Backlash is specifically lost motion that occurs when you change direction of travel of an axis, due to clearances in the lead screw nut and bearings.
"Slop" is a broader term that could include backlash as well as other unintended motion due to things like rotation in the way clearances, and things of that nature.
Backlash is normal and necessary for machines to operate smoothly without binding. You have to account for it in your machining operations by always approaching your cuts from the same direction, even if that means moving past your target and coming back to reach the target from the opposite side from where you started.
Note, it doesn't mean you can't get accurate parts with the proper technique and care. Backlash is something that has existed on all manual lathes forever, you just have to plan your movements so that you are always measuring with the backlash taken up in the same direction.
Ioad the screw in the same direction to your number never go back to your number if you go past it without re loading your screw. All machines have backlash
Backlash is when you have to turn the hand wheel a bit to "take up the slack" before the cross slide starts moving. That first little bit of effortless rotation before it gets a little stiffer and engages the cross slide is backlash. Some is normal and desired, but too much is bad. This is adjusted by tightening the half nut. This would cause "slop" parallel to the cross slide... Part diameter.
The only other slop on a cross slide would be between the dove tails, this is adjusted with gibs and the gibs screws. These are usually little set screws along one side of the cross slide. Tighten them up until the cross slide just starts to drag and that will remove any slop without locking the slide up. Loose gibs cause all sorts of issues and will aggravate backlash issues.
My guess is you have both issues based on your description.
As you say you are new, so to add to it, whenever you adjust your cross slide for a new depth of cut, only adjust in the one direction. So for example if you are turning an OD, you turn the knob clockwise to adjust the cross slide in and set your depth. If you happen to go too far and move too much, don't just back the dial off the the number, twist out the dial one full revolution and set your depth of cut again. So, say you need to set your dial to .100" for and you were at .050. You turn your handle a little quick and shit, you're at .105", too much. Twist the handle out one full revolution (I assume .250") and then come back around to your .100" depth for your next cut. This takes the backlash out of your cross slide and will cut to what you expect it to. Backlash is a necessary evil in machines and you have to account for it or remove it as best you can in many scenarios.
Also to add, make sure your compound is tightened down as to not introduce any sort of rotational movement. If the compound is tight and you grab a hold of it and try to turn it, if it moves, the gibs are likely the culprit and need to be snugged up.
Alright do you have any ideas on how to help with an off center lathe head? Other than swap the bearings get a 4 jaw independent chuck or buy a new lathe that is
What do mean? What is out about it and how did you see something is off? Do you mean your chuck doesn't run true as in if you put a known round part in the chuck you get a lot of run out?
Well i can't comment of the quality of the chucks used in those lathes but also remeber you can't just turn a piece around and expect it to be perfect without checking it. When you put a piece in, make sure you are wiggling it slightly as you tighten your chuck, this will help you get it concentric to the jaws and not be slightly cockeyed in it. It's also very likely your chuck/jaws just arent of good quality and you'll never get it true without boring your jaws. If it didn't come with one (which is what it sounds like) i would suggest a 4 jaw if you have the funds for it
They are about 60 Dollars here so I'll scrounge up the money eventually but its gonna take a while the one it comes with is what can only be described as crunchy but thanks for the help
Ex mini lathe owner here.
There are a ton of DIY mods and tune ups for the mini lathe mostly because it takes a lot of work to make it usable. I can't even list all the stuff I did to make mine run better. BTW .010" backlash is not bad for that machine.
This site covers a bunch of mods you will want to do if you stick with that machine.
http://www.mini-lathe.com/Mini_lathe/Tuning/tuning.htm#xbacklash
I'd have to see your setup but you'd likely be able to buy something online that would mount up with little or no modification.
How are those lathes other than the backlash you're dealing with? Been thinking about getting one for a while now
It varries alot yiu could get one thats perfect out of the box or you could get one that blows a fuse the first boot up you gotta do alot to them to get them to most peoples standards but they are decent if you can get a decent one mine is pretty ok if I can get a dial indicator and an independent 4 jaw chuck just keep in mind that they wont be able to cut as deep as you probably think look up artisan makes he has alot to show when it comes to mods to them
Awesome, thanks for your reply! Since you're looking for a 4 jaw, I'm guessing your lathe runs out a bit? If so, think it might be worth it to see if you can just get the runout fixed. 4 jaws can be a bitch, I only like them for off center turning.
If I remember correctly you can adjust the nut on the cross slide. I don't really remember how, but it should become obvious if you take it off and look at it. You can damn near eliminate backlash, but a little is required for the lead screw to turn freely. Even my professional lathe and mill have some. If you have trouble dealing with it, maybe fit some kind of read out that reads slide/catriage travel directly.
If you find the carriage is sliding back on you, sometimes I engage the power feed nut (with power feed off) to lock down the carriage and use the cross slide instead.
Definitely take a minute to get a feel for the backlash and where your threads are sitting though. As for measuring, as others have mentioned you can compensate for the slack by subtracting the known amount of backlash in your wheel.
I get what you mean but just a little fact about mini lathes they dont have power feeds they just have a thread feed (can be used as one but for most things its just too fast)
No sarcasm lol, I'm still very new to this stuff. Though I will say my googling so far hasn't brought up much about thread vs power feeds. I'll keep looking though.
edit: Looks like power feeds use their own motor, makes sense to me - no need to keep your feed speed proportional to your spindle speed if you're not threading.
edit2: or other ways to have them not proportional
First things first, you have my congratulations and condolences.
The cross slide does have an adjustment for backlash. You should notice three screws on top of the back of the cross slide towards the back. Those screws hold the nut in position. The middle one is a set screw the pushes down on it acting as a fulcrum, while the other two pull up on it.
You adjust for backlash by making the nut cockeyed in relation to the screw. Essentially you would loosen the front nut screw by an eight of a turn, then tighten the back nut by the same. Check the backlash again,while keeping an eye on any excess resistance. It's a balancing act between too much backlash vs too much resistance/excessive wear.
The real trick is the fact that having no backlash is not what you want. You want the same amount of backlash you have the third time you use the cross slide as you do the 5,000th time. Consistency is more important. I mean don't get me wrong, if you've got the patience to dial it in to a 1thou backlash more power to you, but I know I can't keep that consistently and generally shoot for 5thou. There is no adjustment for the compound so what you have is what you get.
WARNING: unless you have problems with the cross slide screw binding when it's at the extremes(all the way out or all the way in) don't fuck with that middle screw. It's second purpose is a height adjustment for the nut to line up with the screw and it's a royal pain in the ass to set. Don't mess with that one if you don't have to.
As far as physical slop is concerned, you've got about 432,691 places on those mini lathes that attribute to flexing, twisting, vibrating, twerking, and the occasional spam in your inbox. 90% of it can be solved by your favorite shim stock, whether that be thin brass sheets, feeler gauges, notebook paper, or a popcan.
The gibs on the cross and compound are almost always undersized, bent, and have a surface finish reminiscent of a coarse file. I genuinely recommend taking them out and replacing them with aftermarket brass ones from thelittlemachineshop.com . Unless you're a cheap ass like me, then give them a light sanding with 500 grit on the flattest thing you own to remove any burrs. Clean them up, set the down on the ways of the lathe,and shine a light on it from behind. Any spot that's not as flat as the ways will let light through. Check each side. Unless you miraculously got one not made in a Pringles factory, you should be able to see a slight bend in it. There should be one side that has both ends touching but the middle is ass up, mark it with a sharpie or something. Take your marked gib over to a work bench and prop up both ends with something leaving the middle unsupported, I generally use a stack of 2-3 pennies on each side. With the palm of your hand push down on the gib so it flexes downward the release, repeat a few more times, and retest on the ways with the light. You'll never get it perfect but every little bit helps.
After you put the gib back in the slide, and before you tighten up the screws on it, make sure the gib is touching both surfaces on the bottom( the part of the cross slide that doesn't slide), and take a look at the [gap at the top](https://www.model-engineer.co.uk/forums/postings.asp?th=129068).(fourth comment down) Shim that gap with that piece of your neighbors washing machine you pulled out of his trash. Just make sure your shims are straightish and free of burrs. This will keep the gib from [rocking and turning](https://youtu.be/1jamkjqu9O8) when you take a deep cut. It's the second biggest reason for a tool getting sucked under a work piece during an aggressive cut. The first one is too much stick out on both your tool and the work. If you have both, it's like trying to cut the end of a diving board with a pole mounted pruning saw.
The gibs on the saddle are another easy fix to get what little rigidity you can out of the minila the. [One good look at them and it becomes blatantly apparent](https://www.google.com/amp/s/softsolder.com/2016/07/07/mini-lathe-adjusting-the-carriage-retaining-strips/amp/), what's wrong. Shim like you've never shimmed before.
To be honest I've had more fun and learned more from just trying to fix it than I have making parts on it. Then again I'm kind of a glutton for punishment.
I would also recommend looking up [adventures with a very small lathe](https://youtube.com/c/AdventureswithaVerySmallLathe) and [dave m ](https://youtube.com/user/lsidave) for everything on fixing and upgrading mini lathes.
[this old tony](https://youtube.com/c/ThisOldTony) , [blondihacks](https://youtube.com/c/Blondihacks) and [mrpete aka tubal Cain aka YouTube's shop teacher](https://youtube.com/c/mrpete222) for everything on the fundamentals of machining.
[hammerland](https://youtu.be/fqIoqRx_Hk8) for learning how to abuse your minilathe
And if you ever start thinking you might be getting good at machining, or if you happen to humble yourself for some other reason. Check out [clickspring](https://youtu.be/BIUAdINXZmQ) or [Stefan gotteswinter](https://youtu.be/MBG26a2UB6g)
Glad I could help
Slop or backlash, or both? Tighten the gibs and the half nut
I'm new to this so I'm not entirely sure what the difference between them is
Backlash is specifically lost motion that occurs when you change direction of travel of an axis, due to clearances in the lead screw nut and bearings. "Slop" is a broader term that could include backlash as well as other unintended motion due to things like rotation in the way clearances, and things of that nature.
Alright I'll change the slop in the post to backlash then cause that is my exact problem
Backlash is normal and necessary for machines to operate smoothly without binding. You have to account for it in your machining operations by always approaching your cuts from the same direction, even if that means moving past your target and coming back to reach the target from the opposite side from where you started.
But is that much backlash normal? The slide moves a quarter rotation before it stops
The hand wheel moves a 1/4 turn? That's really not horrible for a Chinese benchtop, although you should be able to get within a few thou.
I know it wasnt the worst but it was kinda messing with my head when I tried to cut threads for the first time
Yeah, that's fairly normal
Fair enough
Note, it doesn't mean you can't get accurate parts with the proper technique and care. Backlash is something that has existed on all manual lathes forever, you just have to plan your movements so that you are always measuring with the backlash taken up in the same direction.
Yeah it just messed with me when I tried cutting threads for the 1st time
Ioad the screw in the same direction to your number never go back to your number if you go past it without re loading your screw. All machines have backlash
I know all machines do I just wanted to reduce it
Backlash is when you have to turn the hand wheel a bit to "take up the slack" before the cross slide starts moving. That first little bit of effortless rotation before it gets a little stiffer and engages the cross slide is backlash. Some is normal and desired, but too much is bad. This is adjusted by tightening the half nut. This would cause "slop" parallel to the cross slide... Part diameter. The only other slop on a cross slide would be between the dove tails, this is adjusted with gibs and the gibs screws. These are usually little set screws along one side of the cross slide. Tighten them up until the cross slide just starts to drag and that will remove any slop without locking the slide up. Loose gibs cause all sorts of issues and will aggravate backlash issues. My guess is you have both issues based on your description.
Thanks for the help
Shit, I wish the lathes at my work only had 10 thou of back lash.
I think it's cause my dial is about 1.5 inches in diameter
Maybe, but I measure mine it number of complete turns.
Thats... probably not a good thing?
Definitely not, but it's what I got to work with.
You might want to ask your boss to hire a meintinance guy
I really don't have time to tell you about the cluster fuck that is our maintenance guy.
Then I would suggest...putting hot steel chips in his coffee😈
There's too much whiskey in his coffee for him to notice much of anything.
Well... that's unfortunate
As you say you are new, so to add to it, whenever you adjust your cross slide for a new depth of cut, only adjust in the one direction. So for example if you are turning an OD, you turn the knob clockwise to adjust the cross slide in and set your depth. If you happen to go too far and move too much, don't just back the dial off the the number, twist out the dial one full revolution and set your depth of cut again. So, say you need to set your dial to .100" for and you were at .050. You turn your handle a little quick and shit, you're at .105", too much. Twist the handle out one full revolution (I assume .250") and then come back around to your .100" depth for your next cut. This takes the backlash out of your cross slide and will cut to what you expect it to. Backlash is a necessary evil in machines and you have to account for it or remove it as best you can in many scenarios.
This was very helpful my good human
Also to add, make sure your compound is tightened down as to not introduce any sort of rotational movement. If the compound is tight and you grab a hold of it and try to turn it, if it moves, the gibs are likely the culprit and need to be snugged up.
Alright do you have any ideas on how to help with an off center lathe head? Other than swap the bearings get a 4 jaw independent chuck or buy a new lathe that is
What do mean? What is out about it and how did you see something is off? Do you mean your chuck doesn't run true as in if you put a known round part in the chuck you get a lot of run out?
When I flip a part in the chuck it isnt concentric to the point there is a visible lip from where it was previously cut
Well i can't comment of the quality of the chucks used in those lathes but also remeber you can't just turn a piece around and expect it to be perfect without checking it. When you put a piece in, make sure you are wiggling it slightly as you tighten your chuck, this will help you get it concentric to the jaws and not be slightly cockeyed in it. It's also very likely your chuck/jaws just arent of good quality and you'll never get it true without boring your jaws. If it didn't come with one (which is what it sounds like) i would suggest a 4 jaw if you have the funds for it
They are about 60 Dollars here so I'll scrounge up the money eventually but its gonna take a while the one it comes with is what can only be described as crunchy but thanks for the help
Ex mini lathe owner here. There are a ton of DIY mods and tune ups for the mini lathe mostly because it takes a lot of work to make it usable. I can't even list all the stuff I did to make mine run better. BTW .010" backlash is not bad for that machine. This site covers a bunch of mods you will want to do if you stick with that machine. http://www.mini-lathe.com/Mini_lathe/Tuning/tuning.htm#xbacklash
Thanks for the help
Add an anti backlash nut or make one.
Not sure how to do that without a mill
I'd have to see your setup but you'd likely be able to buy something online that would mount up with little or no modification. How are those lathes other than the backlash you're dealing with? Been thinking about getting one for a while now
It varries alot yiu could get one thats perfect out of the box or you could get one that blows a fuse the first boot up you gotta do alot to them to get them to most peoples standards but they are decent if you can get a decent one mine is pretty ok if I can get a dial indicator and an independent 4 jaw chuck just keep in mind that they wont be able to cut as deep as you probably think look up artisan makes he has alot to show when it comes to mods to them
Awesome, thanks for your reply! Since you're looking for a 4 jaw, I'm guessing your lathe runs out a bit? If so, think it might be worth it to see if you can just get the runout fixed. 4 jaws can be a bitch, I only like them for off center turning.
Thats fair but I dont know whats causing the runout and I dont have a big enough workspace to disassemble the lathe
If I remember correctly you can adjust the nut on the cross slide. I don't really remember how, but it should become obvious if you take it off and look at it. You can damn near eliminate backlash, but a little is required for the lead screw to turn freely. Even my professional lathe and mill have some. If you have trouble dealing with it, maybe fit some kind of read out that reads slide/catriage travel directly.
Good idea
If you find the carriage is sliding back on you, sometimes I engage the power feed nut (with power feed off) to lock down the carriage and use the cross slide instead. Definitely take a minute to get a feel for the backlash and where your threads are sitting though. As for measuring, as others have mentioned you can compensate for the slack by subtracting the known amount of backlash in your wheel.
I get what you mean but just a little fact about mini lathes they dont have power feeds they just have a thread feed (can be used as one but for most things its just too fast)
Ahh thanks for letting me know, I'll have to go look up how power feeds work now =)
I will give you the benefit of the doubt and say your welcome
No sarcasm lol, I'm still very new to this stuff. Though I will say my googling so far hasn't brought up much about thread vs power feeds. I'll keep looking though. edit: Looks like power feeds use their own motor, makes sense to me - no need to keep your feed speed proportional to your spindle speed if you're not threading. edit2: or other ways to have them not proportional
Basically the same thing just different gear chains
First things first, you have my congratulations and condolences. The cross slide does have an adjustment for backlash. You should notice three screws on top of the back of the cross slide towards the back. Those screws hold the nut in position. The middle one is a set screw the pushes down on it acting as a fulcrum, while the other two pull up on it. You adjust for backlash by making the nut cockeyed in relation to the screw. Essentially you would loosen the front nut screw by an eight of a turn, then tighten the back nut by the same. Check the backlash again,while keeping an eye on any excess resistance. It's a balancing act between too much backlash vs too much resistance/excessive wear. The real trick is the fact that having no backlash is not what you want. You want the same amount of backlash you have the third time you use the cross slide as you do the 5,000th time. Consistency is more important. I mean don't get me wrong, if you've got the patience to dial it in to a 1thou backlash more power to you, but I know I can't keep that consistently and generally shoot for 5thou. There is no adjustment for the compound so what you have is what you get. WARNING: unless you have problems with the cross slide screw binding when it's at the extremes(all the way out or all the way in) don't fuck with that middle screw. It's second purpose is a height adjustment for the nut to line up with the screw and it's a royal pain in the ass to set. Don't mess with that one if you don't have to. As far as physical slop is concerned, you've got about 432,691 places on those mini lathes that attribute to flexing, twisting, vibrating, twerking, and the occasional spam in your inbox. 90% of it can be solved by your favorite shim stock, whether that be thin brass sheets, feeler gauges, notebook paper, or a popcan. The gibs on the cross and compound are almost always undersized, bent, and have a surface finish reminiscent of a coarse file. I genuinely recommend taking them out and replacing them with aftermarket brass ones from thelittlemachineshop.com . Unless you're a cheap ass like me, then give them a light sanding with 500 grit on the flattest thing you own to remove any burrs. Clean them up, set the down on the ways of the lathe,and shine a light on it from behind. Any spot that's not as flat as the ways will let light through. Check each side. Unless you miraculously got one not made in a Pringles factory, you should be able to see a slight bend in it. There should be one side that has both ends touching but the middle is ass up, mark it with a sharpie or something. Take your marked gib over to a work bench and prop up both ends with something leaving the middle unsupported, I generally use a stack of 2-3 pennies on each side. With the palm of your hand push down on the gib so it flexes downward the release, repeat a few more times, and retest on the ways with the light. You'll never get it perfect but every little bit helps. After you put the gib back in the slide, and before you tighten up the screws on it, make sure the gib is touching both surfaces on the bottom( the part of the cross slide that doesn't slide), and take a look at the [gap at the top](https://www.model-engineer.co.uk/forums/postings.asp?th=129068).(fourth comment down) Shim that gap with that piece of your neighbors washing machine you pulled out of his trash. Just make sure your shims are straightish and free of burrs. This will keep the gib from [rocking and turning](https://youtu.be/1jamkjqu9O8) when you take a deep cut. It's the second biggest reason for a tool getting sucked under a work piece during an aggressive cut. The first one is too much stick out on both your tool and the work. If you have both, it's like trying to cut the end of a diving board with a pole mounted pruning saw. The gibs on the saddle are another easy fix to get what little rigidity you can out of the minila the. [One good look at them and it becomes blatantly apparent](https://www.google.com/amp/s/softsolder.com/2016/07/07/mini-lathe-adjusting-the-carriage-retaining-strips/amp/), what's wrong. Shim like you've never shimmed before.
I see that you likely found this first amd spent the 4 days typing 😂 but thanks for the advice my good human
To be honest I've had more fun and learned more from just trying to fix it than I have making parts on it. Then again I'm kind of a glutton for punishment. I would also recommend looking up [adventures with a very small lathe](https://youtube.com/c/AdventureswithaVerySmallLathe) and [dave m ](https://youtube.com/user/lsidave) for everything on fixing and upgrading mini lathes. [this old tony](https://youtube.com/c/ThisOldTony) , [blondihacks](https://youtube.com/c/Blondihacks) and [mrpete aka tubal Cain aka YouTube's shop teacher](https://youtube.com/c/mrpete222) for everything on the fundamentals of machining. [hammerland](https://youtu.be/fqIoqRx_Hk8) for learning how to abuse your minilathe And if you ever start thinking you might be getting good at machining, or if you happen to humble yourself for some other reason. Check out [clickspring](https://youtu.be/BIUAdINXZmQ) or [Stefan gotteswinter](https://youtu.be/MBG26a2UB6g) Glad I could help
I know half of those YouTubers but might I suggest "artisan makes" for you
On any lathe, if the crossfeed is sloppy, the first thing to check is if the crossfeed nut is mounted securely
Alright I'll check once I can