|
Hello, All, I am having an issue with my mini-lathe, in that it seems to have excessive backlash in the Z-axis. (I.E., from the leadscrew to the carriage.) Backlash seems to be about 1.00 mm / .040 inches, which seems like a LOT as my Z-axis pitch is 0.0625 inches You may be thinking that this doesn't matter, and it doesn't if you use change gears, as long as you move your threading tool beyond the end of the part being threaded by at least this Z-axis backlash. But if you are using any kind of Z-axis digital control, it is an issue. I probably have a mechanical problem, for which I will now look, but this made me wonder: what IS the typical Z-axis backlash on a mini-lathe? If any of you have measured it, or can measure it easily, I'd appreciate your replying with your findings. Many thanks! -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
Leadscrew/carriage backlash on my Grizzly 7x12 8688 is around 10 thou
toggle quoted message
Show quoted text
On Wednesday, November 11, 2020, 9:11:39 AM PST, CLevinski <clevinski@...> wrote:
Hello, All,
I am having an issue with my mini-lathe, in that it seems to have excessive backlash in the Z-axis. (I.E., from the leadscrew to the carriage.) Backlash seems to be about 1.00 mm / .040 inches, which seems like a LOT as my Z-axis pitch is 0.0625 inches
You may be thinking that this doesn't matter, and it doesn't if you use change gears, as long as you move your threading tool beyond the end of the part being threaded by at least this Z-axis backlash. But if you are using any kind of Z-axis digital control, it is an issue. I probably have a mechanical problem, for which I will now look, but this made me wonder: what IS the typical Z-axis backlash on a mini-lathe? If any of you have measured it, or can measure it easily, I'd appreciate your replying with your findings. Many thanks!
--
Regards,
Charlie
New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
Charlie, do you have the two half-nuts, or a single half-nut and retainer like mine has? A worn out half-nut or half-nuts, or loose screws on the retainer or half-nut(s), the shaft(s) in the groove cam, or the channels in the groove cam itself could be worn. Might also check to see that the rack screws are all tight, and the rack is not worn. Can't get rid of all of the backlash, but should be able to reduce it. Yours gets a lot of use, so it could have only one problem, or several. There are probably other things I didn't think of. I was just looking at the carriage portion of the parts diagram for my HF 7x10 model 93212. Yours could be wildly different from mine, as mine is strictly stock in that area.?
HTH!
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
On Wednesday, November 11, 2020, 11:11:39 AM CST, CLevinski <clevinski@...> wrote:
Hello, All, I am having an issue with my mini-lathe, in that it seems to have excessive backlash in the Z-axis. (I.E., from the leadscrew to the carriage.) Backlash seems to be about 1.00 mm / .040 inches, which seems like a LOT as my Z-axis pitch is 0.0625 inches You may be thinking that this doesn't matter, and it doesn't if you use change gears, as long as you move your threading tool beyond the end of the part being threaded by at least this Z-axis backlash. But if you are using any kind of Z-axis digital control, it is an issue. I probably have a mechanical problem, for which I will now look, but this made me wonder: what IS the typical Z-axis backlash on a mini-lathe? If any of you have measured it, or can measure it easily, I'd appreciate your replying with your findings. Many thanks! -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
Thanks, Jonathan! -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
Bill, My lathe (a Real Bull) has two half-nuts. I removed the lead screw covers, and was able to determine that the issue was the three small adjustment screws as seen on the far right of the apron below. These were all loose. Readjusting them got the backlash down to 0.0015 inches! Thanks to you and Jonathan for your replies...  -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
That's great, Charlie! Glad I could be of some assistance. One of these days, you might want to put some of the low-strength loc-tite in there. Next time you have to do this, not now. If it ain't broke, don't fix it! ;)
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
On Wednesday, November 11, 2020, 01:18:29 PM CST, CLevinski <clevinski@...> wrote:
Bill, My lathe (a Real Bull) has two half-nuts. I removed the lead screw covers, and was able to determine that the issue was the three small adjustment screws as seen on the far right of the apron below. These were all loose. Readjusting them got the backlash down to 0.0015 inches! Thanks to you and Jonathan for your replies...  -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
Good idea, Bill! I have some material that a friend recommended that is intended to prevent screws from vibrating loose, and supposedly allows you to remove and replace them 3-4 times before having to reapply. I tried it and found that, in my application, at least, I had to reapply it almost immediately. It's called Threadmate VC-3 by Vibra-Tite. I may try this as I don't plan to remove or readjust the screws at all, if I can help it. BTW, I first met Lazarus Long in "The Number of the Beast", although he had only a short appearance. -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
I first met him in Methuselah's Children, long, long ago. I own most of the books he appears in in hardback. Takes up a lot of my space. Makes it kind of hard to shoehorn the machine tools in, sometimes. ;)?
Vibratite Threadmate is kind of waxy? I think I've run into it or something like it before somewhere, before I got into machine tools. Got converted to a Loc-tite fan working as a mechanic in an industrial laundry. Loc-tite 222 purple is what I was thinking of. It's for screws under 1/4" or fine threads. Not cheap, but worth having in your bag of tricks. Amazon has a Vibratite equivalent on the search page for Loc-tite. It's cheaper, but I've had good success with all the Loc-tite products I've tried. Not that I've tried all of them. :)?
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
On Wednesday, November 11, 2020, 03:32:32 PM CST, CLevinski <clevinski@...> wrote:
Good idea, Bill! I have some material that a friend recommended that is intended to prevent screws from vibrating loose, and supposedly allows you to remove and replace them 3-4 times before having to reapply. I tried it and found that, in my application, at least, I had to reapply it almost immediately. It's called Threadmate VC-3 by Vibra-Tite. I may try this as I don't plan to remove or readjust the screws at all, if I can help it. BTW, I first met Lazarus Long in "The Number of the Beast", although he had only a short appearance. -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
Thanks Charlie for this post, now I need to check my Real Bull for Z backlash. I have not motorized the Real Bull yet.
Ralph
On Wed, Nov 11, 2020 at 5:01 PM Bill in OKC too via <wmrmeyers= [email protected]> wrote: I first met him in Methuselah's Children, long, long ago. I own most of the books he appears in in hardback. Takes up a lot of my space. Makes it kind of hard to shoehorn the machine tools in, sometimes. ;)?
Vibratite Threadmate is kind of waxy? I think I've run into it or something like it before somewhere, before I got into machine tools. Got converted to a Loc-tite fan working as a mechanic in an industrial laundry. Loc-tite 222 purple is what I was thinking of. It's for screws under 1/4" or fine threads. Not cheap, but worth having in your bag of tricks. Amazon has a Vibratite equivalent on the search page for Loc-tite. It's cheaper, but I've had good success with all the Loc-tite products I've tried. Not that I've tried all of them. :)?
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
On Wednesday, November 11, 2020, 03:32:32 PM CST, CLevinski < clevinski@...> wrote:
Good idea, Bill! I have some material that a friend recommended that is intended to prevent screws from vibrating loose, and supposedly allows you to remove and replace them 3-4 times before having to reapply. I tried it and found that, in my application, at least, I had to reapply it almost immediately. It's called Threadmate VC-3 by Vibra-Tite. I may try this as I don't plan to remove or readjust the screws at all, if I can help it. BTW, I first met Lazarus Long in "The Number of the Beast", although he had only a short appearance. -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
|
Ralph, It turned out to be an adjustment, which would be proper to make for full manual use as well. If you don't have lead screw covers, you need not even remove anything to make the adjustment. -- Regards, Charlie New Jersey, USA
?
ANTHONY’S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop.
THE LINDO COROLLARY: If you have cats, they will promptly hide the tool.
|
Bill in OKC too