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finnleo

Simple chair out of wood. (Update: Evolution version)

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finnleo

Well, its been awhile, but I believe I've finally come to a semi decent solution to make a repeatable small simple scandi-type stool ... the chair type of stool that is.

 

The solution to my headache came about looking over some of the accessories that came with my Dremel, which I initialy thought was pretty hopeless, but suddenly the idea popped up to try the routing accessory in this application.

 

the main problem was that a full size top router was a bit too... aggressive to say the least when trying to do fiddly and thing pieces like this, so I thought it was worth a try.

 

Hence a proof of concept was made up:

 

17073912130_58e50beda2_c.jpg

wood055

 

The prototype was a quick bash together from plain 18mm glue board stock, that I had laying around. As prototypes go it showed the problems, and minor hick-ups with measuring the tools to use with the router.

 

But even so, what I had initially measured to work with a DD sized doll, turned out better suited for a MDD:

 

17073912750_fffa268f82_c.jpg

wood056

 

So after re-calibration it was time to think of version 2.

 

This time I thinned the glue board to about 12-14mm, for A), it would be closer to scale with the item I was modeling it on, and B) with the proto the least hastle with the dremel would be to cut through the wood in one pass, to minimize post clean up work.

 

The main idea is two pairs of legs, with the circular bit screwed on to where they criss-cross.

 

It all starts with routing the outer line of the leg piece, to measure the tool, keep in mind its the distance from the edge of the routing guide on the machine to the edge of the routing bit that will be the offset needed.

 

I'm being a bit of a mean old bugger about giving the measurements, since im not yet 100% happy with the results.

 

17077156190_944fb43ec5.jpg

wood057

 

After attaching firmly the guide block to the piece, it was time to let the router do its thing:

 

17264173541_dee82e557e.jpg

wood058

 

On this pass its not too crazy about being neat with the tool, since the outline comes from pressing the machine into the tool. The round edge of the routing shroud gives a radius on the edge on the tool, as standard.

 

Then we are 25% done with the legs:

 

17077158020_c599ef7e07.jpg

wood059

 

Next comes the smaller guide tool, for which you need to keep in mind also the width of the routing bit when calculating the offset needed for the guide piece.

 

This is however where you need to be rather neat, and keeping the router firmly against the guide tool, since if it drifts away from it, it most likely will ruin the piece you're trying to make.

 

17077158790_4a45a06a96.jpg

wood060

 

The circular bit was routed using a suitably sized hole-saw offcut I had laying around from modifying my shelves recently:

 

17262921302_bdc8cea052.jpg

wood061

 

Then we need to notch the leg pieces so they go over each other underneath the circular piece:

 

16642259814_6351b33365.jpg

wood062

 

Check that the two pieces end up flush with each other, and drill a hole in the middle of both:

 

16642260784_b314a5eff5.jpg

wood063

 

Add one screw to attach everything together, and we should have something that resembles this:

 

17077163540_4c3280462e.jpg

wood064

 

And speck testing for scale:

 

16644486013_222b9d6893.jpg

wood065

 

Its a bit rough and tumble, and flimsy with its legs, but still manages to keep a DD sitting pretty.

 

 

Production update

 

So its time to kick this topic up a bit, because of a few reasons.

 

Mainly the first was the longevity of this first edition chair, and it did make it for two years... until this happened:

 

33233674242_9d5b076986_z.jpg

rin040

 

yes... Rin broke the thing, and she hasn't had a photo session since..

 

Ultimately I was a bit torn between thoughts of annoyance that it did break, and also that it had actually made it this far.

 

Now one year later I finally got around to replacing it, due to various reasons related to motivation and whatnot other aquirements.

 

namely this summer I managed to invest in a few tools that had been on my wish-list in terms of wood-working to make things easier and less... dangerous.

 

The first was a CNC router which I thought would have been the obvious answer to making these by the dozen, but unfortunately this thing turned out to be more suited to engraving than milling wood, so while it technically could do it repeatedly, it took hours to make a set of legs, if the routing bit wouldn't have broken before getting to the end.

 

So while this initial purchase was a dead end, the second piece of equipment would be essential to get this done with it in the first place, and that was a planer to thin the 18mm thick glue-board into a more suitable thickness.

 

But finally I came to the conclusion of trying to build the guides for my sketchy routing table to be able to expedite the making of these pieces.

 

hence, these were born:

 

29259552237_b6d8a6e50a_z.jpg

wood151

From left to right:

The raw cutting template, the outer perimeter guide, and the inner perimeter guide.

 

So as the names would suggest, the template is for marking out the raw pieces with a modest allowance of material after which the piece would be screwed onto the first jig and routed, then put in the other jig and routed the second time.

 

So that's the theory, so how's it in practice?

 

So I tweaked the initial raw leg pattern to be able to zig-zag the pieces from the piece of wood they would be cut from, but this provided some amusing drawbacks with the size I had to work with, which were off-cuts from my shelving project...

 

29259552177_3be2971047_z.jpg

wood152

 

So no matter how I tried id end up with some wasted material, but I wasnt too annoyed since this was re-purposed in the first place.

 

and after a minor session with my little band-saw I had these to show for:

 

44148170992_7481204cd7_z.jpg

wood153

 

So nothing to it but to screw on the first guide, and proceed to make the first cut:

29259551887_1bbd950a14_z.jpg

wood154

 

As the tooling suggested, the router uses a follower bit that follows the contour of the piece on-top of the workpiece.

 

a few repeats, and re-purposing the old stool's top piece to cut the new one's, I had this to show for:

 

44148170592_3874a2fb9f_z.jpg

wood155

 

I initially thought I could just start the second routing right away, but it turned out that I had to make another relief cut on the band-saw if I didn't want everything to end in tears, as the pine is so soft it just shatters if I took a bigger cut with the router.

 

29259551667_221a1c9dbe_z.jpg

wood156

 

 

So using the second jig I marked the relief lines:

 

44148170082_8af055ecef_z.jpg

wood157

 

and a few moments later they were ready for the second routing:

29259551257_cd39683415_z.jpg

wood158

 

and in relatively no time they were almost done:

29259550927_439b74203b_z.jpg

wood159

 

The final tools to be made were the templates for the notches at the top to allow the pieces to criss-cross beneath the seat base, and there was a minor offset since the resulted thickness was a bit of an odd number.

 

44148169622_4e9dc0731e_z.jpg

wood160

 

The pieces had to also be done in pairs so the fitment is still a bit custom, but I suppose I had to leave some extra bother into this...

 

So in the end I was getting up to a good speed, before my band-saw blade decided to say, "PinG!" .. and thus ground my work to a halt.

 

But before that I managed to make three complete chairs, and I still have materials to make three more, not to mention the ability to ... well, make even more if I need...

 

44148169192_450c2d6f6e_c.jpg

wood161

 

But that's it for now, if all goes well the final number of chairs might be seen in a photo-set some time soon, or as it took a year to remake this, maybe not so soon after all...

 

Evolution theory.

 

Well, as things would have it, I did have some other plans with this general design for a higher bar-stool type deal (since the real life version did come in this flavor also).

 

So today with the aid of some questionable 90's german fem-rap I whipped up the tooling to make that happen in a repeatable fashion also.

 

And because I managed to survive with only minor injuries, the first one to come out was quite nice, despite only having a quick once over to sand off the rough edges...

 

47134820912_91c4a37e44_z.jpg

wood173

 

Melty giving it a test...

 

47134821732_4707520e93_z.jpg

melty061

 

Now to pump out half a dozen of these...

 

Thanks for looking, and see you next time...

Edited by Guest
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sleepywolf

Hey, that's neat! Really like the second version - all the parts seems to be a bit more in proportion to each other.

 

You said it's a bit flimsy - do you mean the legs are flexing? I'm by no means a wood working expert but I wonder if perhaps the legs would be stronger if they were cut along the wood grain rather than across it.

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finnleo

There is some little wobble, but that's more to do with the design, and could be helped by using four attachment screws instead of one.

 

I do remember contemplating about the grain direction, aesthetically it would be better to cut lengthways, but figured it would be stronger like this at the bend where it goes under the seat base.

 

The original real life design is made from plywood, so that does not have to worry about that... but dunno does a DD weigh enough to be an issue.. might have to test one day when I get more stock to play with.

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Sister Kyoya

I was also wondering about using plywood as well. It could even be done from layers of cardboard too. (I have a ton of that stored for DD projects.)

 

Frankly this is really awesome! I finally pulled out my Dremel the other day to sand down the DD boobs so they weren't so indecent and was wondering what else I could do with it. This could also be done with a jigsaw as well.

 

I think it is really cool how the legs are done, and the same concept could be used for a bench I think. Just take the 2 leg pieces (without the notch) and have them going the same direction and put them on the far ends of a rectangular seat. I wonder if it would be possible to add a back by making two other pieces similar to the legs, but in an 'L' shape instead of a 'U' shape to attach a back. Most likely this would mean that the individual leg pieces would need to be wider (and stick out the back a little) to make the bench not fall over when its empty. (I hope my rambling makes a bit of sense...)

 

I think you have done a great job Finnleo! thank you so very much for sharing.

 

~Sister Kyoya


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finnleo

For a backed bench, id probably try to make h-shaped legs on the sides.

 

but that would require a bit more complicated guide tooling to be made with a router, especially if you'd want the back to be at another angle than 90 degrees, but theoretically its possible.

 

but it all depends on how many someone wants to make of something, the router approach is mainly to get semi-constant repeatable results, for a one-off id probably use a jigsaw and sander to tune up the bits.

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sinclair

This is a great idea, and I love how they are stackable. Not sure how I missed this before, but it did all happen before I joined the hobby and forum.

 

Question about your CNC router, were you trying to do it in one pass, or was it multiple passes? As having a background in machining, and laser cutters/engravers , the quickest way is to make a bunch of fast shallow passes instead of one slow deep pass. So try like 8 passes at 10 times the feed speed. So in a quarter inch thick piece of wood cut only a depth of 1/32 of an inch at a time. Spin the bit near it's top speed and feed it really fast. Of course this only really works if your CNC can control the depth of the tool. If you have to set the depth for every pass, then it probably won't help much.

 

As for the direction of the wood grain, you are screwed in either direction when it come to shear (The force the legs will experience when the stool is slid along the ground.). Using a layered board (Like plywood.) would give you the best strength. This is why the peopled sized ones are made with either bent wood or layered wood.

 

And Illya!! In her PE outfit!!! I still need to get that for mine.

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finnleo

@sinclair

 

mmm, this is an old thing that I revisited, partly due to learning to do stuff and implementing the techniques I learned for instance from my bar stool set...

 

The plywood was already discussed, and it would be heaps better, but I dont think it would look as nice at this scale, and also I would actually have to buy it specifically, whereas here i used scraps from after making custom ikea Ivar pieces.

 

Though the planer now allows me to make my own glue board, from for instance fig spruce of which I have a bunch of wall paneling I took down which would have a finer grain and is a bit more sturdy in general.

 

Dont take this the wrong way, but the CNC-machine setting suggestions are a bit amusing since you didnt really ask what kind of machine it was at first...

 

39060050002_8f8dc19291_z.jpg

electro035

 

Its not really a "big" machine, but one of these tabletop things I think an american designed as an open source project type deal, that the chinese sell as a Ebay kit en masse.

 

Its not totally hopeless, but you really need to be aware of the feedrates and depth of cuts so you dont bend or prematurely wear out the whole y/z-axis sled. Especially with the long routing bit I only had at my disposal at the time of the first try, which physically bent while doing the work at even the modest feed/depth settings.

 

But while being dinky it can still do this sort of thing for which I have some ideas for with other materials:

27313274069_11aea2b016_z.jpg

electro040

(afer this first thing I've since changed for a collet chuck just so you know...)

 

G-code Programming software is my biggest issue though, since for a few reasons I don't like the idea of autocad's fusion 360 cloud system and the eula which states that everything you design is basicly theirs, and only for hobby use.

 

I've since gotten shorter tools, but I've yet to try them out, mostly because I havent had the planer to easily make the wood thin enough to route. Also upgrading the spindle is one way to get more oompf, but I am looking at more sturdier kits that could allow for some more aggressive passes... if I had money that is.

Edited by Guest

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sinclair

From what you said before my reply, and from what I have played with, I pretty much imagined what you just posted a photo of. You said you had other bits, as the one bit that's in the photos is an engraving/marking bit and not made for cutting. How big is the collet? Are you able to use Dremel bits? How fast can it spin the tool? Or do you have a link to the CNC? I know what you mean about the EULA, Autodesk always seems to go overboard. Depending on how geeky you are, there are some free open source G-code programs you could try using instead. Although G-code is just a programming language, so technically you can use Notepad to write a program, but that is way outside my ability. At my last job I used a Mastercam plug-in in SolidWorks. I know a guy that has a CNC mill version of yours, so I can ask him about the software he uses if you'd like.

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finnleo

I have a collet set that goes from 1 to 7 mm, but the cheapo chuck that came with the machine can actually hold dremel bits right away, since its for 3mm axle items.

 

For my first efforts I only had the rough dremel routing bit that you could see in the older pictures in the dremel, but that was way too long and caused the bending issue and finally snapped, I knew it wouldnt work, but I just had to try .. just because violence.

 

Out of curiosity I actually did a small 10mm thick wooden panel with that engraving tool for a tube-preamp project that over all failed miserably, but the panel itself turned out pretty well, although because the tool is V-shaped one has to take note of the extra force it will encounter the deeper it goes... thus taking quite awhile since I didnt want to strain the machine.

 

as for the speed of the spindle ... The sales listing sayes 7000rpm at 24 volts which is the supplied psu. The motor can be bumped up to 36 volts through the controller, but thats the limit for the electronics.... One could theoretically bypass the controller and run the motor straight with a dedicated psu.

 

Now I have an assortment of shorter dremel routing and engraving bits that are more suitable to this sort of thing, but like I've said I've yet to try them out since I havent had the materials to work with... and more recently motivation issues in general.

 

But I have another chair project that actually needs this machine to get it done (rather intricate oriental pattern), for which I spent about a day wrestling with the G-code plotter for the pattern ... so if I can just get my act together enough it might come up some day.

 

So far I've found GCAM SE to be the best non-cloud/browser based locally installed free to use 2D plotter, the bunny logo in the picture I did with it just by eyeballing the actual one side by side of the programmer.

 

Like you mentioned, I've used notepad to tweak the routes where I can (since it is just 3D space co-ordinate values)... What still eludes me from trying to make programs fully on notepad is the radius commands, which I have yet to figure out how they work exactly... and also knowing that the next command wont cause a collision... since thats not the type of violence I want.. heh.

 

Actually I have to use notepad to process the resulting G-code because while Candle, the visual controller software for the GRBL based stepper motor controller can understand commas (which is the decimal divider here) the GRBL itself will not, and wont move. so commas have to be swapped for dots.

 

To make 2½D stuff one would probably need a full CAD/CAM package like Fusion 360, though this GCAM software does have the ability to make radiuses on Z-axis's too... There is always the pirate option but id rather stay away from that ... since you might get more than you bargained for ... and unfortunately all of Autodesks actual software suites are now subscription based, and Dassault CATIA is just unobtanium for a home user ... but eh...

 

like a pottymouthed canadien youtuber sayes ... You have to work with what you have.

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