Re: Extending cross slide travel -- what is the currently accepted best method?
For my needs, the LMS kit lacked extended travel away from the operator. I need to be able to move the tool holder past the chuck for a part I make. I have a fixture in a quick change tool holder that holds three small parts that get a 1.3mm slot milled it them. I put the end mill in the chuck and feed the parts past it to cut a screwdriver slot. Not optimal but when lacking a mill it works fairly well. And beats the way I was doing it, cutting a slot with a Dremel tool and filing each one by hand.?
Ryan
On Feb 21, 2022, 1:31 AM -0500, Tony Jones <tony@...>, wrote:
Ryan H wrote:
> I don't have access to a mill to cut the carriage and the LMS kit only addressed part of what I wanted to do so I did it all myself, on my lathe.
I have a mill, several.
Curious what was lacking in the LMS kit? it seems to achieve both more travel and relocating the travel. The same as "the Mike route". Obviously it's $$$ and not DIY
> What Mike means by "If I were doing this modification again then I would not mill out the carriage slot. Instead I would simply move the leadscrew nut 25 mm further back on the cross slide.
> This would achieve the same result as extending the slot" is that if you move the nut further back on the slide there's no need to mill out the slide. Moving the nut back accomplishes the same
> goal, giving the nut more room to travel towards the operator. Both ways effectively do the exact same thing and no milling is needed with just moving the nut farther back.
I understood the wording of what he wrote wrt accomplishing the same (and what you say isn't - no offense intended - any clearer) but I'm just not grokking it :-)? I suspect it won't make any sense until I take everything apart and re-read at which time I'll have an "ah ha!" moment.
I do like the idea of making a new screw from the perspective of also making a custom mated feed nut.? ? ? I'm assuming it would alleviate the need to do this:?
Thanks for the reply.
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Re: Extending cross slide travel -- what is the currently accepted best method?
Ryan H wrote:
>? I don't have access to a mill to cut the carriage and the LMS kit only addressed part of what I wanted to do so I did it all myself, on my lathe.?
I have a mill, several.? ??
Curious what was lacking in the LMS kit?? it seems to achieve both more travel and relocating the travel.? The same as "the Mike route".? Obviously it's $$$ and not DIY
> What Mike means by "If I were doing this modification again then I would not mill out the carriage slot. Instead I would simply move the leadscrew nut? 25 mm further back on the cross slide.
> This would achieve the same result as extending the slot"? is that if you move the nut further back on the slide there's no need to mill out the slide.? Moving the nut back accomplishes the same
> goal, giving the nut more room to travel towards the operator.? Both? ways effectively do the exact same thing and no milling is needed with just moving the nut farther back.
I understood the wording of what he wrote wrt accomplishing the same (and what you say isn't - no offense intended - any clearer) but I'm just not grokking it :-)? I suspect it won't make any sense until I take everything apart and re-read at which time I'll have an "ah ha!" moment.
I do like the idea of making a new screw from the perspective of also making a custom mated feed nut.? ? ? I'm assuming it would alleviate the need to do this:?
Thanks for the reply.
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Re: Extending cross slide travel -- what is the currently accepted best method?
I just finished up? an extended travel mod on my 7x a couple days ago. ?? I don't have access to a mill to cut the carriage and the LMS kit only addressed part of what I wanted to do so I did it all myself, on my lathe.? Mine ended up being pretty much what Mike did as I thought I had a new idea when I thought about moving the feed nut farther back on the carriage but it turns out Mike already had that idea, LOL!? I made my own spacer, 1.350" long from aluminum and drilled new mounting holes in the carriage that distance farther away from the operator.? That allows for the extended travel towards the operator.? I then made a new feed nut from 3/4" brass, mainly just because I wanted the nut and screw to be a "mated" pair.? The factory nut would work just fine.? For the feed screw I made one from a 12" piece of 12L14 steel.? By making my own new nut and screw I could thread the screw so it just fits the nut eliminating a lot of the backlash in the system without having to use the goofy factory adjusting system.? I ended up with a bit more than I wanted at around .008" but it's much improved. ? I originally thought about extending the original screw but in my opinion it was easier to turn a brand new one than try and extend the old one.? My screw is now about 10.5" long.???? :-D
What Mike means by "If I were doing this modification again then I would not mill out the carriage slot. Instead I would simply move the leadscrew nut? 25 mm further back on the cross slide. This would achieve the same result as extending the slot"? is that if you move the nut further back on the slide there's no need to mill out the slide.? Moving the nut back accomplishes the same goal, giving the nut more room to travel towards the operator.? Both? ways effectively do the exact same thing and no milling is needed with just moving the nut farther back.
Honestly, I have very... not even what I would call moderate skills, especially compared to many of the members here and this was a project that I was very capable of doing.? I bought 12" of brass and have 11" left and I bought 6 pieces of 12" 12L14 and have 5 of those left too.? I'm super happy with how it turned out.? Oh, the other thing I did buy for this project was live (rotating) center but it could be done with a dead center... but I wanted an excuse to buy live one, LOL.
My suggestion is to go the Mike route, moving the nut and make a new screw.? It was a fun project and my lathe has more capability than it did before.? Win Win situation!
Ryan
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Re: Extending cross slide travel -- what is the currently accepted best method?
My understanding is that the Gordon Scott mod moves the effective range of the leadscrew towards the operator (so you can cut wider material since you've moved the cut position relative to spindle).? However you're not gaining any additional travel.
has a so the effective range is increased plus moved towards the operator.
The Gadget Builder version appears to remedy try to increase the travel by adding an extension to the front of the shaft (which I presume is shown exposed out of the spacer in this image):??
This idea of a shaft extension is poo-poo'd on the?madmodder.page,? they seem to recommend a longer screw instead such as the above LMS.
I'm not understanding the "If I were doing this modification again then I would not mill out the carriage slot. Instead I would simply move the leadscrew nut? 25 mm further back on the cross slide. This would achieve the same result as extending the slot" comment on the?mikesworkshop page.
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Re: Extending cross slide travel -- what is the currently accepted best method?
I did Gordon Scott's method years ago & have been pleased with it.
Roy
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Re: Turning Brass and Aluminum on a 7x14
A wrap or 2 of adhesive backed aluminum tape (real duct tape) around the work or on the ends of the chuck jaws.
Pet peeve - there's no need to quench brass to anneal it! About the only things you're likely to run across that are affected by quenching are iron alloys & a few aluminum alloys; everything else can be cooled at any rate by whatever is the most convenient, keeping in mind that quenching can warp things.
Roy
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I replied to an ancient post.? My bad.? ?Brain in neutral.? Ignore.
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You probably paid for it when you paid for your inside track membership. It¡¯s 10% to us losers that don¡¯t join their club. ? Sent from for Windows ?
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From: Tony JonesSent: Sunday, February 20, 2022 6:29 PM To: [email protected]Subject: Re: [7x12MiniLathe] 20% H F coupon ? I thought HF had pretty much eliminated the 20%.? ?
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Extending cross slide travel -- what is the currently accepted best method?
I need to machine some wider material.
Googling I can find lots of approaches and I'm struggling with what is considered the best approach in 2022 (ideas tend to evolve).
Gordon Scotts:?
Gadget Builfers:???(extends on above but incorporates a handle extension)
Twinsquirrel:??(handle extension is frowned upon and there is mention of buying and cutting down a longer screw from LMS).
Mikesworkshop:??(referenced in the above madmodder,? made his own longer screw but at end mentions not lengthening slot in carriage [hindsight]).
Maybe if I take everything apart and pour over the above 4 threads in more detail the subtleties of the differences would become apparent,? but instead I thought I'd ask :-)
Thanks!
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Hi Ades workshop
He is starting a mini lathe work over
A different take
Dennis
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Re: Saddle/Carriage adjustments
After cleaning the metal chips out of the gears in the apron; I used
my scroll saw to make a plastic cover for the gears. To grease the
gears I used some Mobil synthetic grease. Now the carriage moves
easier and smoother. I've not turned anything yet to see what/if any
improvement was made. May try turning something tomorrow, maybe some
aluminum, to see if I made any improvement. Not exactly perfect, but
here's a pic of the cover I made before the grease was added.
Stan
On 2/2/22 10:31, John Mattis wrote:
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When I first got my mini-lathe, I fabricates a
plastic cover for the gears and dillie the cavity?behind?the
cover with some cup grease.
This was 20 years ago and I have had no problems with it.
Regards,
John Mattis
On Tue, Feb 1, 2022 at 4:32 PM
Bill Williams < BWMSBLDR1@...>
wrote:
Stan, a question that has been in the
back of my mind for a while is ¡°Is it possible to seal
the apron well enough to hold oil for lubrication of the
geartrain?¡± The oil level would need be only high enough
for the lowest gear to just dip into the oil. I would
follow up on this idea but my handwheel feed is working
so well unmodified that I hate to rock the boat!?? Bill
?
Sent from for
Windows 10
?
?
I decided
to take the apron off this afternoon and may have found
the problem or part of the problem.? When I turn the
carriage hand wheel with the apron off, there's a spot
that offers some resistance to turning. There are some
metal shavings inside the apron and gears too. Maybe a
good cleaning and making a cover for the gears is in
order. I have a piece of .05" thick plaskolite that I
could use for that purpose.? With the apron off, the
carriage moves back and forth pretty well. I don't have
the experience to know if it's too snug. I'll see how
easily the carriage moves once I get the apron cleaned
and put back on. I assume white lithium grease is what I
should use on the gears?
Stan
?
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Re: Saddle slop -- source, solution(s)?
You make a good point, Mark!
As long as it is performing to your satisfaction all is well. Over time the saddle should settle into a comfortable spot on it¡¯s own.
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Re: Saddle slop -- source, solution(s)?
Update.
I found some adjustment issues with my saddle's shimmed slide plates (say that 3 times fast!).? Their mounting screws had loosened up a bit over time, permitting the saddle to ride up a bit over the Vee as the saddle was twisted.? Tightening them up eliminated the indicator variation due to that, so I reinstalled my 3/4" test rod and performed RDM.? I saw about .0005" variation at the headstock end and zero to .004" as I rotated the spindle, so I believe that comes to misalignment a bit less than .002"? over a distance of about 10 inches.? The polished guide rod is very smooth so it's pretty good for this kind of test.? I didn't observe much evidence of bed twist as I moved the indicator along the bed.
I haven't performed RDM on the vertical axis yet.? I really need to switch over to using one of my DTI's for these measurements, now that I know the spindle is fairly well aligned.? I have a 15-0-15 and a 4-04 (.0005" and .0001") DTI I can use for this.
Visual examination of the saddle V revealed that about 25% of the V really is in contact with the bed V (based on the polish marks on the V).? Rather than scraping to improve the contact area, I'm thinking about using PSA-backed sanding paper strips attached to the bed to refine the saddle "V".? Pretty much as described by a document in the Files section.? The procedure doesn't alter the bed surface.? But as it stands the lathe does pretty well on steel so why fix something if it ain't broke??
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Re: Saddle slop -- source, solution(s)?
John,
I was in the process of performing RDM when I found the issue described in my original post.? Since the saddle is unstable there was no point in continuing with RDM until I figure out what's going on.
Based on your and other similar comments I definitely will check the carriage V.? Since the problem could be related to differential wear along the bed I will examine it as well.?
Thanks,
Mark
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Re: Saddle slop -- source, solution(s)?
Mark,
I ran into saddle slop and found it was caused by ridges in the carriage "V" on my lathe. It is worth checking for this since it is easy to detect and fix.? See:
Once the carriage slop is settled you might look at RDM as a method to check headstock alignment.? It is unclear from your description exactly how you made the measurements where the DTI reading was varying but it sounds much like the measurement used in RDM except that you weren't averaging to remove the effect of the test bar being held at a slight angle in the collet. The theory for this method of alignment is here:
If you poke around on that page you'll find more info on RDM and how it applies to use with your Thomsen guide rod.
John
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Re: Saddle slop -- source, solution(s)?
I hand scraped all the sliding surfaces of the carriage and cross slide on my 7x16. I was also able to get the cross slide scraped square so I am able to face square with .0002¡± concavity over 1¡±. ?I did no filing or lapping. It has not needed any further attention in the ten years since. A scraped surface also holds oil well in all the minute little pockets. The underside surfacesof the ways were well within .001¡± of parallel from the factory. That was a great help right from the beginning.
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Re: Saddle slop -- source, solution(s)?
I agree with Roy. The top surface of the bed is the only precision ground part of the machine, so don't lap or modify it. What you do is use the surface of the bed as your reference for modifying other areas.?
Get something greasy you can use to color a surface. Prussian Blue oil paint from an art supply store or online is the traditional choice, and a small tube will last you for years. I'm calling this "bluing" but you may use another color. (You can even use lipstick, if you have some handy that SWMBO doesn't want). You need something that won't dry out, so a Sharpie, etc., won't work.?
What you do is smear a very thin coating of the bluing onto the bed and rub the saddle lightly on it, then look to see what areas of the saddle got colored. You'll probably be appalled at how little contact you have. (If the fit were perfect the whole surface of the saddle would be colored).??
Then you scrape or file away the places that are colored and try it again.? That's removing the high spots. As you keep doing this over and over, more and more areas will be blue as you get better and better contact over the whole surface.
Mike Taglieri?
Some good comments!? ? ?Give me more homework :)
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Re: Saddle slop -- source, solution(s)?
Some good comments!? ? ?Give me more homework :)
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Re: Saddle slop -- source, solution(s)?
Mark,
I think .005¡± variation is a lot over 10¡±.
I think it sounds as if there is a issue with the fit of the saddle as you eluded to. Is the saddle pivoting or twisting on the ways? If so, do you think there is a possibility the saddle retainer plates are loose fitting and not holding the saddle down? It could also have something to do with the rack and pinion creating the twisting movement. You probably have to go through some process of elimination.
Dick
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Re: Saddle slop -- source, solution(s)?
The top of the bed is surface ground at the factory - it's the? reference surface for everything on the lathe. The mating surfaces on the carriage & HS are NOT ground & may well be misaligned. Check the vertical alignment & see if also varies along the length of the bed. I had to clean up the underside of the HS & deburr things for stability & add a small shim to get decent alignment in both planes. Similarly, the underside of the carriage is worth refining. I did away with the jack & clamp screws by shimming the slide plates. I was able to get things close enough that I had to file off the raised ridges from the serial no. being stamped on the bed.
Roy
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