I recently decided to replace my "home brew" (and often failing) thru-head adapter. After some catalog "shopping" I settled on the HoldFast.
When I got the HoldFast, I decided that it wasn't quite right either, I wanted a nut and washer on the out-board side, to hold the assembly tight (I didn't want to cut the tube to length).
A quick look at the tube suggested that it was threaded at 3/8-fine. Since I didn't have an 3/8-24 nuts, next trip to town..
Well, when I tired to put the nut on, I quickly figured out it's not threaded at 24.
Maybe it's a 10mm... a quick check with my only 10mm nuts showed its not 1.5mm. Maybe 1.0mm.
Only this time I got out my tap&die set and used the thread gauges...
Turns out the shaft is not 1.0mm, nor 1.5 mm, nor 24 tpi, not 28 tpi, but rather 27 tpi (ie NTP thread).
So... I grabbed a 3/8-24 nut and re-threaded it at 27.
I have a tight fit with the HoldFast adapter and can draw up to about 25 inches of vacuum
TTFN
Ralph
When I got the HoldFast, I decided that it wasn't quite right either, I wanted a nut and washer on the out-board side, to hold the assembly tight (I didn't want to cut the tube to length).
A quick look at the tube suggested that it was threaded at 3/8-fine. Since I didn't have an 3/8-24 nuts, next trip to town..
Well, when I tired to put the nut on, I quickly figured out it's not threaded at 24.
Maybe it's a 10mm... a quick check with my only 10mm nuts showed its not 1.5mm. Maybe 1.0mm.
Only this time I got out my tap&die set and used the thread gauges...
Turns out the shaft is not 1.0mm, nor 1.5 mm, nor 24 tpi, not 28 tpi, but rather 27 tpi (ie NTP thread).
So... I grabbed a 3/8-24 nut and re-threaded it at 27.
I have a tight fit with the HoldFast adapter and can draw up to about 25 inches of vacuum
TTFN
Ralph