Vickers Bl 8 inch Howitzer cannon of 1917

[Alan JacksonParticipant @alanjackson47790]

Magnificent work Mal. It will be great to see this when it can be exhibited.

Alan

[mechman48Participant @mechman48]

Superb as usual Mal; itching to see how you work the breech block.

George.

[Richard MillingtonParticipant @richardmillington63972]

Lovely build, a credit to you.

I am thinking of doing a Pak40, just trying to get some drawings/dimensions together, but seeing this I will have to up my game

[Neil WyattModerator @neilwyatt]

This really is shaping up to be a superb model.

[mal webberParticipant @malwebber91786]

Hello all

Thanks for the comments and interest in the Howitzer build ,Richard the pak40 would make a very nice model what sort of scale are you thinking of building it in .

Well small update on the Howitzer build not really got much more done than the last post not down to shed time but everything I have made lately I've managed to mess up on by silly mistakes and the part ends up in the scrap bin, what I did manage to make is the carriage bearing and bolt so it fastens from the underside and started on some of the tin work to cover the carriage, couple of pictures below of my very slow progress .

Thanks Mal

[Jeff DaymanParticipant @jeffdayman43397]

Looking great Mal! fully boxed frames – long before the hot rodders got onto the idea…..Cheers

[Robert ButlerParticipant @robertbutler92161]

I'm gasping for an update

Robert Butler

[Ady1Participant @ady1]

Hope he's ok

I found a booklet with 88mm details and I think the source site will have a lot of other historical military stuff for those people who are interested in militaria

Edited By Ady1 on 04/05/2022 00:13:11

[David George 1Participant @davidgeorge1]

Hi Mal hope all is well. I wondered if you would be taking your Howitzer to the show at Midlands exhibition center this year. Many people would love to see it.

David

[mal webberParticipant @malwebber91786]

Hello everyone, I have been working on moving the shed about and making it bigger ,haven't done any progress on the Howitzer since the last post but will start up again as soon as thing's are sorted. David may be next year when the build is a bit more together.

Thanks Mal.

[mal webberParticipant @malwebber91786]

Edited By mal webber on 12/05/2022 22:27:44

[mal webberParticipant @malwebber91786]

Hi all ,well no room for the Howitzer in the shed at the moment so thought I would have a go at the breach threads which went all wrong towards the end, not realising that the dividing head had slipped and managed to brake of the tip of the cutting tool with out realising that it had so this being a total fail but second attempt will be started soon, thought I would put up some pics as not posted in a while even if its a fail

Edited By mal webber on 12/05/2022 22:44:50

[mal webberParticipant @malwebber91786]

Forgot to mention this was not in scale with the Howitzer in size or the number of threads just a practice run at trying to figure it out , lots of lessons learned by trying so will see how the second attempt will go.

Thanks Mal.

[Dominic BramleyParticipant @dominicbramley60728]

Seeing this thread up and running again has made my day.

Glad you're well Mal!

Dom

[Peter Bowers 3Participant @peterbowers3]

Hi Mal watching this with interest from Australia. My Grand father was is the Siege Artillery in WW1. Im hoping to build one of these soon, not as big as yours though

[Mick B1Participant @mickb1]

If you decide you wanna go for a Firearm Cert and shoot it, I've still got some Cordite MDT 5-2 taken from 303 Mk.VII ball, that should work fine if you chop it coarsely…

[SillyOldDufferModerator @sillyoldduffer]

Posted by mal webber on 12/05/2022 23:01:00:

Forgot to mention this was not in scale with the Howitzer in size or the number of threads just a practice run at trying to figure it out , lots of lessons learned by trying so will see how the second attempt will go.

Thanks Mal.

Nonetheless impressive! How did you go about it? There are two stepped threads and a blank sector:

My guess.

1. Bore the breech to suit the inner thread diameter and cut the thread conventionally.
2. Broach the second and third sectors,
3. Cut the second thread group laboriously, one at a time, over 60°.

Doable, but tedious skilled work; I'd get bored and mess-up. Is there an easier way, or am I left slack-jawed in amazement again? Plenty of good work shown on the forum, but your Howitzer is ticking all my boxes!

Dave

[Ady1Participant @ady1]

I have often wondered what the machining solution for these things was but have never seen anything

…The obvious solution was to make a sliding breech block…

[Richard MillingtonParticipant @richardmillington63972]

Posted by mal webber on 30/11/2020 19:44:41:

Hello all

Thanks for the comments and interest in the Howitzer build ,Richard the pak40 would make a very nice model what sort of scale are you thinking of building it in .

Apologies I missed this.

Pak 40, not to scale or even 100% accurate. All made from stainless from the scrap tub apart from the nylatron tyres!

17" total length from tip of the muzzle brake to the towing hitch.

[mal webberParticipant @malwebber91786]

Hello all.

Richard that is a fantastic looking model of the PAK 40 very impressive and detailed nicely, good size as well at 17" thanks for sharing.

Peter couple of pictures on here when you start the build would be very interesting.

Mick thanks for the offer but will keep it as a model.

Dave that is pretty much how I went about it, although the cut outs in the breech would never work with a swing-away plug. So I have been trolling the internet for a good few days now and am about to start my second attempt, Ady1 it sure would make it easier to have a sliding plug.

Thanks, Mal.

[BufferParticipant @buffer]

Mal

How do you cut the threads though?

Thanks

[Mick B1Participant @mickb1]

Posted by mal webber on 18/05/2022 18:21:53:

…

Dave that is pretty much how I went about it, although the cut outs in the breech would never work with a swing-away plug. So I have been trolling the internet for a good few days now and am about to start my second attempt, Ady1 it sure would make it easier to have a sliding plug.

Thanks, Mal.

I think you're right that there's an issue with a hinged breechblock carrier and the arc of insertion of the block creating interferences. I'm sure I've seen drawings somewhere of the the reliefs that were used to prevent them.

There an amazing and impressive animation of the breech workings of the 15" naval gun here:-

**LINK**

… but it skates over the problem and I wonder if it cheats…

[Mick B1Participant @mickb1]

You can see the relief arcs for the swinging breechblock on P7 of this document:-

**LINK**

[SillyOldDufferModerator @sillyoldduffer]

Posted by Mick B1 on 18/05/2022 20:11:08:

Posted by mal webber on 18/05/2022 18:21:53:

…

Dave that is pretty much how I went about it, although the cut outs in the breech would never work with a swing-away plug. …

 

I think you're right that there's an issue with a hinged breechblock carrier and the arc of insertion of the block creating interferences. I'm sure I've seen drawings somewhere of the the reliefs that were used to prevent them.

There an amazing and impressive animation of the breech workings of the 15" naval gun here:-

**LINK**

… but it skates over the problem and I wonder if it cheats…

The problem would be solved if the breech mechanism moved back slightly before and whilst swinging out.

The animation is amazing, but I can't see any sign of it – though the horizontal movement might be too small. Two possibilities: the turning arm on the right cams as it rotates, and the carrier pintle unscrews as well:

 

Not convinced by my own suggestion, though the comment 'Axial Vent Bolt is keyed to Carrier Pintle so doesn't rotate with Breech Screw' may be supportive.

By the by can't see the relief angles in Mick's other interesting document: page 7? Sorry if I'm seeing and not seeing again.

Dave

 

Edited By SillyOldDuffer on 19/05/2022 09:31:46

[Mick B1Participant @mickb1]

Posted by SillyOldDuffer on 19/05/2022 09:31:04:

…

By the by can't see the relief angles in Mick's other interesting document: page 7? Sorry if I'm seeing and not seeing again.

Dave

 

Edited By SillyOldDuffer on 19/05/2022 09:31:46

It only shows as 7 of 61 on the pdf page count at the top of the view – on the document image itself it's in the drawings facing page 10 as printed. There are arcs cut away to allow the swing-passage of the breech block. This will obviously have reduced the pressure limits for the closure, but equally obviously this will have to have been calculated for – though I've little idea offhand how to approach that…

Here's a screengrab:-

Looks as if there might be a corresponding bite out of the block itself too.

Edited By Mick B1 on 19/05/2022 16:27:47

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