Adjustable tap? Anyone seen one of these before?

[RWD3M]

I have adjustable reamers but haven't seen an Adjustable tap before. This is M18 (spark plug thread) and popped up on another forum then sent to me by a pal.

Any suggestions on its prupose/application?

 

[northwest]

Well that is a new one and I think I have seen it all!

 

[bricol]

I guess it allows you to get a looser/tighter fit.

You can get taps specifically ground for fits - allows a thread to "float" while using a location diameter to align components screwed together.

 

[Dapph2]

I think of it as a BSP Type taper fit designed for gas or hydraulic applications when using banjo connectors . Google says slightly different .

 

[Porkypine]

A new one on me too ! ^ the idea of a BSP taper malarkey makes sense certainly, I've done lots of pipe fitting though and I've not seen anything like it.
Interesting item...

 

[Erie Fred]

Interesting, never seen one like that before.

I have a few Geometric die heads and a couple of geometric taps.
These taps are above 1" dia. and use similar chasers as the die heads, they don't collapse
but IIRC are adjustable.

 

[Seadog]

Perhaps it collapses sufficiently to be onserted into a thread with a damaged lead? It can then be expanded into correct alignment to reform the thread.

 

[Seadog]

And lo...

https://www.amazon.co.uk/Powerbuilt-Straightening-Motorcycle-Repairs-Collapsible/dp/B0014FGVVW/ref=asc_df_B0014FGVVW?mcid=95e653c5ff553cb5b86427e9bce6c019&th=1&psc=1&hvocijid=17856115733513464198-B0014FGVVW-&hvexpln=74&tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=17856115733513464198&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9044959&hvtargid=pla-2281435176858&psc=1&gad_source=1

 

[Erie Fred]

And lo...

https://www.amazon.co.uk/Powerbuilt-Straightening-Motorcycle-Repairs-Collapsible/dp/B0014FGVVW/ref=asc_df_B0014FGVVW?mcid=95e653c5ff553cb5b86427e9bce6c019&th=1&psc=1&hvocijid=17856115733513464198-B0014FGVVW-&hvexpln=74&tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=17856115733513464198&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9044959&hvtargid=pla-2281435176858&psc=1&gad_source=1

I see that ^ (never seen before) however it doesn't appear to be built the same as the OP's.

 

[Seadog]

There are many ways to skin a cat...
But I do understand what you're saying.

 

[RWD3M]

And lo...

https://www.amazon.co.uk/Powerbuilt-Straightening-Motorcycle-Repairs-Collapsible/dp/B0014FGVVW/ref=asc_df_B0014FGVVW?mcid=95e653c5ff553cb5b86427e9bce6c019&th=1&psc=1&hvocijid=17856115733513464198-B0014FGVVW-&hvexpln=74&tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=17856115733513464198&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9044959&hvtargid=pla-2281435176858&psc=1&gad_source=1

Well would you look at that!

Nice find Graham! Thanks.

 

[Agroshield]

Is the tap M18 coarse or M18 fine? I think spark plugs and injectors use the finer pitch thread.

M18 is not a common thread so that would narrow down the possiblities.

Another possibility is for use if the item is to be (electro-) plated. Then the pre-plated thread needs to be oversize so it is correct after plating.

 

[RaceDiagnostics]

I have one like this, it goes right into the spark plug hole before being expanded into the thread and then extracted outwards bring any debris with it.

 

[Erie Fred]

There are many ways to skin a cat...
But I do understand what you're saying.

The OP's tap is just adjustable, not whilst down in the bore.

 

[mr haynes]

1st cut, 2nd cut?

 

[E T]

I have adjustable reamers but haven't seen an Adjustable tap before. This is M18 (spark plug thread) and popped up on another forum then sent to me by a pal.

View attachment 517459
Any suggestions on its prupose/application?

Any names/numbers on the shank?

 

[E T]

Another possibility is for use if the item is to be (electro-) plated. Then the pre-plated thread needs to be oversize so it is correct after plating.

That's a good one, but they usually use oversize taps for that. I think an oversize tap is easier/cheaper to produce than an adjustable one plus you can't use this one in a blind hole.

 

[E T]

The OP's tap is just adjustable, not whilst down in the bore.

And it has straight flutes so the chips are going to go straight down into the combustion chamber if used on a mounted cilinder head.

 

[premmington]

I have one like this, it goes right into the spark plug hole before being expanded into the thread and then extracted outwards bring any debris with it.

View attachment 517476

I got these - if top thread is ruined you can start at good threads at the bottom and work your way "up"

They work - they a good thing...

 

[RWD3M]

Any names/numbers on the shank?

I have no idea, that's the only picture I have.