First lathe
- Thread starter nana1962409
- Start date
Wondering if those that have some lathe experience could give their opinions. I have been playing around on the lathe and still can’t get a good surface finish on the piece of steel I’m turning. I believe it is 1018 cold rolled. I have tried all different speeds and feeds and insert tooling and hss tooling with all sorts of radius on the hhs bits. Just to try something different I grabbed a grade 8 bolt and turned it at the same speed as the bar stock and it looks great. So I’m wondering is it just the nature of the steel I’m trying to turn that it doesn’t come out like I think it should? I could just hit it with emery cloth to finish it but just was curious if maybe there is something I’m missing that I can’t get the finish good on this?
1018 is usually so soft that it is difficult to get a good finish. Alot depends on your cutting tool/insert. A larger radius gives a better finish but can chatter. Run it as fast as you can with a .031 radius insert, about .004 thousandths feed rate. Play with feeds and speeds until it looks good. Dont try to take tiny cuts either, leave some meat for the finish pass as you can. Machine horsepower comes into play then.
Heddrik here are some pictures of the cutters I tried. I find I am getting better results with the hss ones on this steel. My inserts are a .031 radius on them. I am running the lathe at full speed and my feed rate is as slow as I can go with my gear setup at .0013. Maybe part of the issue is taking little cuts vs the larger you suggested.
Some times tool steel works better than carbide, esp on aluminum. Take a deeper cut and maybe increase the feed . If you can find an insert that has a positive rake it should work better. I don t have pictures to show you. I may some in my toolbox in storage. 1018 just sucks for a finish. If you like, try and find some 12L14, it's soft but machines better and its not real expensive I think. I have polished a lot of 1018 in my time with sandpaper and scotch brite to get a nice finish.
The small lathes don't have the mass or strength in the ways that bigger lathes have, that causes small vibrations throught the ways of the lathe while cutting, making it more dfficult to get a smooth finish. I went thru this same senario with a small lathe similiar to yours. After working with a group of tool makers in machine shop they confirmed this, my solution was to step up to a 14x 30 Clausing. Problem solved.
Dave I’m sure your right and I know my bench top style lathe lacks the rigidity of a larger floor type of lathe. For now I’m gonna using what I got and figure out how to work around the issues of this lathe. 64ss409 yes my lathe does have the flat ways.
I did try the heavier cut and it still didn’t turn out much better so I decided to just use a metal that cuts better and am happy with my project. I used a grade 8 bolt for stock and made a crank pinning tool for work so I don’t have to go find the shop one anymore.
I did try the heavier cut and it still didn’t turn out much better so I decided to just use a metal that cuts better and am happy with my project. I used a grade 8 bolt for stock and made a crank pinning tool for work so I don’t have to go find the shop one anymore.
Have you ever seen them wrap a band around a drum or a clamp for a rotor on a brake lathe. Turning down the cast will cause vibration due to it being more porous. If you put a grade two bolt in and turn it down compared to the grade 8 you’ll see that the grade 8 will have a smoother finish. The larger head mass on a big lathe will also cut down on the vibration. To a point speed is your friend. It’s my experience anyway.
Thanks for the interesting reading - I'm learning a lot from these replies. I also never used a lathe but got my late grandfather's South Bend model C9 this summer. It has a plate from WWII riveted on it that states: THIS MACHINE CONFORMS TO THE ORDERS OF THE WAR PRODUCTION BOARD. So far I've turned some brass fittings into connectors for new cables for his old arc welder. I haven't tried the cables because I don't have 240 volt power in the garage yet. Now I'm making my own exhaust pipe expander by turning the ends of concentric pipes and turning two steel bushings into opposing cones. Yes, I have to remind myself to not leave the key in the chuck. Did that once so far and it landed harmlessly on the floor, but next time I might not be so lucky.
