Parting off

[Alfie PeacockParticipant @alfiepeacock58331]

I am about to do some parting off using my QCTP, it has a 1/2 parting off tool holder.The problem I have is that I have several 3/8 th bits and they are to small for the holder. I have found a old 1/2 x 1/8th file can this be used if I grind the teeth off, I know that I must keep it cool as not to over heat when grinding. I will be parting off 3/4 steel.

Edited By Alfie Peacock on 05/10/2017 14:57:18

[Alfie PeacockParticipant @alfiepeacock58331]

[Chris Evans 6Participant @chrisevans6]

Sounds like a recipe for a load of grief. Proper parting blades are cheap enough, you do need to have your lathe gibs on the tight side when parting to avoid snatching.

[VicParticipant @vic]

The Chipbreaker blades on this page are brilliant.

**LINK**

[egaParticipant @ega]

A parting tool made from a file should probably be suitably heat treated since a dig in might well otherwise cause it to fracture.

[Jon CameronParticipant @joncameron26580]

I've got a parting off tool made from HSS steel, its a lot of work grinding down to 3mm. If you do make sure that one side of the steel is perfectly straight, and the other slightly tapered in from the edge of the tool, this will eliminate chatter.

[Alfie PeacockParticipant @alfiepeacock58331]

Thanks for the replies, as I needed to use the ground file at the time it worked fine. I was making a cylinder that needed cooling slots so took a chance.but have a tool on order. Its interesting how did the amateur part off back before HSS was ready available.

[Brian OldfordParticipant @brianoldford70365]

Having obtained one a few years ago I cannot recommend too strongly to get a rear toolpost fitted with a proper parting tool blade.

[Peter G. ShawParticipant @peterg-shaw75338]

I have a parting off tool using a 1/2 in x 1/8 in file mounted in a homemade holder similar to the one in Len Mason's book "Using the Small Lathe", although Mason suggested using a worn out hacksaw blade.

Mine is 1.84mm wide at the tip, full 1/2in depth, and through experimenting it has a blade length of about 10mm. I have to use a lot of cutting fluid, ie once the cut starts, keep the cut full, and deliberately force it into the work. Under these conditions it works well, but if the fluid runs out, or the cut slackens off, then chatter can occur. I have not heat treated the file – just used it as it came. I have left the top surface horizontal and used the original safe edge for this purpose. No dig-ins at all.

In respect of pre-HSS days, it is worth remembering that, according to Tubal Cain/T D Walshaw, a properly hardened and tempered carbon steel tool is actually harder than HSS. Also, turning speeds using carbon steel are a lot slower than HSS because of the heat problem. HSS = High Speed Steel.

Regards,

Peter G. Shaw

p.s. I note that you have done the job successfully using the ground down file. Congratulations.

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