Forum Index » Editor's Roundtable » The Evolution of a Winter Stove - Part 3


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Daniel Tetreault
(dant8ro) - M
Kickstarter? on 07/20/2013 08:02:09 MDT Print View

Hi Roger,

I've been following your series on BPL for a while now. I'm excited about trying the stove out in the Canadian shield. I do some winter camping and have a lot of camping buddies that are pursuing every last gram.

I know you're still in development, but has Kick Starter crossed your mind? You could set your threshold at enough to cover the cost of all the production level tooling to pump these babies out + whatever other expenses you need per stove to get it done.

I'd be in for a reward level that includes a stove and brings you one level closer to production.

Dan.

Edited by dant8ro on 07/20/2013 08:10:40 MDT.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Kickstarter? on 07/20/2013 16:35:23 MDT Print View

Hi Daniel

> I'm excited about trying the stove out in the Canadian shield. I do some winter camping
You need to email me direct with some details.

> has Kick Starter crossed your mind?
Actually, it never crossed my mind. At present it's a hobby,(albeit a shade odd) but Kickstarter would change that a bit too much for my liking at present. If the stove turns out really popular I wouldn't need the Kickstarter funding; if it isn't then I don't want the hassles of a Kickstarter failure. I have the CNC, and it is a very rugged unit able to handle the workload.

Cheers

James Haithcock
(ke4amp) - M

Locale: Southeastern US
Thanks for the articles on 07/21/2013 06:49:16 MDT Print View

Great articles. If your keeping a list I would be interested in the FMS-300T.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Update on Legs on 07/23/2013 04:40:30 MDT Print View

Hi all

I have spent a couple of days experimenting with a modified design for the legs, and especially for the pivot in the middle. Up till now the stove body and the canister connection had been my main focus. Understandable (imho), but that meant that not enough R&D had been done on the legs - up till now.

A casual observation on my desk while fiddling with a stove gave me an insight into how or why the stove 'wobbles' under load. This led me to see that a huge improvement was possible by adding a simple titanium washer in the right place. After all, adding titanium is always good - right? So I did the experiment, and it works great.

The 0.8 mm thick 'tripod' legs are made of a good alloy (5251 H34) and it seems that the only 1 mm sheet locally available is made from a lesser alloy (5052) which is not much stiffer but is a lot harder to machine cleanly and at speed. For the present I will probably use the good 0.8 mm alloy, as it now gives good stability.

At the same time I will modify the design of the legs themselves just slightly, to create an 'opening tab' at the outer corner. When the legs are all folded together it can be a problem separating them out again. The little tabs at the outer corners are now bent apart so the legs open easily.

As a result I think I will probably withdraw the 'centre support' design from production. If the centre-support legs get at all bent the stove can and will rock. My thanks to several readers who pointed this out to me: you were right. I will upgrade all stoves to this new and better design.

Cheers

Alan Bradley
(ahbradley)
Congratulations on the valve and stove design on 07/23/2013 15:32:31 MDT Print View

Congratulations on the valve and stove design.

Your valve seems very clever: could it become a new standard for commercial stoves?

Could you license it to manufacturers?

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Congratulations on the valve and stove design on 07/23/2013 16:31:24 MDT Print View

Hi Alan

> Your valve seems very clever
Um ... I am going to guess here that you are referring to the shut-off valve in the canister connector, not the one in the stove body.

> could it become a new standard for commercial stoves?
> Could you license it to manufacturers?
It would be nice to think it could be widely adopted, but it adds complexity to the manufacture. Never mind the improved safety and control - that jacks the price up. Would any of the Western stove 'manufacturers' or their Asian factories pay me for the rights?

I may be getting old, but I can't help being a shade cynical. The best ideas for those guys are the pirated ones they don't pay for. Mind you, I am open to any approaches.

Cheers

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: Congratulations on the valve and stove design on 07/23/2013 16:42:05 MDT Print View

Roger,
Not only cynical, but complacent.

You should close with "I'm just waiting for a deep pocket company to rip it off so my lawyers, willing to arbitrate on a contingency basis, can negotiate a fair and equitable deal for all."

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Congratulations on the valve and stove design on 07/23/2013 22:18:17 MDT Print View

>You should close with "I'm just waiting for a deep pocket company to rip it off so my lawyers,

One does not have to tell them everything in advance...

Mind you, MY idea of 'a fair and equitable deal' might differ slightly from theirs.

Cheers

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: Re: Re: Congratulations on the valve and stove design on 07/23/2013 23:25:16 MDT Print View

Presumedly, you have put a defect in the publicly released version that will cause it to explode occasionally.

You'll only release the good version if they give you fair and equitable deal.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Re: Re: Congratulations on the valve and stove design on 07/24/2013 04:13:23 MDT Print View

> Presumedly, you have put a defect in the publicly released version that will cause it
> to explode occasionally.

Yup. Embedded quantum-spin-based microprocessor chip with an encrypted WiFi link to the BPL membership database. As long as you have a valid membership, the chip stays quiescent and the 2 grams of C4 remains inert. However, if the chip fails to get a valid membership reply about 3 times, it becomes a temperature sensor. When it detects body heat in close proximity ...

Cheers

Alan Bradley
(ahbradley)
Re: Re: Congratulations on the valve and stove design on 07/24/2013 06:42:30 MDT Print View

>>>> Your valve seems very clever
>>Um ... I am going to guess here that you are referring to the shut-off valve in the canister connector, not the one in the stove body.

The shut-off valve is a clever feature for remote stoves with the main control at the burner, but I was mainly referring to the ability to cope with both screw-on and camping gas cartridges. This would seem useful on any commercial stove, even remote ones with conventional heat adjustment at the cylinder end.

Thus the multfit connector would seem worth making available to others/manufacturers: on terms acceptable to yourself.

I have decided remote stoves are better: and have merged my can-top with a brunton stand, however, I still like meths :-).

Edited by ahbradley on 07/24/2013 06:52:31 MDT.

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
The Evolution of a Winter Stove - Part 3 on 07/24/2013 06:57:59 MDT Print View

I see that you have upgraded the stands. Great News! I was sort of wondering about that. Stainless is heavier but not really that much stiffer (unless well tempered.) Stoves like the Simmerlight/Windpro didn't seem all that floppy. But, I am guessing this add-on bit will require occasional adjustment, and/or loctite. Lighter is usually better when well designed.

I was thinking about the brass nut locking the FM-300T burner on. A small seat could be milled into the body letting you remove it. A fairly precise distance between the jet, air inlet holes and seat could be maintained that way and it might save a few grams of brass. This might require some clearance for the bottom of the threading on the burner body/mixing chamber though.

Well thought out!

Stuart R
(Scunnered) - F

Locale: Scotland
Re: The Evolution of a Winter Stove - Part 3 on 07/24/2013 15:07:09 MDT Print View

Very nice work Roger, I particularly like the versatility of the canister connector. Availability of canisters in small villages in the remoter parts of Europe is a bit of a lottery.

Brian Jones
(jonesbr) - MLife
Conversion to a hanging system? on 07/25/2013 19:21:03 MDT Print View

Great work, Roger!

Your stove looks like just about everything I've looked for in a remote, inverted canister stove.

The one place where a more traditional upright canister stove would seem to have an advantage is in its ability to convert into a hanging system for use inside a tent.

Looking at your design:

1) Is the fuel tube long enough to reach a canister hanging just below the pot legs?
2) would it be possible to add notches or something similar to the underside of the pot legs such that they could retain the rolled lip of an inverted canister? (A wire "basket" anchored off the legs would likely be simpler, if less elegant. Or maybe a rubber/silicone ring that could slide over the inverted canister with small holes that would allow clips to connect it to the legs...)
3) If you tried to suspend the setup by running your suspension wires to the outermost cutouts on the legs (likely using a spreader bar or two on the wires), would it be stable enough if you had the weight of canister hanging below it? (Worst case would obviously be a full pot and empty canister, and I suspect that it might be too unstable.)

This may be a level of flexibility beyond your interest, but it intrigued me, so I thought I'd ask.

Thanks!

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: The Evolution of a Winter Stove - Part 3 on 07/25/2013 22:22:45 MDT Print View

Hi James

> I am guessing this add-on bit will require occasional adjustment, and/or loctite.
In theory, no.
The nut which clamps all this together is done up tight against the end of the leg pivot. This means the nut should never loosen, despite the legs spinning wildly. There are low-friction brass shim washers to cut the friction and prevent galling, so there is negligible torque on the nut anyhow. The stainless steel grub screw which holds the nut is jammed in place rather tightly - it does its own thread forming in fact.

> the brass nut locking the FM-300T burner on.
Yes, I wondered about this too. But the weight of the nut is actually very low, and it serves TWO purposes. First of all it locks the burner onto the stove body so it does not accidentally unscrew and fall off. In addition, it allows me to align the pot supports on the burner with the heat exchanger coming up from the stove body. In theory I could adjust the start angle of the thread to do this by itself, but if they change the start angle on the burner column with respect to the pot supports during manufacture I would be in trouble. In practice, I don't think that angle is even controlled during manufacture.

The change in position of the air holes with respect to the face of the jet would be at the most slightly under 0.2 mm for the worst case alignment. The distance between the air holes and the jet is around 7 mm. Methinks I will not worry.

Cheers

Michael Driscoll
(Hillhikerz) - M

Locale: Monterey Bay
Roger stove ? on 07/26/2013 10:54:59 MDT Print View

Did not see this in the thread so far but was wondering if an upside down Coleman canister with adapter will work with this stove... Or is that just crazy thinking...

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: Re: The Evolution of a Winter Stove - Part 3 on 07/26/2013 12:25:35 MDT Print View

"The nut which clamps all this together is done up tight against the end of the leg pivot. This means the nut should never loosen, despite the legs spinning wildly. There are low-friction brass shim washers to cut the friction and prevent galling, so there is negligible torque on the nut anyhow. The stainless steel grub screw which holds the nut is jammed in place rather tightly - it does its own thread forming in fact."

Yeah, I can see where that would work. It occured to me that the Simmerlite pot stand was actually connected at the top, too. This adds a considerable stiffness, overall, to the stove. I am sure you have it well in hand.

Yeah, the alignment could get to be a problem around the heat transfer bar. Not as clean as I thought. Thanks for pointing that out. How do you align the Fm-116 burners? I am guessing the upper nut on the FM-300 is adjustable, also.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Roger stove ? on 07/26/2013 16:19:11 MDT Print View

> wondering if an upside down Coleman canister with adapter will work with this stove
There are two sorts of Coleman canisters: screw-thread and Powermax. BOTH work without any adapter being needed.

The hair-spray style with a spray jet on top does not work, but they only have butane in them - not suited to winter use.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: The Evolution of a Winter Stove - Part 3 on 07/26/2013 16:22:40 MDT Print View

> How do you align the Fm-116 burners?
I only have a few of them, so I took some care with the CNC and the start angle for the thread on the stove body. A very thin shim can also be used.

> I am guessing the upper nut on the FM-300 is adjustable, also.
It is usually done up tight. It holds the pot supports in place. Best to leave it done up tight. I guess you could spin it off, machine a gram or two off it, and replace it.

Cheers

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: Roger stove ? on 07/26/2013 16:29:32 MDT Print View

"The hair-spray style with a spray jet on top does not work, but they only have butane in them - not suited to winter use."

But, the boiling point is 32 F or whatever. If you put it in your pocket you can warm it up and use below 32 F. With your stove you don't get evaporative cooling so you should be able to use it as long as contents are above 32 F.

If a canister is 2 ounces, fuel 2.75 ounces, your stove is 3.5 ounces - total 8.25 ounces - enough fuel to boil maybe 11 pints. That could be a good option for many trips.