Best approach to pip removal

This topic has 9 replies, 9 voices, and was last updated 11 October 2026 at 16:34 by Colin Teasdale.

Viewing 10 posts - 1 through 10 (of 10 total)

Author

Posts
10 October 2026 at 23:13 #868870
Bill Phinn
Participant
@billphinn90025
When you have to remove a small pip after parting off a small (i.e. less than 1/2”) diameter part, and the pip you’re concerned with is on the back of the piece you’ve parted off, meaning the part has to be re-chucked and there is a slight increase in runout as a consequence, what is the best approach?

I ask because the forces involved in removing the pip seem very considerable at times, whether I face off the pip or advance the carriage to do so, or use a combination of both.

What type of tool is best for the job and what sort of spindle rpm? I’m doing brass mainly (e.g. knurled thumb screws), am after a very good surface finish (maybe even a slightly domed end) and I’m wondering whether this might be a job for a hand-held tool, not just to achieve the dome but to remove the pip as well.
Advert

11 October 2026 at 01:18 #868883
peak4
Participant
@peak4
I can’t really speak for brass pips, but generally I’ve found that the job is very sensitive to tool height.
Also, particularly if the pip is off centre, ground carbide inserts are more sensitive to chipping, as it’s a small area of metal that’s hitting the insert at a comparatively low speed.
I tend to knock off the pip as fast an RPM as possible, and face at whatever speed seems appropriate.
Easier with a VFD driven motor of course.
Alternatively, use a fine file, and then face.

Bill
11 October 2026 at 02:47 #868887
Michael Gilligan
Participant
@michaelgilligan61133
It seems like an ideal job for the hand Graver

Sorry … old age and Arthritis have made me too clumsy to demonstrate.

MichaelG.

.

Edit: … You might start here:

.

.
11 October 2026 at 06:48 #868888
JasonB
Moderator
@jasonb
If you want a domed end then you have two options.

1. File against the rotating work, moving the file to create the dome shape and you can just file off the pip first. Single cut lathe file will make quick work of it.

2. Requires a better grip so maybe a threaded split bush so that you can use a form tool set on ctr height it will also deal with the pip

For a flat end if filing off the pip is not good enough then just a sharp HSS or **GT insert with small 0.2 tip radius. Ideally hold in a split bush as you won’t get a solid grip on a threaded surface so the pip may want to ride up over the tool.

In all cases small dia brass wants a fast speed probably as fast as your lathe will go but whatever is quick to select.

The pip can be reduced if you use a parting tool with an angled end. Again what ever parting tool used needs to be sharp.

Or do it a sI do when making screws for my engines. Turn shank and thread (knurl in your case). Saw off from bar a bit over length. Hold by threaded end as appropriate and use a form tool to shape the head. Works well with batches of screws as well as singles
11 October 2026 at 08:17 #868889
Dell
Participant
@dell
If I want a slight dome on a part no matter if it’s on the Pultra or the Myford I use a graver because it will also remove the pip but if the item is to be slotted then I don’t mind the pip as it shows centre of part, my hand parting tools have slight taper left & right so if I want the pip on part I use right taper or left if I don’t want pip on part.

This video may help as the end of it has a rounded end it was for a drum clock I restored.
11 October 2026 at 08:38 #868891
Hollowpoint
Participant
@hollowpoint
You can get such a thing as an engineering chisel, for exactly this type of thing. Cut the pip off flush with the chisel and then face the part as normal. CCGT tips and high speed give a fantastic finish.
11 October 2026 at 10:44 #868903
Michael Gilligan
Participant
@michaelgilligan61133
Nice demo, Dell

… compared with all that, of course, removing a pip is a doddle !

MichaelG.
11 October 2026 at 11:03 #868904
Julie Ann
Participant
@julieann
Use a right hand parting tool so it doesn’t leave a pip on the work in the first place.

Julie
11 October 2026 at 16:18 #868933
Howard Lewis
Participant
@howardlewis46836
Grinding a HSS parting tool with a slight front angle may help, but it does impose a sideways force on the tool, (So you might get a sloping end face) and makes the swarf wider than the groove, so the risk of a jam up increases.

Using a carbide tipped parting tool, with its central groove, giving two narrow streams of swarf towards the centre of the groove may help.

Howard
11 October 2026 at 16:34 #868937
Colin Teasdale
Participant
@colinteasdale
I find that I only get a pip if the tool height is wrong.

A pip shows the tool is too low, while a slight ‘mound’ shows the tool is too high. Adjust the tool so that you can face the pip off and the tool should be at the correct height for the next operation.
Author

Posts