Cheddar steam fitting thread size

[btrippis]

I have a couple Cheddar blilers and have not been able to figure out
what the thread size is on the steam line, I have some 1/4 40
nut and nipples that fit my John Hemmens steam engine but the
thread sise on the Cheddar boiler is not 1/4 40. A little help
would be greatly appreciated.
Regards, Brian

[crash93]

You need 1/4 x 32 union nuts and 5/32 union rings to fit on 5/32 OD pipe

so it will be 1/4 x 32 for fittings in boiler water gauge etc exept the pressure gauge on the left of the steam turret looking from the burner and I cannot remember the size of that

Peter

[btrippis]

Peter, Thanks for the quick reply. Great help I need to get busy and order some copper tube.  I have some 1/8 inch.  Looks like I need 5/32 and
some union nuts to go with it.
Regards, Brian

[crash93]

These are the sizes I got from Jerry of Clevedon Steam <clevedon> I've Have checked and they do fit . he is handy for Cheddar info being ex cheddar and small parts O rings nuts olives etc

Peter

[btrippis]

After searching several model steam web-sites here in th US all I could
find were 1/4 40 Union nuts. So I  ordered some from Stewart Models on their on line store. A little pricey but at least they have them. Looks like 1/4 40 is common on this side of the pond.
Regards, Brian

[derekwarner_decoy]

Hi PD's ...& yes 1/4 X 40 TPI unions/fitings/valves.... appear universally & appear to be universal.... but they are not  :rant

The attachment shows two 1/8" OD tube fittings with solder cones & 1/4" X 40 TPI nuts...both from British manufacturers,..... but even an  :hmph OZZIE can spot the difference

The fitting on the top has a shorter length 1/4" X 40 TPI thread & nut & consequently, you cannot use one of the newer nuts & solder cones on the older [longer length] union or valve... the nut bottoms out prior to the solder cone becoming captive  :twisted:

Naturally a simple fix is to carefully shorten the effective thread length on the valve body or union 1/4" X 40 TPI male thread as thankfully  :respect2 both manufacturers have used the same solder cone geometry ......included angle & principal dimensions etc