Taking of material on return stroke

[Cheesie]

On the return stroke I seem to be taking of more material than I thought it would most I've cut of in one pass would be around 0.4mm would moving up to 20mm from 16 stop this as maybe its flexing, or better carbide bts

 

[Scalarocco]

What you are describing is called a spring cut. Are you milling or turning? In very general terms it is normally a lack of rigidity in either the machine or the material being cut. As I say, this is a very general reason and all machines do it to a degree, but wear or poor setup are the prime causes. Depending on other factors that can also cause it, it would be beneficial to know exactly what it is that you are machining and with what machine.

 

[Cheesie]

Sorry for the cider only went into the garage to make sure everything was turned of

 

[Brad93]

Will be lack of rigidity or wear in your machine

 

[Cheesie]

Everything is tight on it no loose spots in any travel

 

[striker]

I sometimes get this if I use a course feed, then when I return it just knocks off the high spots. I think!. It is not such a problem since I've fitted my electric lead screw drive and I can set the feed really slow/ fine.

 

[Cheesie]

I sometimes get this if I use a course feed, then when I return it just knocks off the high spots. I think!. It is not such a problem since I've fitted my electric lead screw drive and I can set the feed really slow/ fine.

It's not a problem as such I'm more curious if there's a way out of it

 

[Hood]

I am not really following, your initial post, to me at least, seems to suggest you are taking a normal cut along the material but your pictures seems to suggest a facing cut.

You will always get some back cutting as everything will move as you reverse, how bad will depend on lots of things such as rigidity of machine and workpiece, type of tool, shape of insert, nose rad of insert, depth of cut etc etc.

 

[striker]

It's not a problem as such I'm more curious if there's a way out of it

Obviously if you take off some of the cut before going back, then wind in to where you were before adding more cut will solve this. I'm sure you're aware of that though!

 

[Gritineye]

What type of tooling are you using? I find that carbide or tipped tooling results in more of a spring cut than HSS, because it's less sharp.

HSS can be given a very keen edge that causes less flex on a lighter lathe.

 

[striker]

It may help to lock the saddle, if we are talking facing.

 

[Hood]

What type of tooling are you using? I find that carbide or tipped tooling results in more of a spring cut than HSS, because it's less sharp.

HSS can be given a very keen edge that causes less flex on a lighter lathe.

That may be because you are tickling with carbide, you need to take a good cut with carbide, almost always it is best to have a DOC of at least the nose rad.

 

[Brad93]

Everything is tight on it no loose spots in any travel

You won't feel the wear mate, you'd need a clock to measure it

 

[Cheesie]

What type of tooling are you using? I find that carbide or tipped tooling results in more of a spring cut than HSS, because it's less sharp.

HSS can be given a very keen edge that causes less flex on a lighter lathe.

Carbide

 

[striker]

Maybe worth trying hss. I use both but love my tangential tool holders with 1/4" m42 hss. I use them for most of my lathe work.

 

[Gritineye]

That may be because you are tickling with carbide, you need to take a good cut with carbide, almost always it is best to have a DOC of at least the nose rad.

Yep I am aware of all that carbide malarky, thanks anyway.