Anyone able to help in Glos area?

[SVB]

Hi - a plea for help,

I have a 23mm dia shank Sorby turning tool that I’d like to turn the handle end of the shaft down to 19mm dia for a length of a couple of inches max.

My lathe only (only Chinese SEIG SC4) has a dia 20 spindle through hole and whilst I may be able to hold the cutting tip end across the gouge flute and use a steady down the bed to support the shank to be worked on, gut feel says turning HSS with carbide on a hobby lathe that far away from headstock ins’t going to work.

So, does anyone have a lathe that can do it for in exchange for a bottle of the local brewery’s finest?!?

THanks

Simon

 

[TFrench]

I think my lathe would have the power for it but I don't have flood coolant - I feel like this is the sort of job that would need it. If no-one else can do it I'd have a go but you get to pay for the inserts it burns up :lol:

 

[SVB]

Do you think it will be that tough? Where abouts are you?

 

[TFrench]

I had a quick search about turning hss and most people were saying it's pretty tough on tools. I guess ceramic inserts would work but I don't have any. Or a cylindrical grinder. I'm looking at getting a cutter grinder that has got a powered work head but if it happens it will be a while before it's in the shop and running. I'm located in South Leicestershire.

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[CHJ]

Simon, I would say that's a grinding job not a turning job, and not a cost less option even at that.

How long is your tool shank, if it's a short stub how about a good fit reduction sleeve.

If it's long, is it practical to bind the tool steel itself with firm cord to form a handle grip.

An image would help.

 

[SVB]

Chas,

Thanks for that - you’ve got me thinking.

Given it does not need to be super precise, I wonder if using my lathe and a steady I could get it running true enough at 100 rpm (or there abouts) to grind the required section (2” length max) with a power file with appropriate belt or even wide(ish) wheel on a grinder, both held by hand to work down that end of the shank?

Simon

 

[CHJ]

Simon, one thing you need to consider is that HSS tool steel is rather brittle ( see comments elsewhere on the forum about snapping smaller square stock)

If your need to use such a large diameter tool is because of the need to absorb shock or heavy loads then please consider the risk of the tool shearing at the reduced shank interface if there is any chance of a stress line being left behind (think glass cutting as a crude example)

 

[SVB]

Yes, I can easily avoid a sharp shoulder - good shout.

Out of interest, do turning tool manuf evenly harden the whole tool or is the shank / handle left softer than the flute I wonder?

Simon

 

[TFrench]

Test it with a file? Out of interest, why are you reducing it?

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[CHJ]

Out of interest, do turning tool manuf evenly harden the whole tool or is the shank / handle left softer than the flute I wonder?

By the very nature of HSS heat treatments (simplified think long soaks at hardening and annealing temps) I would expect the whole tool spindle/shaft to be treated to the same specification.

 

[SVB]

So, removed the tool from handle this evening only to find that inside the length of the brass ferrule the shank is already waisted down to 5/8” (and with a sharp shoulder only 1/8” into handle) so no turning required.

Phew!!

Thanks for all the helpful suggestions.

Simon.

 

[Trevanion]

I know you've already figured it out, but I wonder if standard carbide would cut hardened HSS at all, cutting a cutting tool sounds pretty hard going! :lol: Even with flood coolant and a fresh insert I still would imagine it would be not pleasant at all and you'd probably burn up cheaper inserts very quickly. Turning unhardened silver steel or stainless steel is pretty tough going compared to mild steel, Hardened HSS might not be doable in a hobbyist capacity.

I know someone that uses CBN inserts for turning hardened steel for certain components, but those inserts are like £50+ each.

Plus hardened steel comes off HOT!

[youtube]TnxR3HxoHcg[/youtube]

 

[SVB]

Wow, that’s dramatic!

This is what I had envisaged, simple carbide insert (and perhaps a dab of cutting oil).

Cutting HSS with Carbide insert

Simon