M16 x 20 and 5/8 x18 unf??

[Blobber]

So if I have a part with an M16x20 female thread but the part with a male thread that needs to go into the M16 im struggling to identify, I think it may be 5/8x18 UNF, it screws in about 8 turns then stops, does that sound right?

 

[Kram]

Mixing metric sizes with TPI is not going to end well I think. 20tpi is very close to 1.25mm pitch, and 18tpi is not far from 1.5mm pitch, so could be a metric fine thread.

What is it from? What is it?

 

[Blobber]

Basically the control cable outer seems to have the imperial thread, the new valve block has extension which are m16x20 so I was hoping to run an imperial tap down the new valve block extensions to take the old cables
this shows the old block with the 1 remaining cable attached to the extension
It seems very close as the cable will screw into the new extension about 8 turns

 

[Kram]

There is no M16x20 tpi, do you mean m16 x 2.0? Have you tried a set of pitch gauges?

Male threads typically measure 0.1-0.2mm under size as it makes them easier to die cut, so the 5/8" part could also be M16...

 

[Agroshield]

Mixing metric sizes with TPI is not going to end well I think. 20 tpi is very close to 1.25mm pitch, and 18 tpi is not far from 1.5mm pitch...

An alternative way to state the same thing is that 2.0mm pitch is 12.7 tpi so nowhere near the 18 tpi of 5/8" UNF.

Hence, if the fittings go together, some further investigation is required.

A set of pitch gauges is less than £6 (https://www.amazon.co.uk/Thread-Cutting-Metric-Imperial-Stainless/dp/B0D2TQFT3G).

Every household should have one.

 

[Blobber]

There is no M16x20 tpi, do you mean m16 x 2.0? Have you tried a set of pitch gauges?

Male threads typically measure 0.1-0.2mm under size as it makes them easier to die cut, so the 5/8" part could also be M16...

Yep think your right m16x2.0

 

[Blobber]

An alternative way to state the same thing is that 2.0mm pitch is 12.7 tpi so nowhere near the 18 tpi of 5/8" UNF.

Hence, if the fittings go together, some further investigation is required.

A set of pitch gauges is less than £6 (https://www.amazon.co.uk/Thread-Cutting-Metric-Imperial-Stainless/dp/B0D2TQFT3G).

Every household should have one.

I'm only working on the metric dimension from the valve block suppliers and an Internet search for the Bomford cables bringing up the imperial unf size, not sure what's what now

 

[carbonarc]

It seems the threads in the valve block are ISO metric fine. The thread pitch of a 16 mm diameter fixing of this specification is 1.5 mm, which equates to 16.93 tpi.

 

[Blobber]

It seems the threads in the valve block are ISO metric fine. The thread pitch of a 16 mm diameter fixing of this specification is 1.5 mm, which equates to 16.93 tpi.

So that would make the metric thread pretty close to the unf then which is why I'm getting a bit of engagement?

 

[carbonarc]

So that would make the metric thread pretty close to the unf then which is why I'm getting a bit of engagement?

I reckon so. Good luck with a quick repair.

 

[Agroshield]

What is the relative cost of a new valve block extension compared to a new cable?

Whichever is cheaper to replace is the correct part to modify.

M16 x 1.5 is the same as electrical glands so a die to use on the cable might be an alternative to an imperial tap into the valve block extension.

 

[Blobber]

What is the relative cost of a new valve block extension compared to a new cable?

Whichever is cheaper to replace is the correct part to modify.

M16 x 1.5 is the same as electrical glands so a die to use on the cable might be an alternative to an imperial tap into the valve block extension.

I can't get imperial extension for valve block, if I want to change the cables and remote handles to match the valve block it's about £300

 

[Fazerruss]

I can't get imperial extension for valve block, if I want to change the cables and remote handles to match the valve block it's about £300

Have you got a lathe and make an adaptor coupling?

 

[Blobber]

Have you got a lathe and make an adaptor coupling?

I have but will still need taps/dies to suit, I was hoping just to run an imperial tap down the extension piece to keep it simple

 

[ukracer]

I have but will still need taps/dies to suit, I was hoping just to run an imperial tap down the extension piece to keep it simple

Do you need them quickly?

 

[Blobber]

Do you need them quickly?

The guys are starting the stock fencing week Monday and I've about 500mtrs of grass/weeds/hedge to flail beforehand so yep you could say its getting tight!

 

[Kram]

First thing is count the number of threads per inch of the male thread. Easier, perhaps is to measure the distance for 5 or 10 peak-to-peak of the threads.

I guess a thread adaptor would mess with length and need a similar extension on the inner cable?

8 turns may be enough? Its a bowden cable, not sealing fluid? What happens if it lets go?

You can get a m16* 1.5mm pitch fine die cheap enough, run that down the cable end. However if it was originally a 5/8" thread it would be roughly 0.2mm smaller and have less thread engagement. On a 1.5mm pitch thread that shouldnt be too important.