I'm not sure about those specific rails and linear bearings but typically, you don't use grease on machine tool. I believe this has to do with the grease turning into a slurry from chips and dust. I think it may be best to stick to oil. Hydrolytic oil is what I use in mine. It has the advantage of easy plumbing for automatic oilers.
Oh my, okay I’ll look into that, hopefully if this is badly wrong I could just pump oil through to remove it lol. I do plan on having ways covers though, so hopefully that will help too
When you’re cutting and you feel your blade start to pinch, just fully back out of the cut and run the saw through again. That will recut whatever deflected inward. Might have to do it several times but it should cut fine.
Good to hear from you again Bob! True, I should probably strip the paint on all the pieces and then heat them all honestly. I doubt I’d end up really committing to doing it each time I use a piece otherwise hahaha
Great progress! In engineering, everything is a spring, and the softness of the complete system is softer than the softest spring in the chain (Same math as resisters in parallel). That Z motor mount looks very soft in bending. Put a clock on it and see how much it flexes. You have made a really rigid bed, would be shame to negate some of that advantage to a single components compromises. Good think is you will soon have a lathe to make replacement parts for itself. Home shop machining is a closed hobby.
That’s very fair, and actually something I was thinking about a little bit but Id love to see what you think about this reasoning So my Z stepper has a pulley to my main leadscrew. The main forces the assembly will take will be tension force in the direction of the belt, pulling from the stepper pulley towards the leadscrew pulley. So the tension force is opposed by the force of my carriage bolt on the side of the lathe. The main deflection I see would be a deflection from moment force about the vertical axis. There is about .75in in the z direction between the carriage bolt and the stepper pulley. My thinking is that even if the stepper is at a full load of 4Nm torque, that would be a negligible deflection, although to be fair I didn’t do the math. You raise a really good point though about springs, I remember doing vibrations in college and thought that was such a cool concept. Probably worth remaking the stepper tensioner later regardless, at least to try to keep reducing deflections throughout the machine
@@robertsteinwandel6658 Put a clock on it, and take roughing cuts, and you will soon see :) Those really high performance industrial machine tools tend to have a stifness budget of about 20N/µm of deflection. You have to have everything really stiff to get close to that. Thin leadscrews, poor screw bearings, undersized belts etc all eat that up fast.
@@RotarySMP lol yeah, how about if I have issues with all of those things hahaha. I do have my Ballscrews so they would generally be in tension during a cut which I figure will help (I’ll need better Ballscrews eventually). I’ll need to actually bolt everything down and check the deflections soon, thanks for the stiffness number though that’s great, I really didn’t have a good conclusive number before. I would assume that 20N/um would be out of my reach without a lot of rework, but it’ll be interesting to see what I could get to!
@@robertsteinwandel6658 DId you see my Minilathe episode where I put a clock between spindle and tailstock and twisted the bed with bare hands. I think the minilathe would have a "stiffness" of about 0.1N/µm or worse. Kind of like cooked spaghetti. You are going to worlds ahead of that. I think 20N/µm is the sort of stiffness a new high end machine like a Mazak achieves. I think the bigger practical issue you will have is keeping swarf out of that belt. ;) Why didn't you put the drive down at the clean end?
@@RotarySMP I did! That was the vid I believe where you attached it to the big steel plate for added rigidity right? I’ll keep those as benchmarks then, somewhere between .1N/um and 20, hopefully closer to 20 haha I only put it there so I’m putting the leadscrew in tension during a cut towards the headstock, I figure it would have less axial deflection in tension since it wouldn’t want to bow like it would in compression
I'd use an angle grinder to cut those pieces of angle that want to close up. Just don't allow the blade to sink into the material. This means you essentially score the work along your cutting line never allowing your blade to completely sink through the cut until it's very thin. It requires multiple passes.
4:40 - The perfect tool is a metal cutting bandsaw, I have seen people making their own. Need to make/buy a large length bandsaw so that it can cut large and tick metal pieces. That machine is super scary and dangerous, would advice to buy one since a lot of safety for the user needs to be well thought of if making one. A much better and safer option is to use a high amp plasma cutter, it will cut through thick metal quick and easy.
Absolutely, a horizontal bandsaw is on my list, although I don’t really have space for it right now is my biggest issue. The circular saw I think is quite safe when it’s used for metal it’s made to cut (around 1/8th in to 3/4in) but I do agree it’s probably not great to use it for some of these other cuts. Hopefully before too long I’ll be able to get the bandsaw and then the problem will resolve itself
You should have installed crosslide top plate first before drilling for ball screw Mounts !!! This way you could have maintained lowest disalignment possible.
I actually have enough play in the holes where I can align it as accurately as possible after the fact, or at least I believe that’s what you’re referring to? The alignment between my cross slide rails and cross slide ballscrew correct?
Hi Robert - can you add a contact email to your About page? We're discussing your lathe build on our homemade tools forum. Sometimes when I post a link in YT comments it doesn't come through, but I can email you a link to the discussion.
I saw actually! Adding the email now. TH-cam studio linked me to it lol. I actually was really interested in learning more about the comment regarding the spindle length. It sounded like there was some reason why I would need a longer spindle with more distance between bearings, but I don’t understand why exactly? Assuming the spindle is taking lateral force at the front end, the spindle would be a lever “pivoting” around the front bearing right? So to me so long as the distance between front and rear bearings is reasonable, the mechanical advantage of the force acting on the rear bearing would be about 1:1. Is there something I was missing with that?
@@robertsteinwandel6658 Thanks; I just got your account set up and sent you an email. You can go ahead and post your point about the spindle length and I'm sure you'll get a detailed reply.
Great video. I’m enjoying following this project.
Thanks a ton! Really enjoying makin the videos!
4:30 My experience is that if you want to get rid of tension in steel, you need to anneal it. Even hot rolled steel need it.
I'm not sure about those specific rails and linear bearings but typically, you don't use grease on machine tool. I believe this has to do with the grease turning into a slurry from chips and dust. I think it may be best to stick to oil. Hydrolytic oil is what I use in mine. It has the advantage of easy plumbing for automatic oilers.
Oh my, okay I’ll look into that, hopefully if this is badly wrong I could just pump oil through to remove it lol. I do plan on having ways covers though, so hopefully that will help too
When you’re cutting and you feel your blade start to pinch, just fully back out of the cut and run the saw through again. That will recut whatever deflected inward. Might have to do it several times but it should cut fine.
That is the great gear you have in your shop 😊
Thanks!!
You could heat up the angle iron to relieve the tension using a torch.
Good to hear from you again Bob!
True, I should probably strip the paint on all the pieces and then heat them all honestly. I doubt I’d end up really committing to doing it each time I use a piece otherwise hahaha
Great progress!
In engineering, everything is a spring, and the softness of the complete system is softer than the softest spring in the chain (Same math as resisters in parallel).
That Z motor mount looks very soft in bending. Put a clock on it and see how much it flexes. You have made a really rigid bed, would be shame to negate some of that advantage to a single components compromises.
Good think is you will soon have a lathe to make replacement parts for itself. Home shop machining is a closed hobby.
That’s very fair, and actually something I was thinking about a little bit but Id love to see what you think about this reasoning
So my Z stepper has a pulley to my main leadscrew. The main forces the assembly will take will be tension force in the direction of the belt, pulling from the stepper pulley towards the leadscrew pulley. So the tension force is opposed by the force of my carriage bolt on the side of the lathe. The main deflection I see would be a deflection from moment force about the vertical axis. There is about .75in in the z direction between the carriage bolt and the stepper pulley. My thinking is that even if the stepper is at a full load of 4Nm torque, that would be a negligible deflection, although to be fair I didn’t do the math.
You raise a really good point though about springs, I remember doing vibrations in college and thought that was such a cool concept. Probably worth remaking the stepper tensioner later regardless, at least to try to keep reducing deflections throughout the machine
@@robertsteinwandel6658 Put a clock on it, and take roughing cuts, and you will soon see :)
Those really high performance industrial machine tools tend to have a stifness budget of about 20N/µm of deflection. You have to have everything really stiff to get close to that. Thin leadscrews, poor screw bearings, undersized belts etc all eat that up fast.
@@RotarySMP lol yeah, how about if I have issues with all of those things hahaha. I do have my Ballscrews so they would generally be in tension during a cut which I figure will help (I’ll need better Ballscrews eventually).
I’ll need to actually bolt everything down and check the deflections soon, thanks for the stiffness number though that’s great, I really didn’t have a good conclusive number before. I would assume that 20N/um would be out of my reach without a lot of rework, but it’ll be interesting to see what I could get to!
@@robertsteinwandel6658 DId you see my Minilathe episode where I put a clock between spindle and tailstock and twisted the bed with bare hands. I think the minilathe would have a "stiffness" of about 0.1N/µm or worse. Kind of like cooked spaghetti. You are going to worlds ahead of that. I think 20N/µm is the sort of stiffness a new high end machine like a Mazak achieves.
I think the bigger practical issue you will have is keeping swarf out of that belt. ;) Why didn't you put the drive down at the clean end?
@@RotarySMP I did! That was the vid I believe where you attached it to the big steel plate for added rigidity right?
I’ll keep those as benchmarks then, somewhere between .1N/um and 20, hopefully closer to 20 haha
I only put it there so I’m putting the leadscrew in tension during a cut towards the headstock, I figure it would have less axial deflection in tension since it wouldn’t want to bow like it would in compression
I want to follow this build... Looking really good so far 😎💥👌🏻
Thank you!
I'd use an angle grinder to cut those pieces of angle that want to close up. Just don't allow the blade to sink into the material. This means you essentially score the work along your cutting line never allowing your blade to completely sink through the cut until it's very thin. It requires multiple passes.
That’s a great idea, thanks!
I’ve heard that makes the blade last longer too which would be nice
4:40 - The perfect tool is a metal cutting bandsaw, I have seen people making their own. Need to make/buy a large length bandsaw so that it can cut large and tick metal pieces. That machine is super scary and dangerous, would advice to buy one since a lot of safety for the user needs to be well thought of if making one. A much better and safer option is to use a high amp plasma cutter, it will cut through thick metal quick and easy.
Absolutely, a horizontal bandsaw is on my list, although I don’t really have space for it right now is my biggest issue. The circular saw I think is quite safe when it’s used for metal it’s made to cut (around 1/8th in to 3/4in) but I do agree it’s probably not great to use it for some of these other cuts. Hopefully before too long I’ll be able to get the bandsaw and then the problem will resolve itself
Cool job
Thank you!
You should have installed crosslide top plate first before drilling for ball screw Mounts !!! This way you could have maintained lowest disalignment possible.
I actually have enough play in the holes where I can align it as accurately as possible after the fact, or at least I believe that’s what you’re referring to? The alignment between my cross slide rails and cross slide ballscrew correct?
Hi Robert - can you add a contact email to your About page? We're discussing your lathe build on our homemade tools forum. Sometimes when I post a link in YT comments it doesn't come through, but I can email you a link to the discussion.
I saw actually! Adding the email now. TH-cam studio linked me to it lol. I actually was really interested in learning more about the comment regarding the spindle length. It sounded like there was some reason why I would need a longer spindle with more distance between bearings, but I don’t understand why exactly? Assuming the spindle is taking lateral force at the front end, the spindle would be a lever “pivoting” around the front bearing right? So to me so long as the distance between front and rear bearings is reasonable, the mechanical advantage of the force acting on the rear bearing would be about 1:1. Is there something I was missing with that?
@@robertsteinwandel6658 Thanks; I just got your account set up and sent you an email. You can go ahead and post your point about the spindle length and I'm sure you'll get a detailed reply.
Watch your fingers and hands bud. Clamps for sure if there’s razor wire. Watch your drill speed
I need to get some bolts to clamp my vice to my drill press table honestly, it would help a ton