Need help with grinding down a M4 tap shank

[phomann]

Hi,

I need to grind down the shank diameter of some M4 taps to 3.5mm The shanks are currently about 4.5mm dia.

I need to do this so that the tap will fit into a Tapmatic NC/R00 tapping head.

The max recommended tap size is M3, but as I'm going to be tapping aluminium sheet 2-3mm thick, I don't see this as an issue.

Is anyone able to do the grinding for me? I'm guessing it will need to be done on a lathe with a toolpost grinder.

I have 4-5 taps to be done.

If anyone can help me out, please PM me.

Cheers,

Peter.

[neilw20]

Peter,

Have you thought of center-less grinding?
It is easier than you think, once you set it up.

Neil

Here are some ideas.
I have done really crude hand done ones.


centerless grinding - Google Search

[awemawson]

Hi,

I need to grind down the shank diameter of some M4 taps to 3.5mm The shanks are currently about 4.5mm dia.

I need to do this so that the tap will fit into a Tapmatic NC/R00 tapping head.

The max recommended tap size is M3, but as I'm going to be tapping aluminium sheet 2-3mm thick, I don't see this as an issue.

Is anyone able to do the grinding for me? I'm guessing it will need to be done on a lathe with a toolpost grinder.

I have 4-5 taps to be done.

If anyone can help me out, please PM me.

Cheers,

Peter.

I'd expect to do it between centres on a cylindrical grinder. The working end of small taps usually have a male centre - ie a point, and there will be a female centre at the gripping end. I'd offer to do it but we are literallly poles apart!

AWEM

[phomann]

Peter,

Have you thought of center-less grinding?
It is easier than you think, once you set it up.

Neil

Here are some ideas.
I have done really crude hand done ones.


centerless grinding - Google Search

Hi Neil,

Thanks for the suggestion. I don't want to do this myself though. No time, or is it lazyness. One or the other.

Cheers,

Peter.

[phomann]

I'd expect to do it between centres on a cylindrical grinder. The working end of small taps usually have a male centre - ie a point, and there will be a female centre at the gripping end. I'd offer to do it but we are literallly poles apart!

AWEM

Hi Andrew,

Thanks for the reply. That's a shame, since they came from the UK. I bought them as they were reduced shank taps. Didn't realise that they then increase in diameter where they fit into the tap holder.

It makes sense though. It's easier to grip the larger diameter.

Some of the ones I ordered were these;
Engineering Supplies - M 4x0.7 Metric Spiral Point Reduced Shank Tap DIN 376 Titanium Nitrided for longer life

But they don't look like them. The shank also has a point unlike the picture. Also the picture shows the shank reduced all the way.


Cheers,

Peter.