Stuart 10V Exhaust Thread

[FerrumParticipant @ferrum]

I am building a 10V and am currently considering tapping the cylinder for the exhaust.

The Stuart plans specify a 1/4 x 32 thread. Would it make more sense to use 1/4 x 40?

I apologise if this is a daft question!

[FerrumParticipant @ferrum]

[John RuddParticipant @johnrudd16576]

IIRC, the 32tpi thread slightly deeper in its thread form….

The Purists on here would probably say ….'Follow the plans, that is what they are there for'…and no doubt I'll receive flack over this statement, but as no one else has come to your aid….no reason not use what you want to use…..You could even use a Metric equivalent if you wanted…..

[Neil WyattModerator @neilwyatt]

40 tpi is quite a fine thread for cast iron, but you hsould be OK with teh fine grain stuff Stuart use.

I went the other way and used 0BA on mine

Neil

[FerrumParticipant @ferrum]

Thank you very much for your replies, John and Neil.

I had not considered the thread depth, I have to confess. I was more prosaically considering the relative prices of the unions. I have much to learn!

Ron

[John Stevenson 1Participant @johnstevenson1]

Posted by Neil Wyatt on 10/04/2015 17:04:07:

40 tpi is quite a fine thread for cast iron, but you hsould be OK with teh fine grain stuff Stuart use.

I went the other way and used 0BA on mine

Neil

.

You mean wonky M6 Neil ?

[JasonBModerator @jasonb]

I'd use the 40 tpi for all the 1/4" ME threads on the Stuart range then you engine will be compatible with all the commercial steam fittings not just stuarts unusual choice. Would not worry about thread depth into the iron I've used 40tpi in the stuff plenty of times and at larger diameters.

Also saves buying 1/4×32 taps and die that you won't get a lot more use from.

 

J

Edited By JasonB on 10/04/2015 17:56:46

[FerrumParticipant @ferrum]

Thank you for the advice, Jason. Money saved on taps and dies is not to be despised.

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

I used the thread M7x0.75 for inlet/exhaust in Stuart D10 since i has not all imperial treads.

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