Help: Chatter on lathe, what's wrong

[Chiptosser]

Shaun Free-

This is very important, NEVER part pieces between centers, its not pretty if you try.

Don't say this, This is commonly done, maybe not for your use but it is done.

 

[Cogsy]

Shaun Free-

This is very important, NEVER part pieces between centers, its not pretty if you try.

Don't say this, This is commonly done, maybe not for your use but it is done.

It's certainly not common in the home shop and can be a very dangerous practice. Personally, I would NEVER recommend such a practice to someone just starting in learning to machine, and personally I'd never even consider completely parting off between centres at all - too many bad things can happen. I think Shaun was giving very good advice to someone just starting out.

 

[XD351]

Better to set up a steady to support the part rather than between centres when you are parting off from a long piece

 

[bluejets]

I have just started practicing on my Grizzly 9 x 22 lathe and get chatter when I'm turning, but not facing. In the photo I have a 2" steel cylinder, the end is good when faceing, but shows chatter when I tried to use a parting tool, also marks from the tool bit (the picture shows the second tool bit I tried). What things can I try to stop the chatter.

Details, I have not done anything else on this lathe, so it's essentially brand new.
the cylinder is about 2" x 6", facing on the end went fine. When turning the chatter stops about 1.5" from the chuck and runs fine (what you see is the results of a frustrated newbie cleaning up with a file). With the parting and cutter tools, I tried a little above and below center but didn't notice any change. Oh, I varied speeds from 100 rpm to 450 rpm.

One last tidbit, I wonder if I damaged the "power head"View attachment 110696 . My first attempt was a total goof. I started up the lathe with this steel but the chuck was not tight. After I got it stopped, the chuck jaws were bent after the cylinder whacked the tool post. I replaced the chuck with a new replacement from Grizzly, checked level, re-adjusted gibs and inspected the tool post.

 

[Wizard69]

It is important to understand the dangers in excessive stickout from the chuck. That can be a danger. Id suggest getting a book on how to run a lathe.

Beyond that the Asian import lathes generally are not ready to run out of the box. I'd go into details but seem to be having significant video driver issues at the moment. there are however threads and youtube videos on the basics of starting up one of these lathes.

Thanks for the replies.
Hum, I did not think the piece was too long, but I suppose I should start smaller. I didn't hear any comments that something is wrong with the lathe, so that's a plus.

 

[larryg]

Another thing to watch is your cut size. If you have a broad flat end on your cutter the chips will be wide and thin like a ribbon. This takes a lot of HP and rigidity. A small tip that produces a chip that is like a fine wire requires a lot less stress on the machine.

If your cutter is a bit above center then if it flexes down it will move into the work piece and cut deeper exasperating your troubles. If your not on center then be a bit below so that the cutter will move away from the material and lighten the cut.

Also understand that the machine twists and bends and absorbs energy while cutting. If it can release this energy and spring back it does. If it does this on a regular time period we call it chatter.

lg
no neat sig line

 

[IanN]

Hi,

Regarding tangential cutting tools, there is loads of information out there in old text books.

The tangential tool form has been in common use for at least 200 years - see

https://taths.org.uk/tools-trades/articles/88-heel-tools-an-experiment-with-old-methods

Remember that tool forms used over 100 years ago were often optimised for use on machines powered by foot treadle - ie low power and low rigidity

Second point - register for a course in machine work at your local college, or join your local model engineering club. You will learn more in an hour with an experienced machinist looking over your shoulder than in a whole year of "trial and error"

I'm a bit bias in my opinions - I teach engineering apprentices for a living, so I would always recommend live interaction with experienced people over a video.

Finally, remember that (in the UK) the apprenticeship to become a qualified machinist takes five years of full time practical experience in industry and theoretical study at college - a total of about 10,000 hours. If you devote 5 hours a week to your hobby, then in 40 years, you will have the same experience as a newly qualified apprentice.....

All the best,
Ian

Hi,

Meant to include a pic of the “traditional” form of tangential tool

The two tools in the middle are the tools to look at. The tool at the bottom is for a shaper and has the cutting edge arranged so it is level with the bottom of the tool shank - this will give you problems if you try to use it as a lathe tool

All the best,
Ian

 

[goldstar31]

Actually, I've used ALL these types of tools both in a small lathe and a hand shaper but several things emerge.

Almost certainly they will have been made from carbon steel and in the hands of a 'newbie' will be difficult to sharpen. I recall them in A.H Smith's Advanced Machine Tool book- which is available on the 'net for free. It's great book- a bit dated but it has stuff in it that doesn't often appear now. It's got some great maths stuff on tool grinding!

Again on supporting materials for machining, I certainly agree with Cogsy about tail stock support but I would add the desirability of having things things like fixed and running steadies-- even if they are made out of wood.

Thinking of holding things, we seem to have lost the catspaw chucks and 'Keats Plates'

Now that my summer holidays in France are over I have to get back to the very humdrum but essential bit old cast iron -well Meehanite plate that I can pepper with tapped holes and drilled holes despite having lots of so called proper vises etc.

Norm