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Making a Gunning Punt and Punt Gun


Wildfowler
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Wildfowler,

I have only just found this topic - and that by accident.

I read the fowling articles without fail but rarely look under guns and equipment. Luckily it was passing through the new content section when I logged on.

I read the articles from start to finish and got a rollicking from the Memsahib for being late for dinner.

Absolutely superb build from start to finish.

One of the best topics I have ever read on PW.

Very well done and I'd like to wish you and your family a very happy new year.

Good luck with the cannon.

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A great looking job that shows talent and skills to be real proud of :good:

The glassfibre work was well done and I didnt see a mention of you getting stuck together with everything going :shifty:

most people do if its their 1st time useing it.

 

For any future glassfibre DIY'ers a tip on the glassfibre itch, wash in cold water not hot or warm , apply a skin lotion and refrain as much as possible from scratching, do not wear man made fibres on the itchy area.

Avoid applying resin or gelcoat in temperatures less than 10 degree's and preferably in a dry atmosphere, 5% resin can be added to the gelcoat top coat for a thinner application and smooth'er flow application if needed.

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Tested in terms of 3d modelled and the mechanics work when simulated and I have prototyped a very similar design for a different project in the past.

The design is also very similar but not identical to another punt gun that I have seen...

As I now plan to make the entire thing myself I will redesign it to suit the tools I have access to but fundamentally the release mechanism will remain the same.

Out of interest, what makes you ask?

 

I asked because it is a very simple design and I wondered how well it would stand a bump given the small engagement and position of the pivot point. I'm not implying that there is anything wrong with it, just curious.

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A great looking job that shows talent and skills to be real proud of :good:

The glassfibre work was well done and I didnt see a mention of you getting stuck together with everything going :shifty:

most people do if its their 1st time useing it.

 

For any future glassfibre DIY'ers a tip on the glassfibre itch, wash in cold water not hot or warm , apply a skin lotion and refrain as much as possible from scratching, do not wear man made fibres on the itchy area.

Avoid applying resin or gelcoat in temperatures less than 10 degree's and preferably in a dry atmosphere, 5% resin can be added to the gelcoat top coat for a thinner application and smooth'er flow application if needed.

Thankfully no, I managed to avoid getting stuck but i did get through a LOT of latex gloves and plastic cups to mix it in! As for the gelcoat, I had considered mixing resin in but i had heard from others that it can affect the colour meaning that each new section wouldn't match the last. As i don't have any experience personally i didn't know if this would have been the case. I'd be interested to hear your thoughts on this just in case i decide to build another one! ;)

 

I asked because it is a very simple design and I wondered how well it would stand a bump given the small engagement and position of the pivot point. I'm not implying that there is anything wrong with it, just curious.

Sorry, i didn't take it that way, I was more curious in-case you had any thoughts or could see something that could be improved (nothing is perfect!)

To be fair, there is a spring that is not being modeled in the images I posted that will help combat the point that you raise (springs are a pain in the a**e to model and don't compress properly when modeled so they play havoc with the FEA. It is a coil spring fitted between the flat bottom of the trigger piece and the base of the action so as to push the trigger into the grove on the firing pin

Edited typo...

Edited by Wildfowler
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Sorry, i didn't take it that way, I was more curious in-case you had any thoughts or could see something that could be improved (nothing is perfect!)

To be fair, there is a spring that is not being modeled in the images I posted that will help combat the point that you raise (springs are a pain in the a**e to model and don't compress properly when modeled so they play havoc with the FEA. It is a coil spring fitted between the flat bottom of the trigger piece and the base of the action so as to push the trigger into the grove on the firing pin

 

I think, if it was mine, I would have the pivot point towards the other end of the trigger and the spring in the position the pivot is now. This would give the spring more mechanical advantage to hold the firing pin. I would also relieve the diameter of the firing pin ( to the rear of the engagement groove ) so that the trigger engagement point couldn't drag along the pin and risk premature wear.

 

Perhaps there is something I have missed, these are just a couple of thoughts that may, or may not, be of use.

 

I look forward to seeing the project on here :good: If there is any small part that requires the use of a shaper let me know.

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both valid points! When i redesign it i'll look at including them!

I had initially put the pivot point where it is as i didn't want the trigger to move upwards when it is pulled, but similarly i didn't want to introduce a linkage point in the mechanism, but revision 2 will be vastly improved! :)

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I'm looking forward to it. The whole thread so far has been outstanding, one of the best I've read.

 

Have you decided what steel to use for the gun yet ? 4150 is used for rifle barrels, but you might be better with 4130 which is available in an easily machineable but still tough condition. It would save you having to heat treat it. I guess weight isn't a problem, so you can use whatever you like and size it to suit.

 

What a great project.

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I had planed on using EN24t which is AISI4340. Similar chemical makeup so similar hardness to 4150 but marginally less chromium (c0.1%) so slightly more prone to corrosion but a lot more magnesium (c1.75%) so a lot tougher and hard wearing.

4150 is good for rifle barrels as i believe they are hardened whereas the punt barrel needs to be tough as it will not be heat treated. Having said this, some other gunners I have spoken to have said that 24t is overkill for a punt barrel...

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  • 2 weeks later...

Unfortunately work has really been getting in the way of my play time recently and any spare time I get I've been spending with my boys, (teaching them to shoot!), so the whole project has slowed right down... I do search the internet for a lathe every evening though so as soon as one comes available at a sensible price I'll buy it, and as soon as I have that, gun production will commence! :)

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  • 2 weeks later...

Its been a long time since I did any work on the punt but managed to find a couple of hours at the weekend between shooting sessions to get a bit more done.

I managed to fit all 4 wash board extensions but then realised that the holes in the bolts i had bought to lock them onto the main wash boards were not in line so didn't fit them. I'll get some more tomorrow and fit them one evening. Once i have done this i can get on with making a ply cover for the 'cockpit' area so it can be stored outside if i need to.

 

 

 

 

 

 

These are the aft ones...

 

 

I will add another hook to hold the points in place

 

 

 

Edited by Wildfowler
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I have found a couple of lathes but all of them are up in the midlands or Yorkshire, it will cost me a fortune to get it back here. i'll give it a few more weeks of looking and if nothing has come up closer by then, i'll bite the bullet and get one and take a day or 2 holiday to go and retrieve it. I just need to borrow a trailer or flatbed...?

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  • 3 weeks later...

Yeah, possibly... I need to look into it more as my electrical knowledge is poor! Other people that have run this size machine on single phase all recomend an inverter but they are about £1200 whereas a single phase motor is £300... Apparently it runs smoother with a 3ph through the inverter? and also the inverter will have a soft starter on it as the full load current will be about 30A so the DOL starting current would be too much for a domestic supply I think...

Anyone with knowledge or experience of this I'd be please to hear from you! :)

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I`m not an expert but I was an electrican in a former life (before 30 yrs in the prison service) 30 amp would be ( at 746watts per horse power) 10 hp motor and starting current would be more, not impossible to install but your largest domestic fuse is 30amp, so you would need new circuitry, = expensive but maybe not £1200.

good luck mate it`s a lovely job.

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