anything to do with the movements you mention.  

To temporarily lock the cross slide to the carriage, tighten down the front and rear gib screws.

Which direction are you calling "north"?  Toward the headstock, toward the operator, or what?


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## tmenyc (May 4, 2019)

Robert, Mikey --
Mikey asked me to go back to the beginning and detail the symptoms of the problem.
Context is that I'm a newbie, but an analytical type.  My 820 is the mythical former shop teacher's pride and joy that sat unused for some years.  So, overall it is in great condition.  From January-March, as I got to know the machine in the little time I had for it, I restored it in subassemblies and really cleaned it out.  It worked fine, turning, facing cleanly.  The issues arose as I started my first projects.  
Issue 1. Over time, I noted replicability issues; there was/is a bit of slop in both longitudinal (what I call east-west) and lateral cutting.  I measured carefully each time, but could not pin down the ability to replicate a cut. 
Issue 2. The compound was just too difficult to adjust.  I disassembled it, discovered that both swivel bolts were bent, clearly the cause of my inability to get the swivel to work well.  This appeared to have been a traumatic injury, as if something fell on the compound or the compound was used to move the lathe; everything else around it was sound.) I replaced those through the actuator. 
Issue 3. When I got it all back together, it would no longer hold a cut, either turning or facing.  It bucks off the work for a cut of more than 5-8 thou, and with the less resistance the tool just pushed away from the work. I noted that the cross-slide, when pushed, moved appr 1/32", you could jiggle it back and forth.  Tightening down the gibs did not eliminate this (the 820 has no cross-slide lock, a project for the coming weeks with a friend with a drill press).  I could not tell if the loss of lateral rigidity (what I call north-south) has the same cause of the inability to hold a depth of cut.
Issue 4.  Based on the comments here, lateral slippage was excessive.  Based on advice here, the next step appeared to be disassembling the cross-slide more completely.  I removed the QCTP and compound again, removed the cross-slide thread nut, and this time opened up the handwheel and collar assembly.  It showed that the threads between handwheel and inside jam nut were damaged, perhaps from the same traumatic injury that bent the compound swivel bolts (one can imagine someone grabbing the lathe by the cross-slide handle and compound).  With advice from here, I located a 3/8-24 UNF die nut, repaired the threads, removed the nut.  As noted above, I was not able during this attempt to dislodge the woodruff key, so could not get the cross-slide screw out, but cleaned out a lot of old crap and reassembled.  (Robert, thanks for the download reference; I have that doc here and can now see the woodruff key.) The cross-slide slippage appeared to be much improved, showing almost no free turning of the handwheel.  

I tightened down the gibs, and it held tight, no lateral movement.  I stuck a test piece of steel into the chuck; it turned without slippage, but after releasing the gibs a quarter-turn and, with the first facing attempt it bucked, and now the lateral slippage is back again.  In fact, it's worse; the entire cross-slide now jiggles both longitudinally and laterally.  The carriage and saddle assemblies are firm and rigid. All of the motion is above, with the cross-slide.  When I tightened down the cross-slide gibs again, it holds firm. Are the gibs that sensitive?

This is where I am now.  Hope this description is clear.


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## GrayTech (May 4, 2019)

You checked the replacement bolts aren't too long? (Not actually clamping.)


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## mikey (May 5, 2019)

Tim, I mean no offense but your post is difficult to understand because of your terminology. It might be a good idea to use conventional nomenclature so we all understand what we're discussing. Movements along the longitudinal axis of the lathe is called the Z-axis. Movements across the lathe from the front to the back is called the X-axis. So, when we *turn* a work piece we do so in the* longitudinal or Z-axis*, and when we *feed in or face*, we do so in the *X-direction with the cross slide or compound. * I assume that when you say "longitudinal" you mean a turning cut and a "lateral" cut is a facing cut or you are feeding in a depth of cut. If this is not correct, please let us know.




_*Issue 1. Over time, I noted replicability issues; there was/is a bit of slop in both longitudinal (what I call east-west) and lateral cutting.  I measured carefully each time, but could not pin down the ability to replicate a cut. *_

Can you clarify this for us? Do you mean that you could not accurately dial in a specific depth of cut and expect the lathe to take that off the diameter?

_*Issue 2. The compound was just too difficult to adjust.  I disassembled it, discovered that both swivel bolts were bent, clearly the cause of my inability to get the swivel to work well.  This appeared to have been a traumatic injury, as if something fell on the compound or the compound was used to move the lathe; everything else around it was sound.) I replaced those through the actuator. [Issue 3.] When I got it all back together, it would no longer hold a cut, either turning or facing.  It bucks off the work for a cut of more than 5-8 thou, and with the less resistance the tool just pushed away from the work. I noted that the cross-slide, when pushed, moved appr 1/32", you could jiggle it back and forth.  Tightening down the gibs did not eliminate this (the 820 has no cross-slide lock, a project for the coming weeks with a friend with a drill press).  I could not tell if the loss of lateral rigidity (what I call north-south) has the same cause of the inability to hold a depth of cut. *_

Not sure what the "actuator" is but you replaced the swivel pins (I assume you mean the swivel pins, part # 180, that lock the compound down to the cross slide) and subsequently noted that there was excessive movement in the cross slide or the compound (do you know which one is moving?), such that a depth of cut more than 0.005 - 0.008" pushed the tool away from the work.

_*Issue 4.  Based on the comments here, lateral slippage was excessive.  Based on advice here, the next step appeared to be disassembling the cross-slide more completely.  I removed the QCTP and compound again, removed the cross-slide thread nut, and this time opened up the handwheel and collar assembly.  It showed that the threads between handwheel and inside jam nut were damaged, perhaps from the same traumatic injury that bent the compound swivel bolts (one can imagine someone grabbing the lathe by the cross-slide handle and compound).  With advice from here, I located a 3/8-24 UNF die nut, repaired the threads, removed the nut.  As noted above, I was not able during this attempt to dislodge the woodruff key, so could not get the cross-slide screw out, but cleaned out a lot of old crap and reassembled.  (Robert, thanks for the download reference; I have that doc here and can now see the woodruff key.) **The cross-slide slippage appeared to be much improved, showing almost no free turning of the handwheel. *_

So, it appears that fixing the damaged thread on the part of the leadscrew that takes up slack between the cross slide leadscrew and nut allowed you to reduce the amount of play in that assembly but ...

_*I tightened down the gibs, and it held tight, no lateral movement.  I stuck a test piece of steel into the chuck; it turned without slippage, but after releasing the gibs a quarter-turn and, with the first facing attempt it bucked, and now the lateral slippage is back again.  In fact, it's worse; the entire cross-slide now jiggles both longitudinally and laterally.  The carriage and saddle assemblies are firm and rigid. All of the motion is above, with the cross-slide.  When I tightened down the cross-slide gibs again, it holds firm. Are the gibs that sensitive? *_

Which gibs did you tighten - the cross slide or compound? Assuming you mean the cross slide gibs, your issues resolved until you loosened the gibs a quarter turn and the issue of "lateral slippage" recurred.

So, from what I can gather here, it appears that *the problem is that the cross slide gib is extra-sensitive*, such that you have to run it tight to eliminate turning and facing issues. Is this correct? If so, it implies that the gib or the dovetail is not flat or is not adjusted correctly. I am not clear on how replacing the swivel pins that hold the compound to the cross slide affects this other than that they now work properly and are transferring forces from the tool to the wonky gib situation.

Do you agree with the problem statement? If so, then the guys can maybe help you work through the evaluation and resolution of this problem. As we discussed, it might not be a bad idea to use some Prussian Blue to see what the contact pattern looks like under there. You might also take a really close look at the gib adjustment screws to see if there is any deformation at their tips. With luck, this might all be resolved by replacing the gib.


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## Tozguy (May 5, 2019)

The bent compound screws and the buggered keyway would indicate (as you mentioned) that some severe trauma has occurred. Considering all the adjustment work that has been done without solving the problem I am starting to suspect that the top of the cross slide might be cracked somewhere. Cracks in cast iron are not always easy to see so you need to look for them.


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## mikey (May 5, 2019)

This might be a good one to ask Richard King about.


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## tmenyc (May 5, 2019)

Mikey,
Thanks, as always.  Sorry about the bad terminology; I got in a bad habit with that from the start, will do it correctly from now on.  
You do certainly understand the problem statement, however clumsily it was worded.  
I got the Prussian blue, will do it today.  And, I'll inspect the cross-slide carefully for a crack, hoping to not find one.  

Also, the actuator is the Logan Actuator, lathe.com.  I believe it's either the successor or descendent firm.  
Tim


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## tmenyc (May 5, 2019)

And yes, reading your response again:  yes, my issue with replicating a cut was exactly as you note:  dialing in a cut, after accounting for the dial slippage, stopped being predictible.  For a few weeks, a cut I made, always in the .005-.010 range, was pretty close to that, usually over, .002 off.  But then, the error range started growing, and then it stopped holding a cut altogether as described.  Most of this was done on 12L14, at the .006 feed rate and 420 rpm, so should have been easy cuts.  
The problems started after I changed the swivel bolts, and while one might think that that might have caused it, my growing belief is that disassembly upset something that was on the edge of going wrong.  The compound swivel was clearly not functioning and had to be fixed, and that install was quite easy, and the compound is working fine now.  On to the gib.


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## tmenyc (May 5, 2019)

here are pictures of the cross-slide gib and gib screws, presented left to right as x+ to x-.  Is it meaningful that screws 1,2,and 4 are flat but 3 is rounded? All four screw indents in the gib appear the same, cleanly rounded.  Do you think the three flat end screws were inappropriate replacements?  The indent in the gib screw hole is approx .09" across, which matches the rounded end of the one screw, but the diameter of the flat screw ends is .154", so they would not fit fully into the holes.  Could that have created enough slack for the gib to slip during turning or facing if the gib screws were loosened enough to let the cross-slide move?  If so, why did it cut well for awhile but then not?  Was it maybe in a perfect gib adjustment that I haven't been able to replicate?

The smooth side of the gib has two scratches I can feel, just opposite the 1 screw hole and 2/3 of the way from screws 1 to 2. There is some wear on the x- end, with the sharp edge rounded down, almost like a radius on a cutting tool.

Many thanks, 
Tim


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## mikey (May 5, 2019)

I'm not a Logan guy but I'm going to guess that the flat-faced gib screws are the wrong screws. If so, they would spread force over a relatively broad surface area instead of being concentrated in a tiny part of the gib like the round headed one does. This could also put more force on the upper edge of the gib strip because this is where they would contact the strip. Furthermore, it looks to me like those flat screws were made that way; the tips look like they were inserted into a hole in the end of the screw. Makes you wonder if the former owner did this.

If this was my lathe, I would either make or buy the proper gib screws. I would also replace the gib strip and hope that this works well enough that scraping the dovetails of the cross slide won't be necessary. Ideally, the gib screws would be long enough to allow a locknut to be placed on the screw so they don't move once you adjust them.

I defer to the more experienced Logan owners. I may be totally wrong on this.


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## francist (May 5, 2019)

I'm not a Logan expert and I doubt that this will be the root of the problem, however I can't help thinking about something mentioned in a few posts earlier. About backing off the gib screws ".. a quarter turn.." In my world, that's actually quite a bit to back off. I couldn't find the gib screw size from the Logan manual and parts list, but even supposing they're #10-32 which would be reasonable, say. A quarter turn on a 32 tpi screw backs that screw away from the gib nearly 8 thousandths of an inch ( 0.0078" ). That's quite a bit, and way more than ample to go from a snug fit to a sliding fit. 

For what it would take, running the gib screws back in and then backing off less aggressively might yield some better results. Or not !

-frank


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## tmenyc (May 5, 2019)

Mikey,
I just wrote to the Logan Actuator to order the replacement gib and screws, in the hope that that will create enough of a solution. If it does, it also answers the "why now" question, as in "why did it work before"?  The answer is that I hadn't touched the gib screws before I discovered the bad compound swivel bolts.  IIRC, the entire saddle assembly was moved intact when we brought the lathe here.  So I'll bet that however they had been set before, to accommodate the flat screws, was still in place until I disassembled it to replace the swivel bolts.    Definitely hoping it's a cure.

Frank,
Your point is well taken; my quarter-turn was actually an estimate, it might well have been less, but am pretty sure it wasn't more.  I'm going to be more precise with the new gib screws and nuts in hand; these nuts are pretty worn and hard to work with precisely. 

Tim


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## mikey (May 5, 2019)

Let us hope that a new gib and screws resolves your issues, Tim.

This is an opportune time to make and install your gib lock. I suggest you make it in two parts. The part that goes into the hole and contacts the gib will not be rounded. Instead, I would use a piece steel round stock turned to just slip fit into the threaded hole you make and cut the tip at an angle that matches the angle of the gib strip. Be sure to deburr all edges well. Insert it into the threaded hole with the long end of the slanted tip pointing down. Then make a threaded locking screw that bears on the back of the first piece so that when you tighten the screw, it simply pushes on the first part to lock the slide with very little pressure. This type of locking mechanism is smooth, locks and releases well and does not cause excessive wear on the gib. I would avoid using a ball bearing for this kind of lock; it will eventually dimple the gib and cause alignment issues.

Once you have the new gib strip and screws in hand, maybe we can all go over our method of adjusting the gibs. There is more than one way to do this so a discussion might be a good idea.


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## tmenyc (May 5, 2019)

Mikey,
That makes a lot of sense; the ball bearing in the video did as well but I hadn't considered the wear it would cause.  So the inside (against the gib) side is the matching angle and the outside (against the screw) is perpendicular? Is a 1/8" hex bolt about the right size?  Or should I go up to 1/4"?  Since it will be a small piece, does it get ground to the angle and then parted off? 

Many thanks for sticking with me on this.  
Tim


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## mikey (May 5, 2019)

tmenyc said:


> Mikey,
> That makes a lot of sense; the ball bearing in the video did as well but I hadn't considered the wear it would cause.  So the inside (against the gib) side is the matching angle and the outside (against the screw) is perpendicular? Is a 1/8" hex bolt about the right size?  Or should I go up to 1/4"?  Since it will be a small piece, does it get ground to the angle and then parted off?
> 
> Many thanks for sticking with me on this.
> Tim



You're welcome, Tim. 

Yes, the part touching the gib is angled to match and the other end is flat, to match the tip of the screw that bears on it. I would size the locking screw so it is similar in size to the gib screws. 

First drill and tap the hole for the gib lock. Then find a rod that is a close slip fit in that hole. Grind the end of the rod to match the angle of the gib as closely as you can, then stick it in the lathe and part it off so it occupies about 1/3 the length of the threaded hole. Deburr all edges and you're good to go.


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## wa5cab (May 6, 2019)

Tim,

It may be my eyes playing tricks but those gibs look like just flat bar.  The thin edges should be milled at an angle of 30 degrees to the wide sides.  And the flat bottomed holes should be made at a 30 degree angle to the wide faces of the gibs.  The flat bottom holes would then be made with an end mill such that the holes would be parallel to the machined edges.  And the three gib screws that don't have the bevel on the tip look correct.  Not the one with so much bevel on the tip that it is almost sharp.


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## tmenyc (May 6, 2019)

Robert, 
I'm sure it's my photography, not your eyes.  Cell phone cameras don't do depth of field well.  The gib is absolutely slant-sided, and the holes do have sloped sides.  I'm hoping to get the new gib and gib screws in this week, so will see what a fresh set looks like.  On close inspection, there are other differences as well, so I have to wonder if these screws were pulled from a box o'gib screws at some point.  
Tim


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## wa5cab (May 6, 2019)

OK.  Just making sure.

Although I don't recommend using it as one of the four gib screws that remain in the machine, I do recommend keeping the bevel nosed screw as part of your maintenance tools.  Or bevel the noses of the other three screws only not quite as much.  First confirm that the holes are deep enough so that the full diameter of the nose does get into the holes, or at least across top quarters it does.  Then when you get ready to install the new gibs, start with the beveled one in the in the rear position.  With the bevel, it will be easier to make sure that you have a hole aligned with the screw.  Run it down just finger tight and then back it out just a few degrees.  Then start a new screw into the front hole and use something that will slip under the bottom of the gib to lift the front to align the hole with the screw, using only your fingers to turn the screw.  Then get the rest of the screws into the holes in the gib, replacing the rear beveled one with the last unbeveled one last.  You may also have to push on one end of the gib or the other to align the screw noses with their holes.  It can be a little ticklish getting all of the screws into place.  The compound gib will be easier to align with the compound off of the cross slide and inverted.  For practical reasons, you can't do that with the cross slide one.


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## tmenyc (May 6, 2019)

Robert,
thanks, really helpful.  

Tim


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## Nogoingback (May 6, 2019)

tmenyc said:


> Well, I got the UNF die nut, straightened out the threads, got the nuts and handle off ok.  Cannot seem to get the screw out completely, is there a woodruff key in there somewhere?  The cross-slide is much better now, much less slop.  BUT, the original problem of the tool not holding a DOC is still present.  It seems to buck off a facing cut and just move away from a turning cut.  And, there is still this small amount of south-north movement in the entire cross-slide assembly that won't go away. Iglesias it to check for wear.
> Appreciate your continued help.
> 
> Tim




Hi Tim, sorry I didn't respond sooner, but I've out of the country and unavailable.   If you pull the carriage, you'll see the gear is pressed onto the  the shaft and secured with a woodruff key.  If you insert something between the gear and the casting, you should be able to get it out with light taps with a compothane hammer.  Before you consider that, you can check some things first.  Screw the nut onto the shaft and wiggle to check for wear.  Even new parts have some play, but if there's lots  you need to consider changing the nut at the very least.  Check for slop where the shaft passes through the bushing screwed into the cross slide: it has a bronze bushing pressed into it that could be worn.

The replacement gib screws that Logan sells don't require nuts since they have captive plastic inserts in them.  I find they're easier to adjust.  When installing the gigs pay attention to orientation and ensure that the tips of the screws fit
into the indented spots in the gibs.  When you adjust them, snug them up evenly, and then back them off only enough
to allow movement in the cross slide.  It takes very little rotation of the screws to achieve this.


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## tmenyc (May 6, 2019)

Thanks!  I'm waiting to hear from Logan re buying the new gib and screws.  Acting on the theory of doing less before doing more, I"m hoping hoping that the gib screw issue will be my problem's resolution.  So, since I got a lot of the play out of the handle just with the nut adjustment, I won't take it apart now.  
Tim


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## tmenyc (May 12, 2019)

Nogoingback, WA5CAB, Mikey -- I just got back to town, and the replacement gib and screws had arrived from the Logan Actuator.  Yes, the screws have no nuts, and I can see the captive inserts.  However, the gib itself does not have indentations!  Can this be correct, or should I reach out to Scott Logan?
Many thanks for the directions for getting the screws in correctly.  I won't try, however, until I know that the gib is correct without indentations. It's also 1/4" longer, is that a problem?

best,  Tim


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## mikey (May 13, 2019)

Tim, I've only replaced 4 gib strips so I am by no means an expert at this but I will offer what advice I can.

New gib strips often come without the locating holes predrilled; that is a good thing because every lathe is different and it is better to drill them yourself. If you do some reading, you will find all sorts of opinions on which shape of screw point is best - round, conical, ball bearing, etc. Personally, I prefer the angled cylindrical insert that Emco uses because it spreads the forces from the screw over a broader area; whether this makes a difference, I am not sure but it makes sense to me. With that said, 3 of the 4 lathes I replaced the gib strip on used conical screw tips like yours and they seemed to work fine.

You will need to trim the gib strip to length. I suggest cutting to fit the length of the cross slide instead of matching the length of the old strip. Be sure to deburr the ends and all corners of the strip lightly, then sand the working faces with 400 grit wet/dry sandpaper laid on a surface plate or flat glass plate. You are just looking for a uniform surface here so go lightly and evenly. 

Clean the dovetails of the saddle and cross slide really well. Get up in the corners with a knife and get all the crud and debris out of there. Also make sure there are no burrs on the inside of the dovetail where the gib screws enter and clean the screw holes out really well. 

You are going to drill the four holes for the screws into the gib strip. Personally, I use a file to gently shorten and gently round the tip of each gib screw so that the sides of the tip bear on the gib strip hole, not the point. This spreads the forces out over a broader area. I use a spotting drill that is slightly wider than the included angle of the screw tip to drill the holes in the strip. Because the tip of the screw is cut back and blunted, the sides contact the hole instead of the very tip of the screw. Hope that makes sense. I use a spotting drill because it is short, rigid and only the point cuts. The flutes of a spotting drill are not sharpened so they do not cut; this eliminates the risk of damaging the threads in the saddle. 

Once the dovetails are cleaned and the screws are prepped, take your drill and pass it through the gib screw hole. You only need to drill about 1/3 of the way into the strip for each screw so pass the drill through until it is in far enough to give you that 1/3 depth and mark the drill on the outside with masking tape or a Sharpie; you will use this as a depth gauge when drilling.

Now you can put the gib strip and cross slide into place on the saddle. Pull the cross slide tight to the saddle, trapping the strip between them, and then clamp the cross slide in place if I can. On all the ones that I did, I was able to use blocks and clamps to do this. You are not trying to apply a lot of force; only enough so the strip cannot move. Look at the strip to make sure it is not cocked and then you're ready to drill. 

I prefer to drill the first hole, the one on the operator side of the strip. You are using the threaded hole as a drill guide and if you use a spotting drill, this works well. Shoot some cutting oil into the hole and drill to the depth of your marker. Once done, use compressed air to clear the chips and install a gib screw. Snug it down lightly; now the strip cannot move and you can drill the other three holes. Then take the whole thing down and clean all the chips out of the holes and gib space. Deburr the strip if needed and recheck to make sure no burrs were raised inside the threaded holes. Now you're ready to install the gib strip.

Most gib screws are long enough to allow a locknut to be used on the outside. If yours are too short for this, some Blue Loc-tite works well and allows you to adjust as needed without the screw vibrating loose. If you use Loc-tite, use it sparingly.

Oil everything up and install the cross slide and gib. I use machine oil for this. Install all four screws and gently thread them in until they just touch the strip, then back them off a tiny bit. Now you can adjust them. What you are trying to achieve is a smooth sliding fit with zero play. Since the saddle/cross slide assembly already has some wear, some screws may need to be adjusted more than others but you should be able to accommodate that wear. 

Using just moderate hand pressure, push the cross slide away from the gib strip so it fully contacts the dovetail on the other side of the saddle. Now you're going to adjust the screws and the easiest way is to work from the center on out to the ends. I adjust all the screws until they just touch the strip; this is enough to feel drag when you turn the cross slide handle. I fractionally back off all but the second screw from the front and turn the cross slide handle; you will still feel some drag. Adjust the screw just until the handle turns freely; this may only be a tiny fraction of a turn. Then I bring in the third screw until it touches just enough to cause some drag. I adjust that one until the handle turns freely. Repeat with the first and last screw, each time feeling it cause drag and then adjust until the drag just disappears. Once you are done, the cross slide should move freely but there should be zero side play when you firmly push across the cross slide with your hand. 

Done.

Hope this helps.


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## wa5cab (May 13, 2019)

I doubt that the 1/4" difference in length will matter.  But the gib should have the four flat bottom holes cut at a 30 degree angle.  Without them, the gib will walk out.  Also the new gib screws appear to be threaded to the end.

This is mostly tongue-in-cheek, but I wonder whether Logan and Clausing are using the same machine shop.  Two or three years ago, I bought a new carriage gib for the late Atlas 12", mainly to confirm that they were still steel and not plastic like the compound and cross slide ones had become..  It was also missing the flat bottom holes.  So were about 12 out of 13 on the shelf in their warehouse.  The sent me the 13th one and had the remaining 12 sent out for completion.


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## tmenyc (May 13, 2019)

thanks, Mike and Robert.
I wrote to Logan this AM to ask, based on Robert's response, if sending gibs undrilled is standard, on the chance that they'll do it for me.  Otherwise, I have to beg some time with a friend with shop to use his drill press.  Somehow I don't think this is a job for an unmounted DeWalt.  Mike, thanks for the instructions; I'll definitely use them.
Assuming I'll have to take it to my friend, I'll take advantage of the occasion and drill the cross-slide for the lock as well. 

Late-breaking news:  return email notes "must be drilled after assembly". 

best,
Tim


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## wa5cab (May 13, 2019)

Then you need to write back and get them to send you the drawing showing where the holes go, size, shape and depth.


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## tmenyc (May 13, 2019)

Robert,
Mike's note, #41 above, seems to cover the ground, no?  Although the hole difference from 820 to 820 can't be great, the only way I'd know it was correct is by using my cross-slide's holes. 

Tim


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## wa5cab (May 13, 2019)

Well, yes and no.  In the first place, Logan should never have sent you the gib without instruction on how to make it usable.  You've figured out, because you have asked, that you are expected to have to do something in order to make the gib usable.  But you still don't know how deep to make the holes, what diameter of drill bit to use, what the included angle on the nose of the bit should be (yes, that is a variable), and whether or not you should locate the hole positions with a spotting bit just small enough to go into the tapped holes and then finish them with a larger bit (which will require being able to hold the gib at an angle).

I don't approve of doing gibs this way.  It was only done to save the manufacturers a few cents.  The chances of ruining one of the holes while modifying the part and later during routine maintenance are pretty good.


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## mikey (May 13, 2019)

tmenyc said:


> Late-breaking news:  return email notes "must be drilled after assembly".



I have only done the gibs on two machined cross slides and two cast cross slides and it seems to me that the gibs for a machined cross slide could conceivably be pre-drilled. For a cast cross slide, I think it would not be practical to pre-drill them unless the maker used a consistent datum that is consistent for all their models. Bottom line is that it is probably more accurate to drill the gib holes yourself. I use a hand held drill for this - Makita, not Dewalt, but it works fine. 

You only need to drill into the gib deep enough to center the cone of the gib screws. This ensures the gib cannot walk. As long as the conical sides of the screws provide the pressure instead of the point, this should be sufficient. If you use the gib screw holes as a drill guide and use a spotting drill then the angle of the holes should be close enough to be correct and you won't mess up the threads in the hole. In a properly functioning gib set up, the screws do not put a lot of pressure on the gib; they only adjust the space between the sliding components that ride on an oil layer.


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## tmenyc (May 13, 2019)

Well, that's reassuring!  But, it will be a DeWalt...

Robert, I see your point.  I also see Mike's.  And, probably, you're both correct.  I don't know, and don't know if anyone knows, how alike one 820 is to another 820, but it's easy enough to get it right myself.  Instructions would have been nice, for sure, but I have your and Mike's guidance, which is sufficient.  I learned a long time ago in my world of vintage pen restoration that instructions for the brand and model and born-on-date don't necessarily fit the pen; I'm learning now that the lathe is a whole lot larger but the tolerances are a whole lot finer.  With pens, with some exceptions one generally shaves a bit here, adds a bit there, which is both the beauty and the challenge.  With the lathe, the challenge is getting it right to get it at all.  I'll certainly post when it's done.
Many thanks to you both.
Tim


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## wa5cab (May 14, 2019)

Pretty much all of the vintage American iron that gets discussed in these Fora originally came with flat bottom holes in the gibs and bull-nose gib screws.  The only reason for changing them would be to be able to make it cheaper.  And think about it - if the company building the lathe couldn't manage to get four holes to line up with four other holes, how could you expect any machine that they built to be able to produce decent parts?

I'm sure that the cheaper gib they sent you will work OK after you finish making it.  But this is an example of what happens when the bean counters get the upper hand.


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## Nogoingback (May 14, 2019)

It certainly would have been nice if the gib had the holes in it.  But, let's keep in mind,  the company that built the lathe
no longer exists, and hasn't for many years.  Scott Logan told me that he doesn't possess the original drawings for the older
machines, and so he may not know what the hole spacing is on that gib.  I suspect that has more to do with it than "bean
counter" shaving pennies.  I could be wrong, but my impression is that there aren't any bean counters involved and that
Scott makes all the decisions.  He supplies the parts he can, but they're parts for 75 year old machines that went out of
production decades ago.  If this lathe were a Sheldon or South Bend, the conversation would be about how to make a 
gib from scratch.


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## wa5cab (May 14, 2019)

OK.  I guess that I am too used to dealing with Clausing where, if they no longer stock the part, they almost always have the original drawings (at least for the lathes - less so for the mills and shapers).

In that case, the first thing to do would be to check the angle on the tip of the Nylon Patch or Nylon Rod gib screws that he was sent.  Be sure that it is the same as on the spotting drill and that the spotting drill just fits through the tapped gib screw holes in the side of the cross slide.  

I would suggest acquiring a roll of 0.005" and 0.010" shim stock and cutting enough strips to approximately center up the gib top to bottom in the slot that it fits into.  Shim both below and above the gib.  Use three round nose set screws to lock the gib immobile in the slot.  Spot drill the first hole, move one of the screws to that hole and drill the second one, and so on.  Then move the gib to the drill press and use a drill bit the diameter of a body drill for the screws and with the same included angle on the cutting end to enlarge the spot drilled hole to the diameter of the screws.  Use a depth stop to get all four holes to the same depth which, absent instructions to use something else, I would make around the depth for the body drill to be cutting to the full diameter.  

To pre-position the gib vertically for getting the gib screws into place, I would use the shim pack that was under the bottom of the gib for step one above.


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## Richard White (richardsrelics) (May 17, 2019)

I will do some drawings and suggest a great way to make a locking mechanism for these machines..


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## Richard White (richardsrelics) (May 17, 2019)

Tell me if this make sense...





So drill and ream the first hole, then drill and ream the second so the 2 holes intersect at 90 degrees, size is dependent on just how big your lathe is.
The second hole, from the side drill and ream thru an inch or so, and then thread the first 3/8 of an inch or so.

Next step take dowel pin, grind one end on a 45 degree, then make it so that the high side of the 45 degree end it fits at or near the top of the line of the horizontal hole. Make a second dowel, again with a 45 degree end to go in the side hole, the 2 angles meet and the screw applies pressure to the lathe making a nice stop. Get fancy and create a step in the vertical pin to allow a small spring to pull the pin from the base making it spring back up off of the main lathe. Personally, I have this on the wrong end of the cross slide as being on the back side is best. The front could allow the pin to drop out if the slide is brought too far back.

Yell at me if I messed up..
Regards

Richard


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## TomKro (May 27, 2019)

Tim,

  I've been away and just looked thru this thread. 

  I have some spare Logan parts and noticed that the cross slide from a Logan 210 uses a gib locating pin and the same style conical screws that Logan provided you.   This particular gib has no seats cut into it (but dimples on the back side from contact with the adjustment screws), and just one through hole placed to match a 1/8" gib locating pin mounted in the cross slide.   Here's a pic.  




  There appear to be quite a few different ways to locate and apply pressure to the gib plate.  

  One other thing - I inadvertently used long screws at the two locations for the cross slide screw cover plate (you can see the bottom of the tapped holes on the left side of the cross slide in the pic).  If those screws happen to contact the carriage casting, it can cause travel and gib adjustment troubles.   Not sure if this has been mentioned.  Easy to fix with a few washers.  

Good luck with the troubleshooting.

TomKro


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## tmenyc (May 28, 2019)

TomKro,
That's interesting.  I don't think the chip cover screws go through but I'll certainly check tonight.  
thanks,
Tim


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## Shiseiji (May 28, 2019)

Tim, just checking, are you aware there is a Logan group Scott moderates?  Also several members there who have been working on the 200s & 820's for decades. There are a couple of recent discussions on the cross slide dials that cover the little adjustment possible with the two nuts. I don't recall any gib discussions in the past couple of years, but they could be some in the archives. I can't get the link thing to work,  but it's  groups.io/g/lathe-list


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## ThinWoodsman (May 29, 2019)

Here are a couple of relevant threads:

Working without compound? 
Reducing slop in the compound of a Logan 1825 (10")

I couldn't get the search widget to work on the group page (grumble grumble javasript grumble), and google didn't help overmuch 820 "cross slide" site:https://groups.io/g/Lathe-List/

Out of curiousity, for people having trouble getting links to work, is that when using a phone on this page? I've never had a problem with the little "insert link" button (the two-link chain).


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## Shiseiji (May 29, 2019)

[QUOTE="ThinWoodsman, post: 665157, 

Out of curiousity, for people having trouble getting links to work, is that when using a phone on this page? I've never had a problem with the little "insert link" button (the two-link chain).
[/QUOTE]
Yes. And trying to balance turning the JS on and off. Not bad here, but on another site it can take literally 2 min for a page to load.


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## tmenyc (May 29, 2019)

Shiseiji, TW -- thanks, yes I know the Yahoo forum and have new topics come into my email.  But I had not thought to search it!  It's interesting that the yahoo boards are what the internet used to be...one forgets so easily.   And, it's also interesting that this is where Yahool started, and where it's ending...
Tim


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## wa5cab (May 30, 2019)

Quite a few of the Yahoo groups have moved to groups.io because of no tech support on Yahoo since 2016.  Most kept their same base names except that any underlines in the names were replaced with hyphens as groups.io doesn't allow underlines.  Which is actually good as most email managers underline links .  So the underlines don't show up.


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## tmenyc (Jun 4, 2019)

Friends, 
I'm happy to report that my Logan 820 is back in full operation.  It turned out that while the uneven gibs screws and worn gib were part of the problem, the main problem turned out to be that the compound rest top (LA683 for the early S/Ns) was not swiveling cleanly on the compound base (LA 691).  I was frustrated with my lack of ability to get the new gib strip indented properly with my tools and setup (which are being steadily improved), so took the whole assembly to the friend who found the Logan for me and has a complete shop.  He noticed it immediately upon disassembly; and indeed, once pointed out to me, the uneven wear couldn't be missed.  He put both top and bottom on his surface grinder, and the disparity became instantly apparent.  Once that was fixed, and he ground the swivel bolts down a couple of thou on his belt grinder, it fell together, and works wonderfully now.  
Mikey and others, thank you so much for sticking with me on this:  I've learned so much, both about dealing with metal and about how to use this wonderful machine.  Such a great board and community!

On to the boring bar sleeves Mikey described to me!

Tim


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## ThinWoodsman (Jun 5, 2019)

Well, that's good news - I wasn't sure a bad gib would cause the lift you mentioned you were getting, but the uneven base certainly would. Good thing you have a friend with a surface grinder, nice quick fix.


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