Parting off

[Peter Simpson 3Participant @petersimpson3]

Hi all,

I have just been asked to make a part

Final dimensions are as follows

BMS 34mm diameter 2.8mm thick with a M10 x 1.0 hole through the centre Basically a large washer. I tried drilling and tapping the central hole, then attempted to parts off over length. Using various parting off tools I could not part off “slices” as the parting off tool just kept grabbing half way through the cut. Any ideas how to proceed ?

[Andrew CrowParticipant @andrewcrow91475]

Hi Peter, I think a bit more information would be needed ie machine being used, type of parting tool, front or rear tool post, spindle speed, coolant/lubricant being used etc

Andy

[HollowpointParticipant @hollowpoint]

My guess is that your parting tool isn’t dead square to the face of the chuck. If you go in at an angle it will almost certainly grab.

[JAParticipant @ja]

There are a lot of things that can go wrong parting off. Try or correct:

1. Is the tool the correct height?
2. Try a rear tool post.
3. Always cut or move the tool away from the work.
4. Remove swarf frequently
5. Use slow speed.
6. I consider 12mm, radial, a deep parting off cut. Do the first 4mm, remove the tool and move half a tool width away from finishing face. Then cut the next 4mm. Return the tool to its first position and do the next 4mm. And so on.

JA

[Roderick JenkinsParticipant @roderickjenkins93242]

I suggest you use a parting blade with a carbide insert.  The insert is wider than the blade and gives clearance to the supporting blade.  Another suggestion is to be bold with both spindle speed and feed rate.

Rod

[JasonBModerator @jasonb]

I take it you did not buy the bandsaw you were asking about previously. If you did lop it off with that and then face to width.

As per first reply without knowing the lathe and setup it is hard to offer advice.

You also mention “sliceS” do you have a lot of material sticking out the chuck to make multiple parts?

[Grindstone CowboyParticipant @grindstonecowboy]

The usual, and very good, advice is to have the tool on exact centre height. However, I’ve found – possibly due to a bit of flex in my setup due to wear – having it a fraction higher than centre helps. Not a lot, of course, maybe up to 5 thou.

Rob

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