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Picture of Making wooden sandals (Scholl's style)
I like wearing Dr. Scholl's wooden sandals, but I can't find them (men's) in the shops anymore. So I decided to try making a pair by copying the shape of the original. The distinctive feature of this style of sandal is the ridge or or bump that fits between the ball of the foot and toes, preventing slipping. The back is also carved out which stops the heel sliding sideways. The strap is well forward, allowing the foot to rise naturally on the toes when walking. Pressing down with the toes to "retrieve" the sandal while stepping forward produces a distinctive "clop, clop" sound.
I believe Dr. Scholl designed the original sandal carefully, based on a study of the natural barefoot gait.
Later versions, especially in women's styles, diverged somewhat from this ideal.

This shows the finished sandals (a bit dirty; I've been wearing them in the yard).

Total cost: about $25 ($5 for the wood, $20 for a commercial sole). Using an old car tire for the sole might work - I tried, but had trouble cutting the steel belting.
 
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Step 1: The original sandals

Picture of The original sandals
I have several pairs of the original sandals, in slightly different styles as the manufacturer changed them over the years. There are 3 basic problems that develop:: the straps wear out, the woot splits along the grain, and the wood wears rapidly if the rubber sole wears through and I don't get them re-soled promptly. The upper surface also wears down gradually, so the wood can get quite thin at the toes and break. That's what happened to this pair.

Step 2: Preparation

Picture of Preparation
I'm not sure what kind of wood the originals were made from. I picked a piece of oak nominally 1 inch thick, wide enough to cut out two sandals side-by-side (one inverted). OK, it's what they had in the store. The original sandal is thicker in a couple of places, so I glued some offcuts to the top side to build up the thickness in that area.

Step 3: Rough cut out

Picture of Rough cut out
There is a registration problem between the routing and the outline, so for the second pair I made I decided to do a rough cutout first, then machine the surface of the sandal, then do a final cut around the outline. Here I am about to cut the two rough outlines from the blank. Note that one of the blanks is inverted (the upper side of the two sandals are on opposite sides of the wood blank).

Step 4: Gluing riser

Picture of Gluing riser
This is the extra piece forming the instep, glued and clamped. I used two-part marine quality wood glue.

Step 5: Router Jig

Picture of Router Jig
The basic idea is to copy the shape from the original sandal to the wooden blank. The best solution is probably a computer-controlled milling machine - convert a file from AutoCAD and press go. Failing that, a manual milling machine. I believe one can be had for about $600, but the table looks too small. Of course, one can do it the old-fashioned way - by eye, with a mallet and set of chisels.

Originally, I had intended to make a pantograph , using an electric drill with a rotary rasp, that would allow free movement in three dimensions. But it seemed simpler to adapt a drill press, and make a jig to move the workpiece sideways. This allows movement in two dimensions. The 3D shape is built up in slices, like an analog TV picture. The blank and pattern are screwed to the jig from underneath. This leaves a couple of screw holes in the sandal, but they are covered by the rubber sole.

The drill press is actually an adapter to take an electric drill. It's not very good quality, and I had no qualms about drilling holes in it. I mounted a horizontal bar on the press traveller, and mounted a vertical probe in it, parallel to the drill bit.. When the drill lever is lowered, the probe moves in concert with the drill bit. The thing is not very rigid; you have to stop lowering when you see the probe touch the pattern, not when you feel resistance. The probe certainly won't act as a stop.

For horizontal movement, the wood blank and pattern (old sandal) are mounted on a wooden jig. The horizontal spacing of the blank and pattern matches the spacing of the drill bit and probe. There is a wooden rail clamped to the table to which the press is secured, and spacers fitted to hold the jig level. Thus it is possible to slide the jig horizontally in a straight line by holding it against the rail. The drill bit will trace a line across the blank, while the probe tracks the same path across the pattern.
To carve a parallel track, the rail is unclamped and moved towards the drill. The position of the probe is checked to make sure it traces the same line. The drill press allows the drill to be swung from side to side when a nut is loosened; with this setup, the probe rotates with the drill and moves horizontally. Given the geometry of the clamps and table, it is easier to swing the left end of the rail to move the drill across the workpiece (in reality, move the workpiece across the drill), and to swing the drill to move the probe across the pattern.

The drill is set up with a hemispherical router bit about 1cm diameter. When this is used as a router, sliding the workpiece while keeping the drill depth the same, it will carve a semi-cylindrical slot.
In practice, since the press is not particularly well-made and the jig has only limited constraints on uncontrolled movement, it is easier and safer to use the press as a press - drill a hole, raise the drill, slide the work sideways, then drill another hole


The video shows the steps of lining up the probe and router bit so that they track properly.

Step 6: First cuts with the router



This shows the initial removal of material using the router bit as a drill. There is a vacuum hose set up behind the drill; there is quite a lot of material to remove and it has to end up somewhere.

Another approach would be to use a drill, not a router bit, and make a series of drill holes using the probe to control the depth. That would leave a rectangular blank covered with a grid of small holes. Then use some other method to remove excess wood, such as a hammer and chisel or grinder, stopping when the pilot holes are no longer visible.

SAFETY: Wear eye protection (got my reading glasses); wear ear protection (I did with the grinder,; it's noisy); tie back hair (didn't do that); have a kill switch (yes, but not positioned to be usable); keep hands away from tool (oops!); wear a dust mask and/or control dust (forgot the mask, did have a vacuum); keep workplace tidy (you're kidding, right?)

Step 7: Halfway routed

Picture of Halfway routed
This shows the blank with about half the work complete. I started in the middle, the worked progressively across to the right edge. The light area is the extra wood glued on for the instep.



WARNING - this operation is potentially unsafe. I cut my finger on the router when it caught on the work and pulled the entire jig - work, patter, and my hand - to the left. It can also cut into the work where it is supposed to be higher. The risk can be minimised by 1) making more, smaller cuts 2) moving the work against the direction of blade rotation, not with it. That way if the blade catches it will push the work out away from the blade rather than pulling it in. The problem is that, having made the first slot, you are working on only one side of the blade so there is an unbalanced force. Re-engineering the jig and rail so that the work is mechanically held against the rail would help, as would turning the whole thing into a milling machine by adding a screw drive.

Step 8: Routing complete

Picture of Routing complete
This shows the blank with all the routing complete

Step 9: Final cut around outline

Picture of Final cut around outline
This shows the half-finished sandal after the excess wood is trimmed with a jigsaw. Next, the sides are smoothed out with a sander.


Step 10: Sanding the upper surface

Picture of Sanding the upper surface
The upper side of the sandal is sanded with a high-speed disk, removing the ridges between the tracks cut by the router and generally smoothing things out. The high-speed grinder is quite hard to control, so it is important not to allow it to remove too much material. Following the initial sanding, I repeated with a slower-speed disk (disk mounted in a variable-speed electric drill), and finished by hand with a medium-grit sandpaper.



There is a vacuum set up to one side of the work, with a large funnel to try and catch the dust. It was only partly successful. This sander makes a lot of very fine dust that gets on everything. It would be better to do this outdoors, or in some kind of booth where the dust can be better controlled.

Step 11: Planing the sole

The sole of the original sandal is not completely flat; there is a slight bevel to the heel and toe. This gives a more gentle rocking motion when walking and I believe reduced wear on the sole. I copied this bevel by planing the heel and toe of the sandal before fitting the sole. A hand plane raises less dust than a sander.


Step 12: Fitting the sole

Picture of Fitting the sole
The sole is glued into place. I used a commercial readymade rubber sole bought from a shoe repair shop. It is glued to the underside of the sandal with contact cement after roughening the surface of the rubber to remove the shine.

Step 13: Fitting the strap

Picture of Fitting the strap
For a strap, I used a piece of an old leather belt. Instead of using a buckle to adjust the strap length like a store-bought sandal, I just cut the strap to fit my foot. The strap is held in place by wood screws on each side, as on the original. The straps are tilted slightly forward to accommodate the arch of the foot.. On one, the strap was initially tilted too far and wore a hole in the top of my toe, so I had to reposition it slightly.

That's it, the sandals are finished. I put a bit of sealant stain on the edges; I think if the wood gets wet it contributes to cracking. I should probably sand the top surfaces again and treat it with wood oil; the green colour is grass stain - I was wearing them in long grass.

Step 14: Cross-sections

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Some cross-sections of the original sandal (men's size 11 left foot)

You can see the original image by clicking the thumbnail, then clicking the [i] icon (top left), then clicking "original image".

These traces were made using the tool shown in the photo. I'm not sure what it's called. This step is not required to make the sandals using the method described earlier, but might be one approach to generating a data file for a milling machine.
ironsmiter6 years ago
Nice writeup and a cool concept... but GET THEE A CURVED DRAWKNIFE!!!
so commandeth the woodworking gods, and trees alike!

A good Convex Spokeshave would also do wonders(and probably be cheaper). Either of these, with a little practice, should shave 90% of of the time it takes you to contour the wooden sole.

How are they to walk on? I foresee some cushioning issues, when used on modern concrete walks. Indoors, on carpet, or outdoors on lawn, probably fine...
adaviel (author)  ironsmiter6 years ago
Sure, the original English or Dutch clogs were made by hand. But neither of the tools you mention would create the Scholl's shape - not enough curvature. I dare say a curved gouge of the right shape would work.

Personally, I find them very comfortable, Which of course is why I made these copies. I tried a Yorkshire clog one time but did not like it. I don't care to walk a long distance (more than a few miles) per day, or I get a blister from the strap (at least, with the commercial ones - haven't had the home-made ones long enough), and I can't run that well in them. I can, however, climb ladders, go rock-hopping, climb fairly steep slopes etc.

[http://chrisbrady.itgo.com/clogmaker/clogmaker1.htm ]
Ahh, so the curves are deeper than they appear in the finished product images. The shoe I really have always wanted was the Birkenstock sandal (cork sole, rubber tread, leather upper). Sadly, their widest size is a "regular"(D-EE) And, even with a EEE, I have to buy shoes at least a whole size too large. Bad mojo in an open toe sandal. My own mother used to say we'd have better luck fitting the shoeBOX to my feet, than the shoes themselves. Moccasins only get me so far, and they wear quite quickly... and clown-shoes don't exactly inspire comfort. Since I can't even FIND the men's "exercise sandal" section on the Dr's website, I suppose I'll fire up the printer, spit out a few of your images, grab my hook knife, and see what i come up with. Nice soft pine 2x4 should be good for a prototype, then on to walnut burl or oak, for a finished product. I hope. maybe. Thanks for your 'ible and replies!
I don't know if you are going to see this, but I found this site about moccasins and DIY sandals, and thought that it might interest you.
thanks.
Yes, I HAVE seen THAT site before(and a few others).

I have even made 3-4 pair.

they are just never very comfortable.

I did make one pair that was comfortable to stand in, and used them for a while as cooking shoes.
I used a section of semi re-tread that i found on the side of the road.
The rubber just wasn't flexible enough for comfortable long-distance walking though.
Semi tires? YIKES! No wonder they weren't comfortable; they are very hard, as they need to last a long time, supporting heavy loads. Drop by your local race track or tire store and score some worn out soft racing tires.
problem i ran into with other tires I've tried is...
They're still not flexible enough, and have too sharp of a curve to them.
Trying to walk on them is like walking in those "tone your butt and legs" shoes from sketchers. Just horrid.


The semi-tread had the advantage of laying flat.
that's why I tried it.(that and it was free).
Scholl Pescura sandals were available in the UK in men's sizes up to UK12 (Euro 46) until recently. They are not very accurately sized, however; the 46 is barely a UK11. Scholl was selling them discounted to £10 before Christmas 2008. They do now seem to have disappeared from the website. But I have seen them at two branches of TK Maxx and last week bought a black pair in size 46 reduced to just £7.00! If in the UK, it might be worth searching at local branches of TK Maxx.

The Birkenstock Madrid is a generously-sized alternative (45 = true UK11 and quite wide) and very comfortable. Available in UK in black up to 46 from Amazon (about £30); they were cheaper when on special offer last winter!

I wish the original Berkemann B100 was still made and available in the UK; the current models are apparently not so good and are very expensive (about £50).
adaviel (author)  ironsmiter6 years ago
adaviel (author)  ironsmiter6 years ago
I made some crude measurements before I came up with the copying jig. I also made some fibreglass moulds thinking to iterate (carve,check).
I think these are centimetres. If I can believe my list, the heel depression is nearly a centimetre deep. The distinctive Scholl thing is a bump between the ball of the foot and the toes; that's what lets you climb uphill without your feet slipping out, and lets your foot naturally rise up on the toes as if you were barefoot. I think the original Dr Scholls were carefully designed from anatomic principles; the women's designs seem to have diverged somewhat from this principle (high heels, for one thing).
http://andrew.triumf.ca/andrew/sandal3.dat (plot with "gnuplot splot")
http://andrew.triumf.ca/andrew/sandal3.png

If you are interested I can try and make some traces off the original shoes - I have a metal tracing tool I bought to trace a boomerang wing but never used.
I may do it anyway.
Goedjn adaviel4 years ago
There are different kinds of curved drawknives. You want the kind that's designed for barrel-staves, and/or chair seats.
richie_1143 years ago
I've been using an old leaf blower as a dust collector, Well..... It shoots the dust out the window of my shop into the woods by my house.... makes good mulch as long as I don't let walnut dust go out there too.
richie_1143 years ago
Way too cool! You essentially took a pantograph and made it simpler!
Finally! something to do with that "portable drill press" (same as yours I'm sure)
I was about to toss it in the trash since it only works well if I bolt it to the piece I'm drilling.
This could be along the lines of what I've been thinking of doing - carving some soles for a pair of boots I'm planning to make. When I have the time, and the opportunity to acquire some tools, I'll see how far this will take me towards my target.

Thanks muchly in the meantime!
unjust4 years ago
lovely! the tool you've built is known as a duplicating machine in several industries. they were used before CNC for limited run rapid prototyping (and even some production work, you could get 6 or more routers going off of one template). you build a master, and then you duplicate that first starting with a larger router bit to rough out the shape, and then going over that with a finer bit to eliminate surface notching. it's important to match the probe to the bit you're using.

wooden type was often copied in this manner.
Rubber sole - bike tire.road tire Strap can be made using the innertube - completely recycled.
do a search here on instructables for " 3 axis dremel pantograph " , It looks like just what you need for this project !!
hey in my country (Indonesia) its called "BAKIAK" sandals. its a traditional sandals from Indonesia.everyone will hear you while u walking.haha...
Pretty cool. I don't have any of the wood working tools that you do. Maybe I could make a form-fitting wooden sole by building up veneer into plywood on a foot-shaped form. I'm thinking that you could make a cast of your footprint in sand or plaster then make a form from resin or plaster and make the plywood off of that.
adaviel (author)  discontinuuity6 years ago
I thought about that for my second pair, but forgot to do it. I was going to stand in some silly putty or "blu-tack" covered with Saran wrap, then measure from my heel to the front of the ball of my foot, i.e. where the ridge is on the sandal, and adjust the copy as necessary. I'm not sure messing around with laminating veneers would really be any easier. What this really needs is a milling machine. Failing that, probably a "roughing gouge" and mallet. You need some way to carve a concave surface, so a regular flat chisel or knife would not work.
Mtalus6 years ago
As a woodworker with size 10, 6E feet I've also made my own; that was before the internet and the ease of online orders in my size made me lazy. I wish I could remember just how I jigged a pantagraph router setup to copy a cast of my foot (a simplified contour plaster cast). I made the uppers from leather, boot profile, and the rubber on the sole was old conveyer belt. They were great and insulated my feet from a cold floor. Later I met a man from the UK and they really brought back memories for him. Ironically I had never heard of alder soled dairy clogs but that's what I had made (according to him, still awaiting confirmation). He then gave some info that improved them: A band of brass set perpendicular to the sole around the heel and toe, depending on where your sole wears most, will really help them last. It would scar up a floor I'm sure but that wasn't a problem in the barn or shop.
:D I was just thinking last night that I should make some sandals with wooden soles. Freaky! 5 *s and faved. :)
for soles another non-scuffing option is to go traditional using thick leather and small tacks to secure it
awoodcarver6 years ago
Nice work , I do remember these and wearing them out over the years
bustedit6 years ago
nice job. we called these "clogs" when i was younger. my friend, Red, got kicked in the cohones by a girl @ recess with a pair of these on, yikes.
jolshefsky6 years ago
A friend of mine taught me a "trick" of coping using an angle grinder for metal (and, preferably, with a sanding disc installed). It seems that might be useful in making these, although the pantograph-mill device is pretty cool.
ve2vfd6 years ago
Holy cow! I haven't seen those sandals since the early 70's when everyone used to wear them! What a trip down memory lane. Excellent instructable, super clear and detailed!
Wow! Excellent work, very clever routing routine! Thanks for sharing! K.