UL folding saw

[Jan Rezac]

There’s been a discussion on lightweight saws recently, here’s my latest creation on that topic.

I’ve designed a 3D printed handle for the Silky Pocketboy 170 blade. The Pocketboy is a highly-regarded saw (made in Japan), but the complete thing is quite heavy at 220 g / 7.8 oz (according to specs I found online).

With my handle, the saw is 77 g / 2.7 oz. Almost two thirds of the weight saved. The blade locks in two positions as with the original, and the teeth are covered when closed.

There’s a couple of nice features included in the latest version. The blade does not protrude from the front end of the handle (in contrast to the original), so it’s safer to pack. The groove that covers the teeth is wider inside, so the teeth tips can’t touch the walls. I’m also thinking of adding a safety lock that will keep the blade closed (although there’s enough friction in the pivot to make that unlikely.

A prototype printed from PETG polymer is so tough I can’t break it with my hands. The final version is printed from carbon fiber filled material that should be stronger, so I printed it with thinner walls. It seems strong enough, but I haven’t tried a destructive test yet. Maybe there’s even some room to shave off a few more grams.

As to the performance, it cuts quite a bit better than the Fiskars folding saw that’s about the same size (it’s blade is 1 cm shorter) and weights 100g / 3.5 oz. Part of that may be also due to the Pocketboy having coarser teeth. The Pocketboy blade is wider, further weight savings can be made if it was cut down, but at this point I wanted a design that works with the stock blade.

[BlackHatGuy]

Very nice!

[bjc]

Wow!And what Doug said!

[David Gardner]

Now you’re talking

[Philip Tschersich]

Cool, I’ll take one for my Pocketboy.

[BlackHatGuy]

If you’re going to sell them, certainly let us know!

[john mcalpine]

There are times in my life when I realize I know very little.  This is one of those time.

You did an amazing job using a 3D printer that I know nothing about….and have never seen one.

[Jan Rezac]

If there’s interest, I may take some orders. But before that I’m going to do one more iteration of the design – the current one is fully functional and has all the features I wanted, but there’s still a couple of details that can be improved. Mainly in the hardware, such as finding a better spring for the lock.

The nice thing about the printing is that once the design is finalized and the printing process tuned on a couple of prototypes (especially when I’m trying to balance strength and weight), producing additional copies is easy. The main limitation is time – to make the set of parts for the saw, the 3D printer runs for about five hours.

And a general comment to the 3D printing. I had been interested in the technology since it became available to DIYers more than 10 years ago, but there was a lot of hassle around it (such as spending days calibrating the printer to get reasonable results). However, this changed a lot in the past few years. Now even affordable printer works almost out of the box and can produce nice results. More printing materials are available too, including ones with useful mechanical properties. So now it is mostly about finding real projects that can benefit from the technology – it also took me some time to accumulate meaningful use cases that can justify getting the printer. (If you want to go beyond downloading and printing toys from the internet, what must be more than 90% of the 3D printing market today.)

 

 

[Mike M]

count me in when you get it finalized :)

[Matthew / BPL]

I’d like one too!

[John K]

Nice design…count me in! Would love to lighten up my Silky.

 

[David Thomas]

Nice work.

Great weight savings!

Have you considered re-purposing jigsaw or Sawsall blades into a 3-D printed handle?  It looks like the blade-only for the Pocket Boy is around $20.  Versus $3 each for 9-inch Sawsall blades and $1 to $3 each for 3- to 4-inch jigsaw wood blades (which would be a really SUL option but nowhere near as capable).   My goto material for that has been bamboo flooring, glued together when I need more thickness, then subtractively working in the blade slot and finger grooves.

[Josh J]

<p style=”text-align: left;”>Very cool!  Wish I had my hands on a 3D printer again!</p>

[Eugene Hollingsworth]

I’m impressed. [ not that has any real value, I know. :-) ]   As backpackers we really don’t have efficient lightweight wood processing options.   “efficient”  / “lightweight”  pick one.

I like what you have done – the weight and the quality saw makes this a very viable option. The little Gerber-Fiskars slider saw comes in at 3 oz, but isn’t very efficient. A small campfire is always nice, and getting good enough wood to minimize smoke can be a problem. Currently I carry a SawVivor at 9.5 oz, or a Agawa Canyon Boreal 21″ at 19 ounces on short trips with lot’s of late-night down time because they can cut up so much hardwood with so little effort.

Your version could easily become a staple for longer multiday trips where I wouldn’t stay up so late at night.

[Kevin Babione]

I’ve started carrying a saw on my trips again to help with blowdowns on the trail and firewood in camp.  My last trip I used a Gerber Sliding Saw, which was okay, but not great.  I just bought a new saw that I’ll be carrying this weekend (thanks to David Gardner) and I’m looking forward to trying out its 11″ blade while only carrying 3.35 ounces (in its sheath).

@Jan – It would be ideal if you could find a supplier in the states who would print, assemble, and ship them for you.  I’m guessing you’d be able to sell a lot of the handles from the interest posted so far.  I’ll add my name to the “I want one too” list.

[Eugene Hollingsworth]

Kevin – that’s an excellent idea:  “@Jan – It would be ideal if you could find a supplier in the states who would print, assemble, and ship them for you.  I’m guessing you’d be able to sell a lot of the handles from the interest posted so far.  I’ll add my name to the “I want one too” list.”

 

[Chris R]

If you are going to make a lot of the same design perhaps it would be better to look at making a mold and injection molding the handles? May even be cheaper/quicker to CNC machine the handles from a solid block.

[Jan Rezac]

Hi everyone. I didn’t expect so strong response. Where’s the UL ethos that commands you to leave all gadgets home and use your teeth instead! :-)

First, an update on the project. I’ve fine-tuned the details I wanted, and now I’m just waiting for an order of stainless steel hardware. I’ll post some more pictures once I’ve the next version assembled.

Second, the business side, or the lack of it. I can print  a small batch for fellow BPLers on my printer, and the assembly does not take much time. Made out of the premium carbon-filled material I got for my own copy, I’d ask about as much as the blade costs plus shipping. Actually, the shipping may be the main obstacle, as it is overseas from me to you. The thing is light and relatively flat, so it may fit a letter tariff that won’t be too expensive, but there’s still some paperwork around it.

At some point, I will likely release the files so that anyone can print it himself or get it printed by a friend. It works well enough printed out of the PETG material which is now a mainstay. Anybody with a printer may already have some around. It could be as strong as the original at the cost of being only a little heavier. (The material I’m using is stiffer, and has a better surface finish, but the difference is too small to invest into it for an one-off job.)

Someone suggested going big with mass manufacturing. I’m not in that business, but I know that only setting up injection molding would cost a few thousands dollars. There’s hardly a demand that would pay that.

Moreover, the 3D printing is quite important for achieving the weight this low. The main part where most of the volume is is printed as a surprisingly thin shell with a honeycomb supporting structure inside. Only the most stressed regions are selectively made solid all the way through.

 

[Mike M]

I’m still interested :)  Might be worth checking on what postage would be to the US; like you said a couple of ounces and flat shouldn’t be terrible

[Ben H.]

This is great Jan. You could think about uploading your model and selling them through something like Shapeways: https://www.shapeways.com/

I’m not sure if they have the material you use, but I found them pretty cost effective for small 3D printed items. It looks like they have tools for small sales like this where people could buy them from a link you set-up and you would get a predetermined profit. I guess the hard part for people would be sourcing the pieces of the hardware individually.

[Matthew / BPL]

Jan, I have a printer with a 160x160mm bed. What’s the maximum dimensions of the finished piece?

I have PETg. I haven’t printed since my classroom closed last March but I could go grab my printer and bring it home. I’ve only printed with PETg once or twice and had some problems with layer adhesion that I’ve been meaning to troubleshoot so this might be a good opportunity to try that.

[BlackHatGuy]

I imagine that those of us who are interested could perhaps do a ‘group buy’ so that you only have to ship one box to the US, and then we could split it up from there.

[Matthew / BPL]

^that’s a good idea

 

[DAN-Y]

David Thomas, I have a folding Milwaukee with a modified wood blade(6″) that works well for 2″ limbs. Looks like this when folded:

[David Thomas]

Dan,  That 6-inch-blade Milwaukee looks like it would be fine for small stuff and yet quite comfortable to use.  My most common use to impromptu trail clearing of 2-3 years of alder growth, so 1-2″ stuff.

And if I’m collecting firewood, I go for the dead, dry spruce branches still on the trees which are 1″ and smaller.

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