Stuart M.T.B. 1a

[BasKoParticipant @basko]

Hello,

I own an old Stuart M.T.B. 1a engine and looking for the drawings. Can anybody help me out where I could get those?

Many thanks!

[BasKoParticipant @basko]

[Brian HParticipant @brianh50089]

I thought that Stuarts would be the obvous place to look but the MTB engine is not on their site.

Hopefully someone has one tucked away that you can get a copy from.

Brian

[Former MemberParticipant @formermember12892]

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[JAParticipant @ja]

I am intriged about the engine. I assume it is a model of a Victorian motor torpedo boat engine. It would be nice to see a couple of pictures of it and some idea of its size, please.

JA

[JasonBModerator @jasonb]

Fair bit about the MTB range here, look at the top under "marine" for individual engines.

Looks like it could be carved from solid so I'd be interested in a drawing if one turns up.

[Former MemberParticipant @formermember12892]

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[Former MemberParticipant @formermember12892]

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[Brian HParticipant @brianh50089]

I wouln't mind one of those from Stuarts at £1 10 shillings!

Brian

[JAParticipant @ja]

To all

Many thanks. My curiosity has been satisified.

I only knew of Stuart's website which is good and very useful. The one that Jason and Bill gave is splendid and will be view at leisure soon.

As for the engine, it is not what I am looking for but if a set of castings became available I could be interested (even without drawings).

JA

[BasKoParticipant @basko]

Hello,

this is my engine. The model is complete even if the photo doesn’t shows the fully assembled engine.

Sadly 3-4 threads are stripped. I have to find a solution for this. What would you do? Replace the the existing threats by M3 threats?

Edited By BasKo on 19/07/2021 11:16:27

Edited By BasKo on 19/07/2021 11:16:39

[Brian HParticipant @brianh50089]

That would depend on what size the stripped threads are and how close to any edges they are. If you have any pictures to show how close to the edges they are that would help.

As to size, they could be BA sizes but more probably Whitworth or BSF. Whit threads go down at least to 1/16" but taps may be difficult to find unless second hand.

If you could indicate where you are in general terms i.e. Not your full address, then someone on here may be able to identiy what sized threads and therefore suggest a repair method.

Brian

[Former MemberParticipant @formermember12892]

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[Brian HParticipant @brianh50089]

It looks to me that the threads could be opened up to the next suitable size and fittted with threaded bushes tapped to a convenient size or, fitted with stepped studs where one end is to the size of the opened up holes and the other end is the original size,

It would be interesting to read what others think.

Brian

[Former MemberParticipant @formermember12892]

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[Michael GilliganParticipant @michaelgilligan61133]

Posted by Brian H on 19/07/2021 15:15:49:

[…]

It would be interesting to read what others think.

Brian

.

Just guessing, from the photo … I would think there is plenty of room for Helicoils

MichaelG.

[BasKoParticipant @basko]

Here are some photos with some marks of the threads which are stripped.

There is enough room for a new thread, but the diameter of screw head will be the limitation.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by BasKo on 19/07/2021 15:47:47:

.

There is enough room for a new thread, but the diameter of screw head will be the limitation.

 

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… which would, I think, make HeliCoil inserts the logical choice.

MichaelG.

.

For the avoidance of doubt: I have no commercial interest in the product !

https://helicoil.in/pdf/HeliCoil%20Catalogue.pdf

Edited By Michael Gilligan on 19/07/2021 16:04:27

[JasonBModerator @jasonb]

If the cheese head screws are original then custom made ones with the same size head and an enlarged thread would be an option, you could stay with Whitworth threads that way.

[BasKoParticipant @basko]

Thanks for all the response!

@JasonB: yes, the cheese head screws are original! Thus nuts and bolts would destroy the original look.

I think helicoil or to enlarge the thread is the way to go.

Does anyone know which thread size has been used? br indicated BSW? I would assume 3/32 BSW then.

 

Edited By BasKo on 19/07/2021 17:01:51

Edited By BasKo on 19/07/2021 17:05:14

[JasonBModerator @jasonb]

Early Stuart engines use Whitworth so I should think that would apply to this engine too. What diameter are the screws?

I'd take a stab at them being 3/32" whit so if making new screws then 1/8" whit

[Michael GilliganParticipant @michaelgilligan61133]

3/32” BSW is 48tpi … which might explain why they stripped

MichaelG.

[Former MemberParticipant @formermember12892]

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[JasonBModerator @jasonb]

Posted by Michael Gilligan on 19/07/2021 17:10:04:

3/32” BSW is 48tpi … which might explain why they stripped

MichaelG.

And why 1/8" whit at 40tpi may be better than the originally suggested M3 x 0.5 which is almost 51tpi.

Helicoils would be same pitch as the original screw so still quite fine.

[BasKoParticipant @basko]

@JasonB: die screw diameter is 2.3xmm. Thus I think BSW 3/32 is the correct size. This was also the reason why I thought about rethreating as M3 because the holes needs to be drilled by 2.5mm. But then the engine would have metric and inch screws…

I also checked helicoil, but it looks like that this system isn’t available for 3/32“ threats.

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