Unless your lathe is brand new and super rigid, you're always going to get taper and out of round in your parts. The tests you did help to define the limits of the accuracy you can expect. Regards, Preso
G'day Rusti and nice work. I remember when I first started using my Colchester late. I was lazy and didn't level it. It was machining an ice cream cone when boring. Cheers, Aaron.👍
Happy days Michel 🎉 seems bob on to me buddy, there's always a little learning, how to get the best out of your equipment, thanks for sharing, best wishes to you and yours Ralfy
I had the same problem with my Harrison L6-12. After checking the ways, the perpendicularity of the chuck and the jaws, I finally removed the gap under the chuck. And this solves the taper problem.
Very interesting. I have not really thought about it in depth like you, but think I might have the same problem on my lathe. Up to now it didn’t give me trouble. Thanks. Brilliant video.
Thank you for taking the time to share your experiences with use. I'm always glad to see what you are up to. BTW, would you consider giving us a brief tour of your shop sometime? I'd really like to see a closeup of your grinding center. Thanks again. Randall in Kentucky USA.
That’s really good actually, most lathes this size are either beat up pretty bad or new and too expensive. You Should take pride in the setup and accuracy of your machine. That’s a lot or work getting one setup properly and cutting that good. 👍🏻
My JFMT has the same wear on the inner way . The rest are perfect . I will probably grind just that inner surface & that will bring it back to near new condition . 👍
As you may have noticed I have a bit of a taper turning problem on my lathe and it's mostly in the last 10-15mm before the chuck, I tried hard to overcome it, but couldn't, so I just learned to live with it.
Well, your lathe turns more parallel than mine! I think mine has 0.1mm of wear vertically on the bed and it turns consistent undulations in a part, so much so that my final cuts are made with " manual CNC" adjustments, followed by abrasive. The cure in my case is simple, spend money! Either regrind the bed or change lathes. In the meantime, while I'm saving my pennies (cents I guess in your case!), I'll put up with it!
That's pretty alright. With no tailstock support, the taper further out on a heavy cut could be some flex in the piece, or more likely a little bit of play in the headstock bearings. If you don't want the soviet lathe, I could swap it for a plain cutting schaublin clone :)
Cutting cones is usually due to a twisted bed which can be shimmed to be level. The best way to test is get a longish bar say 3-400mm and turn the middle narrow a bit then make a pass each end at the same setting then the tool doesn’t heat up. Measure each end and then shim the bed till it cut Parrellel. Having said all this my lathe is 0.06mm out and it’s fine
Your bed could have a slight dip, maybe mine too but more likely my tapers are caused by a. deflection when turning thin bar stock or b. Tailstock alignment issue.
Hi Michael Nice video. I had simillar problem on one lathe that has removable gap. Gap piece was not properly installed. Surface below gap had ding and filth. One queestion about Celtic, does it have cluches for forward/reverse or it is direct start lathe? All parts of video where Celtic run are accelerated, I would like to see it and hear it in normal "mode". On my parts we tend to lean on German/Italian/Swiss machines, Celtic looks nice but was not available here, same as Somua.
@@Rustinox Thanks for the answer. I enjoy your videos and find them inspiring. First time i have touched lathe was in 2012, now i have 3. For me lathes and milling machines are hobby within my work. My work finances my hobby, and my hobby compliments my work.
I often wonder what a new high quality machine would feel like using. I started with a small Craftsman lathe with a 4” chuck. Replaced it with a new 14x40 Chinese machine, and initially I was all smiles, and then started finding its errors, most notably the tailstock is not repeatable. On examining the scraping of the slide under it, it looks like a rodent chewed it out.
It’s not clear to me how you ruled out that the bar itself was not deflecting. With lighter cuts, clearly it would deflect less, as your testing showed. While I don’t disagree that bed wear could cause this, I would first rule out part deflection ( or spindle bearing wear, as another commenter mentioned). Since you don’t want to use tail support, perhaps a follow rest could shed more light on it, by limiting part deflection?
A good result finding that your lathe is working fairly accurately Michel. At the beginning I disagree with you in your method though. Even though you up sized the boring bar any discrepancy could normally be put down to boring bar flexing. That in itself does not test the machine. The only result is confirming the tooling Not the lathe to be the cause of any deviation in dimension. However after changing the boring bar to a larger one you now have identified some very small amount of wear in the machine even though it shows up to be around on hundredth of a millimetre which is very good for a lathe of that age.
@@Rustinox Absolutely right! The idea that boring bar flex can introduce a taper is a very common one, but it makes no physical sense at all. Deflection is a function of rigidity and tool pressure, not depth.
Nice work Michel, a home lathe that is only a file or abrasive away from spot on is where we want to be. Enjoyed the visit, take care and cheers!
It's good for me.
What I like about your channel is: you never know what is coming and it never disappoints! Thank You 👍
Because I don't know myself. I start filming and see what happens.
@@Rustinox 👍
Unless your lathe is brand new and super rigid, you're always going to get taper and out of round in your parts. The tests you did help to define the limits of the accuracy you can expect.
Regards, Preso
Knowing the machine is very important.
Thanks Michel. Always a pleasure 👍
All in all pretty good 👍👍👍
It is.
A very well thought out test. I don’t think you could complain at the end result. You must be happy Michel. Thanks for sharing. Cheers Nobby
Indeed, I'm happy with it.
Very fine notes. Once again, I learned a lot. A very useful and sympathetic performance!
Thanks.
G'day Rusti and nice work. I remember when I first started using my Colchester late. I was lazy and didn't level it. It was machining an ice cream cone when boring. Cheers, Aaron.👍
Making ice cream cones isn't maybe not the first purpose of a lathe :)
Hi Michel. You cannot knock that result. Almost perfect.
Steve.
Almost...
Very excellent. Love the thought process - enjoyed watching you run that lovely lathe.
Thanks Stuart.
Happy days Michel 🎉 seems bob on to me buddy, there's always a little learning, how to get the best out of your equipment, thanks for sharing, best wishes to you and yours Ralfy
Happy days indeed. Thanks Ralfy.
I had the same problem with my Harrison L6-12. After checking the ways, the perpendicularity of the chuck and the jaws, I finally removed the gap under the chuck. And this solves the taper problem.
Nice. Good to go.
Hi Michel, an interesting exercise and very well reasoned. Its a very solid lathe.
Have a great weekend!!
Thanks.
Well tested Rustinox. As long as you can work with the accuracy it provides it's a winner for a freebee. Cheers Tony
It sure is.
seems like a good result,,, we all use old machines of some sort and must expect minor problems. cheers👍👍
Indeed, we do.
Very interesting. I have not really thought about it in depth like you, but think I might have the same problem on my lathe. Up to now it didn’t give me trouble.
Thanks. Brilliant video.
Thanks. If it works, it works :)
Interesting video,Michel.Thank you.
Thanks.
Good testing and diagnostics Michele.
Thanks.
Thank you for taking the time to share your experiences with use. I'm always glad to see what you are up to. BTW, would you consider giving us a brief tour of your shop sometime? I'd really like to see a closeup of your grinding center. Thanks again. Randall in Kentucky USA.
Yes I second that Michel.
One day maybe. But the grinding corner is nothing special.
It’s helps to know how your lathe cuts . Sounds like yours is in great shape . Thanks Rusty
Good for me.
Thanks , something new to learn
With a bit of thinking :)
G'day Rusty. Excellent Tutorial. Well done ✔️ 😊
Thanks.
Hi mate in Australia matty and I go to truck repair shops ang get the old truck brake cams good steel for lathe material 👍
Indeed, these "S" axis are good stuff.
That’s really good actually, most lathes this size are either beat up pretty bad or new and too expensive. You Should take pride in the setup and accuracy of your machine. That’s a lot or work getting one setup properly and cutting that good. 👍🏻
My lathe is indeed beaten up. But it works.
My JFMT has the same wear on the inner way . The rest are perfect . I will probably grind just that inner surface & that will bring it back to near new condition . 👍
Go for it.
As you may have noticed I have a bit of a taper turning problem on my lathe and it's mostly in the last 10-15mm before the chuck, I tried hard to overcome it, but couldn't, so I just learned to live with it.
A final touch on the part with some sand paper and you're good.
@@Rustinox Exactly
Well, your lathe turns more parallel than mine! I think mine has 0.1mm of wear vertically on the bed and it turns consistent undulations in a part, so much so that my final cuts are made with " manual CNC" adjustments, followed by abrasive.
The cure in my case is simple, spend money! Either regrind the bed or change lathes.
In the meantime, while I'm saving my pennies (cents I guess in your case!), I'll put up with it!
Indeed, cents. But I'm sure it is usable as is.
That's pretty alright. With no tailstock support, the taper further out on a heavy cut could be some flex in the piece, or more likely a little bit of play in the headstock bearings.
If you don't want the soviet lathe, I could swap it for a plain cutting schaublin clone :)
Indeed, the bearings need some attantion.
Great info!
You missed pressing record thats ok i will just close my eyes and replay it on my imaginationtron 600.
Wow Michael that piston looks good.
Imagination, what should we do without it :)
Cutting cones is usually due to a twisted bed which can be shimmed to be level. The best way to test is get a longish bar say 3-400mm and turn the middle narrow a bit then make a pass each end at the same setting then the tool doesn’t heat up. Measure each end and then shim the bed till it cut Parrellel. Having said all this my lathe is 0.06mm out and it’s fine
I know the drill. But I wanted to test it without til support.
Once again thank you for the content Good onya
My pleasure.
And its paid for. 😊
Absolutely.
Your bed could have a slight dip, maybe mine too but more likely my tapers are caused by a. deflection when turning thin bar stock or b. Tailstock alignment issue.
A test will tell you all about it.
Brilliant 👍👍😎👍👍
Thanks.
Hi Michael
Nice video. I had simillar problem on one lathe that has removable gap. Gap piece was not properly installed. Surface below gap had ding and filth.
One queestion about Celtic, does it have cluches for forward/reverse or it is direct start lathe? All parts of video where Celtic run are accelerated, I would like to see it and hear it in normal "mode".
On my parts we tend to lean on German/Italian/Swiss machines, Celtic looks nice but was not available here, same as Somua.
There is no clutch in the celtic. It's a two speed motor.
@@Rustinox Thanks for the answer. I enjoy your videos and find them inspiring. First time i have touched lathe was in 2012, now i have 3.
For me lathes and milling machines are hobby within my work. My work finances my hobby, and my hobby compliments my work.
I often wonder what a new high quality machine would feel like using. I started with a small Craftsman lathe with a 4” chuck. Replaced it with a new 14x40 Chinese machine, and initially I was all smiles, and then started finding its errors, most notably the tailstock is not repeatable. On examining the scraping of the slide under it, it looks like a rodent chewed it out.
I think whatever lathe will do. Just get used to it.
It’s not clear to me how you ruled out that the bar itself was not deflecting. With lighter cuts, clearly it would deflect less, as your testing showed. While I don’t disagree that bed wear could cause this, I would first rule out part deflection ( or spindle bearing wear, as another commenter mentioned). Since you don’t want to use tail support, perhaps a follow rest could shed more light on it, by limiting part deflection?
The deflection of this 40 mm during a light cut is so minimal, I can't even mesure it.
A good result finding that your lathe is working fairly accurately Michel. At the beginning I disagree with you in your method though. Even though you up sized the boring bar any discrepancy could normally be put down to boring bar flexing. That in itself does not test the machine. The only result is confirming the tooling Not the lathe to be the cause of any deviation in dimension. However after changing the boring bar to a larger one you now have identified some very small amount of wear in the machine even though it shows up to be around on hundredth of a millimetre which is very good for a lathe of that age.
The flexing of the boring bar is consistant over the whole cut, if the tepth of cut is the same over the whole part.
@@Rustinox Absolutely right! The idea that boring bar flex can introduce a taper is a very common one, but it makes no physical sense at all. Deflection is a function of rigidity and tool pressure, not depth.
👍😎
Thanks.
Close, but close only counts in "Horseshoes and Hand-grenades" !!!
Good to know :)
Always make a bevel when (test) fitting such parts.
That could help.
Sooooooo, it works for what you need; at this time. Enjoyed! Thanks.
Good for me.