- Jun 14, 2021
- Reaction score
- Manchester England
Great advise Ken I will take it all onboardThis diagram may help?
And on a small lathe like this (similar to mine) I find it best to always use SHARP tools, - e.g. HSS tools or Carbide inserts for ALUMINIUM (Not cheaper ones for steel!).
The Carbide inserts for steel that I have experienced always need to be "honed to sharp for best work. The small lathe just does not have the torque and STIFFNESS to handle the loads that are required to make the carbide inserts for steel work properly.
So, I use the HSS tools and keep them sharp.
I rarely take more than a 0.020" cut - as the swarf can be too strong to break into chips - but usually many cuts of ~0.010 are good for this size of lathe. HEAVY cuts can be made, but the whole thing starts to twist under heavier loads, so you lose PRECISION.
This is a hobby, so "manufacturing production" speeds and feeds are not suited to "Hobby" lathes. If you need big speeds and feeds then spend 10 times more on a heavy industrial machine that is designed to do the work.
But if making precision models, take it slowly, carefully, and enjoy the whole experience. - It works for me. Life is not a race: the only race is "the Human race"! Relax and feel good about your work, and you'll enjoy it.
Centre tools with a rule - as above - then cut across an end of bar and the cutting centre will show you how accurately you have set the tool. - A centre "pip" means the tool is a fraction too low, but a pip that gets "pushed-off" by the tool means the tool is too high. - High is worse than low for anything as the tool will not cut properly but need "HIGH LOADS" to make it work. Too low, and there is a chance of the tool digging-in... but keep the tool end close to the tool post (a long whange hanging out is just bad practice! - It needs to be short and stiff for good work). - I never extend the cutting end of the tool more than 2 x tool-bar thicknesses from the tool post. - except where there is no other way, such as when boring. I.E. a 1/2" square tool MUST NOT extend more than 1" from the tool post support. But a 1/4" base beneath a carbide tip at the end of a 1/2" bar really needs more support, for the heavy cuts it is designed for. Which is one reason a 1/2" of HSS works so much better.
The STIFFNESS of a 1/4" bar is 1/8th of the STIFFNESS of a 1/2" bar. So, the tool is just poorly supported and will vibrate under cutting loads, at the natural frequency of the stiffness of the bar. When I use a Carbide tipped tool, there is only the MINIMUM of tool extending from the tool-post - and I sharpen with a diamond hone to give it the best chance of doing the cutting (shearing of metal) that I want it to do.
Enjoy making precision parts - not swarf and scrap!