Home made Enders pump cup assembly

With the news that Sefa was no longer making Enders pump cup assemblies any more I decided to see how easy it was to make one myself.

Materials and equipment:

2x 10mm stainless washers
Long brass eyelet and end brass washer
Eyelet crimping/swaging tool
14mm leather pump cup (mine was intended for a bialaddin lamp)

The order of assembly is as follows:



Assembled and ready for crimping it looks like this:





Placed on the base of the crimping anvil:



This is the crimping tool:



And the finished assembly crimped and ready to use:







This was soaked in oil for a while while I placed a new Viton O ring on the pump shaft:



These are larger than the ones found in @Russenjesus set as you can see here:



...but they fit on the shaft and form a good seal with the end of the new pump cap assembly:



I pushed the new pump assembly to the end of the shaft so you can see how the Viton O ring fits and how is mates with the brass eyelet. There is roughly 1mm play to allow the air to escape on the backward stroke. The thin end of the pump shaft that the new washer assembly fits over is roughly 4.5mm and the inner diameter of the eyelet is 5mm which gives enough play for the new pump washer assembly to move up and down. Here is a photo showing the retaining nut in place. I have tried the new assembly in my converted roarer Enders 9061D and it worked exactly as the Sefa model that it replaced.



My only concern is that the washer at the bottom is not wide enough to provide a solid base to prevent the leather folding back, but I didn't have a wider one handy. However, having used it and checked to see how it performed it seems OK.

Finally a flame shot using the new pump assembly to show that it works. I gave it a good number of pumps to make sure it could handle the back pressure which it did.




Here are some links to the parts I purchased on eBay:

https://www.ebay.co.uk/itm/Metric-Viton-Rubber-O-Rings-2mm-Cross-Section-2mm-30mm-ID-UK-SUPPLIER/141455807170?ssPageName=STRK:MEBIDX:IT&var=440603745988&_trksid=p2057872.m2749.l2649

https://www.ebay.co.uk/itm/4mm-14mm-Long-Barrell-Eyelets-Grommets-Washers-Banner-Leather-Belts-Bags-Canvas/292540093411?ssPageName=STRK:MEBIDX:IT&var=591361068762&_trksid=p2057872.m2749.l2649

https://www.ebay.co.uk/itm/Eyelet-Punch-Die-Tools-Kit-For-Leather-Craft-Plier-Grommet-Set-Clothing-Fabric/142017573426?ssPageName=STRK:MEBIDX:IT&var=441123095807&_trksid=p2057872.m2749.l2649

I also ordered some of the other O rings from the same source to provide a seal between the pump tube and the tank, and for the filler cap...

https://www.ebay.co.uk/itm/Metric-Viton-Rubber-O-Rings-2mm-Cross-Section-2mm-30mm-ID-UK-SUPPLIER/141455807170?ssPageName=STRK:MEBIDX:IT&var=440603746249&_trksid=p2057872.m2749.l2649

https://www.ebay.co.uk/itm/Metric-Viton-Rubber-O-Rings-2mm-Cross-Section-2mm-30mm-ID-UK-SUPPLIER/141455807170?ssPageName=STRK:MEBIDX:IT&var=440603746141&_trksid=p2057872.m2749.l2649

I hope this helps fellow Enders owners who need replacement seals and washers and might be considering making their own.

Colin

 

As an experiment, I crimped a brass washer on its own. Interestingly, the tubular shaft rolls back down over itself as you can see here...

 

Very well done - thanks sharing in such great details!

 

Nice work and locating the necessary parts.
Duane

 

Hi @Colin Geer Great post, with lots of photos and links, and impressive Enders pump pistons.
Best Regards,
Kerophile.

 

Very nice, and well presented. Are you planning on going into production? With Sefa retired from the business, there is a demand and niche market for this type of pump cup.

Paul

 

Excellent Colin.
Similar design used in the Australian Companion stove. I will give it a try.

 

@Colin Geer

Well done and well presented.
It is good to find others who are willing to think outside the box.

I do miss Sefa's pump cups and I only have a few left.

Thank you for sharing your home made Enders pump cup assembly with us.

Norman

 

I was wondering if anyone would want me to make more and sell them. I'll have to price up correctly sized leather cups as I have no idea where the one I used actually came from! But in principle I'm good to sell them to interested enthusiasts. Issues will be finding consistent leather cups and testing that the assembly is durable. If anyone knows a good source of leather cups at a reasonable price I'll have a better idea how feasible going into production will be.

If anyone thinks they might like to purchase one or more, PM me so I have some idea of the interest.

Colin

 

Colin,
I see you was faster as I;-)
I had the same idea, but I would make the leather myself and I would crimp the brass washer by an electric rotating tool for a better result.
So I can buy the leather at you;-)

Markus(RJ)

 

Base Camp:

2261 Pump leather to fit brass carrier on stoves 00, 96, 111, Primus 210. £ 2.30 or £3.95 for 2

 

Wow, so how do you make leather washers and how do you make them stay in a cup shape? Also, what do you mean when you say an electric rotating tool? I can get one if they're not too expensive, although the crimping tool worked OK.

This one was really just to test if I was able to make one myself and I can, but to make them for other people I need to take it a bit more seriously!

 

Thanks kerophile, I'll look into those and for making onesie-twosies for my own use they would be fine but in large numbers I'm not sure. I'm looking to reduce the leather washer to as close to £1 as I can manage although that might reduce the quality so I'll have to shop around. As ever you find yourself looking for excellent quality at rock bottom prices and that's always going to be difficult!

 

Hi @Colin Geer please see this thread:

https://classiccampstoves.com/threads/making-pump-washers.4061/

About the same time, I wrote this:

Hi, I have two great jigs for making pump leathers, which good friends have gifted to me.
They work very well and I have successfully made many washers in the past.

I have found that the choice of leather thickness is fairly critical:
Too thick and obviously it will not fit the dimensions of the gap between the holes of the jig and the insertion tool.
Too thin, and although you are able to push the leather into the jig the side walls end up with "pleats" rather than the smooth surface desired.

It is also helpful to have the centre hole of the leather "blank" present before you make the cup washer as it can be used to "centre" the washer on the male tool during the forming operation.

I believe that the ideal thickness fo pump leather is around 1.4 - 1.5 mm dry thickness for half to 1 pint stoves, and 1.8 mm or so for larger tank capacity stoves.

Quality of leather is also important as there is a lot of rubbish "leather" on the market nowadays. Some has a highly-polished, almost glazed surface and other types are in fact plastic coated. Neither of these types are suitable for making decent washers.

You do need proper tanned leather, probably not heavily dyed, with a natural rough finish on one surface. This will form the working surface on the completed bucket washer.

I live in a remote area. We do have one traditional cobbler, and he is helpful, but it is still difficult to get exactly the leather I need. I guess that now all EU footwear seems to come from China I should not be too surprised.

Best Regards,
Kerophile.

 

Hi, I have a concern, where is the by-pass for on a pull back.
https://classiccampstoves.com/posts/138209/

 

Hi JP2. The Enders pump cup arrangement is a little different from most other stoves. With the Enders system, the whole assembly slides back and forward on the end portion of the shaft and only seals against the rubber O ring when it is pushed forward. On the back stroke, the assembly slides to the end of the pump rod and air passes through the ring shaped rivet or eyelet as it's sometimes called. On my home made pump assembly, the eyelet has an inside hole diameter of 5mm that fits over the narrow end of the pump shaft which is roughly 4.5mm, allowing a gap of .25mm all around the shaft for the air to escape although it is almost impossible to see this detail in my photo.



I hope this answers your questions. I know that my pump cup works as I've already fitted it to one of my Enders stoves and it successfully pressurized the tank.

 

I didn't know, thank to teach me. Now I have to buy one to know more I guest . Lolo

Can we see the hole? Sorry I am visual

 

Hi JP2... here is a photo of the 5mm hole in the centre of my home made pump cup assembly. The shaft of the pump is only 4.5mm so there is plenty of gap for the air to escape on the back stroke.

 

So JP2, do you have an Enders stove? They are great stoves, very well engineered but maybe a little too complex with many parts and like the pump washer, everything is a bit over the top! I now have 2 and I love them. They run on white gas/unleaded auto fuel/naptha based fuels so you need to keep them well maintained. They are a little similar to the Optimus 111B but with maybe 20x as many components!

 

Look like interesting stove but by where the air escapes on the other side of the pump on a pull back. Lately I have discovered where the air by-pass was on a pump as one of mine was plugged and it is why I was concerned to find out where It was on a Ender.

NOW, sorry if I don't see it and here, as a example, is the one plugged and unplugged on one of mine.
BTW I like your cup, are they the same size of the one on a 111?