Introduction: Custom Wooden Crutch
Nothing says, "I care that you make it to the bathroom okay" like a pair of custom made crutches. Especially when they were made out of a single 8' 2"x4" each...*Plus a few odd scraps. **Each crutch was made almost entirely out of a single 8' 2"x4".
It should work out if you plan your cuts right though. When I was done I ended up with a bit extra out of the one 8' 2"x4". This was because I chose to use up some shorter pieces that I had lying around for certain bits. Why? Because how often do you get to do that? But we'll get back to that in a minute...
Regardless of the material efficiency, there is no real reason to make these, other than the fact that...honestly they are pretty cool. Beyond that, there is no adjustability, there is no space saving foldablity options, and there is no compromise! But they did turn out pretty cool though.
I'm sure this begs the question: "why would a person make them then?" I made them for my dad as he inadvertently hurt his knee, unfortunately. Given at the same time, during a winter storm episode in the single digits, the battery in my daily driver decided to give up. I'm certain most of you are aware, as batteries pass, and all of the electrons fall out, it happens at the best possible time in one's schedule. It was looking like the closest possible thing I had to a crutch available was an Amazon Prime order 2 days away. (Not an ad for Amazon, just saying.)
It was at that point I got a rough idea. I also figured I probably had the materials combined with the slow accumulation of some of the tools I personally find necessary for woodworking. So I just decided to make my own crutches. Ironically, working on this project would allow me to take my mind off things for a bit and grieve properly for my recent battery loss. Nothing says, "I don't need to make you crutch but you will be... my crutch... while I make you...." or something like that. Homemade crutches speak volumes.
Step 1: Planning
A plan is hopefully the best first step to every project.
I normally make rough sketches of the projects I make, but most of the time, a lot of the important information is just bouncing around up in my head during the project and I really don't know what certain dimensions are until I get to that step. Once I get there, what to do next becomes apparent. This is not always the best approach, I do what works for me.
If you have the ability to draw better than me or use software for this type of step, I highly recommend it. It will most likely save you a lot of time in the long run. I say most likely because sometimes planning can be a lot of overthinking and fussing over problems that will solve themselves when placed right in front of you. Most likely though, proper planning has a high probability to save you a lot of time.
I mainly just put this in here to illustrate that while I'm admittedly, not the best at planning, I do try to do the minimum. If you notice, the picture I drew is proof of the minimal planning claim...but it only somewhat resembles what I ended up with. I changed some of it on the fly. Deal with it.
Hopefully, if someone was thinking about doing this or wants to try it out after reading this, this Instructable will serve as a good starting point to modify and improve upon. Less, I mean, easier planning for all! On to the making but first, a word from the obligatory disclaimer.
This project and its applicable use is to a previously injured person. If you decide to make this, that means you understand all of the risks and safety concerns of making and using the end product.
Step 2: Source Materials and Machine
This entire project, the way I designed it, works with the same size square stock. *excluding the piece needed for the very top. This extra piece is of a different dimension, I'll refer to as the armpit piece. Any of the dimensions could easily be changed as you see fit, within reason I imagine.
For me, the main dimension ended up being about 1 3/8". This is mainly because I could rip a single 2"x4" in half on the 4" side and then plane it down to size. The armpit piece dimension was 2" X 1 3/8" X 8, so it has the same thickness, but has a bit more height.
If you're like me, then you probably always have a few extra 2"x4" lying around. Probably warped and twisted, as well. The lumber may also happen to have a distorted disposition;D
This type of hard to use 2"x4"s are most likely the best candidates for this project. That is, if you have a planer/jointer, are really skilled with the table saw, or have some other preferred method of milling that works for you. I chose some of the worst ones closest to the top of the pile I had, if you look in the photos, this particular one was kind of going every-which-way. It wasn't terrible but it was pretty bad and also had some splits near one end. More importantly, it was close to the top of the pile.
I finally got a planer! It's a Makita and it works perfect for what I need it to do on this step. I'm planing construction lumber yes, but I'm still new at this woodworking thing so all the practice I can get helps.
After picking my 2"x4" out, I planed it down on the 4" side, alternating sides, until both sides were smooth. I then set up my table saw to rip the piece in half. Once that was done, I returned to the planer, planing both pieces at the same time and all four sides down to what would end up as smooth square enough stock.
As for the armpit piece, I had a "scrap" cutoff almost the exact length I needed. All that was left to do was plane it down to the same thickness as the square stock and rip off the broken edge.
Also, I should mention up front that the majority of this Instructable will be about the first crutch I made in one night. I will have a few photos of the second one, I knocked out the next night starting with Step 11. I did this because it will provide a summary of all the steps up to that point and also a cut list of the exact length of the parts that will build this crutch in case you pretty much get what to do and just want to get to the making.
Step 3: The Armpit Piece
It took some time with a tape measure, some mirror angles, and goofy positions to accurately measure my own armpit from front to back. Granted, I was building this for my dad, but come on, there was no way I was going to ask to measure his armpit. No way.
Keep in mind that if you attempt this project, the whole goal here is to connect your armpit to the ground so your leg doesn't have to anymore. If you're going for custom fit you can make this part as custom or as standard as you please. I was on a one night type of deadline so I chose a more "what's comfortable for me should be comfortable for you" approach. We're approximately the same size/height/build however you want to refer to it, so I figured I'd be okay to assume the same armpit support length.
With the idea that it all starts at the armpit, off I went. I took the rough stock and freehanded what I thought was an aesthetically pleasing curve onto one side of it. The main curve went from the full 2" height down to about 1 5/8" height down in the center by the time it ended up a finished product.
I then marked out where I wanted to have the sides attach and the respective mortises. The mortise locations depend on the thickness of the stock, and how wide I wanted the handle area. I usually allow 4 1/4" for any handle that I make for a comfortable grip and this case was no different. For those of you following along, 4 1/4" + (1 3/8 X 2) = 7 which would be the very outside marks on the armpit piece. The very inside marks would be placed at 4 1/4" and each one is 1/2" thick. These are all with respect to center of course. (Refer to picture 2 of this step) This layout would also allow for an 1/2" overhang on the armpit piece which is kind of what I was going for and why it was cut at 8" length to begin with.
I wanted to try out some mortise and tenon joinery on this project just because I haven't tried it yet and I thought it would be really simple to assemble in the glue up stage. Spoiler alert: Pretty sure this may count as a traditional mortise and tenon fail because they all go full width of the stock, but I'll get back to that in a minute.
Once I had everything marked out, I roughly cut the curve out with my jig saw and promptly set my router up to remove the bulk of the waste for the mortises. I'm using a 1/2" straight cut bit with my edge guide to do this. This was a first for me was using the edge guide. It was a bit tricky to setup but after some fiddling I finally got the hang of it. I just used the layout lines to eyeball the bit into alignment with the slot I wanted to make.
After that was done, I put the armpit piece in some parallel clamps secured to the top of my table saw and went about cutting my mortises. This was all done in 1/4" depth increments with the plunge base. My plunge base has a stair stepped depth stop so, once set up to the initial depth on the top step, you can drop it in 1/4" increments 3 times. This gave me a 3/4" deep mortise 1/2" wide. Unfortunately, I marked out and cut the length of the mortise equal to the entire width of the stock so when put together, you can faintly see the edge of the mortise on either side. Not a deal breaker, and certainly not that important in this case, but guaranteed I won't make that mistake again unintentionally. Embarrassing.
Step 4: The Mid-section
With the armpit section well on it's way and a good idea of the final total height I wanted (around 54") for the crutch, I could begin on the mid section.
I cut two pieces 40" long on my miter saw and set up my table saw to cut the tenons. Technically speaking these weren't what I would call traditional tenons because I didn't have traditional mortises to receive them. They are more like tongues I guess being full width of the stock. Anyway, being that I had 1 3/8" stock and a 1/2" wide mortise, I set my table saw at 7/16" height to attempt a perfect centered tongue on the end. I then set my rip fence as a stop barely less than 3/4" and then nibbled away the material using my miter gauge.
I cut the two tongues and test fit them into the armpit piece and I did pretty good with the fit. They were snug, but not too snug. I was surprised.
Moving on, I cut a piece off the square stock on my miter saw for the handle at 7". With that piece cut, I put the armpit/midsection assembly under my arm and tried to place the handle in relation to the armpit piece where it would be comfortable. Originally, I had measured it to be higher but I decided to double check and I'm glad I did because I don't think it would've been as comfortable. So I set the height at 16.5" down from the bottom of the armpit piece to the top of the handle and marked out where to cut the slots to receive the handle.
Using the same setup on the table saw for the tenons, I cut the slots in both pieces using the same nibbling technique for the handle.
Step 5: The Handle
I wanted to join the handle using the same slot and tongue technique I kind of used earlier.
Looking back on it now, I suppose I could've or rather, should've cut tenons on the handle and mortises into the side of the midsection pieces? I just thought that this way would give more material on the handle versus more material on the uprights which, vertically are very strong that way already.
Having the handle already cut to width, and my router already set up for the center of the stock I was using, all that was necessary was to mark it out and run it through. I cut the same slots in 1/4" depth increments from both sides of the material and on the last step, they met. This makes a pretty easy job out of it. I had a bit of cleanup to do on the cuts because it wasn't perfectly centered for some reason or another that produced a small step. After that, I squared up the the ends of the slots with a 1/2" chisel.
Step 6: The Lower Section
With the armpit section on and the handle fitting, I could move on to the lower section. This was the hardest part for me to figure out because I was attempting a 3 way junction at the bottom. This would prove to be a bit tricky because I didn't have a set angle that I was going for. Ultimately with a set mid section length this angle really dictates the length of each lower section piece. This would also be especially tricky because they all need to come together, ideally seamlessly, and the lower section as a whole would add the length to complete the final crutch height. I would also be doing a sort of angled tongue and slot joint, which would mean more length to each individual piece and even more dimension complications. I'm sure there is a better way to figure this out but this is the way I did it.
I played around with the bevel gauge on the edge of the mid section until I decided on an angle that looked okay, and by okay I mean the best angle that seemed to be strong while simultaneously looking good proportionally. This angle for me would be 30 degrees. With two pieces being joined and my total angle of 30 degrees, this meant that I would need to cut each end at 15 degrees. That way when they are placed together, they add up to a total of 30 degrees tilt and still somewhat "line up along the 1 3/8" dimension". I figured out due to total height restrictions, I needed to cut a little length (about 7/8" ending up at a final length for the mid section piece of about 39 1/8" from tip of tongue to tip of angle) of both of the mid section ends and @ 15 degrees. Going between you're miter saw settings and your bevel gauge can be very confusing. Once again, I'll get back to all that in a minute.
To mock up the angled pieces in the lower section I started with a longer piece than I needed and cut one end at 15 degrees. At this point I decided that I would cut the slots into the mid section angled end and the tongue on the mock piece just to rule out the joint as a length variable. I did the tongue on the table saw using the method of nibbling I did in the earlier steps with similar setup only with the miter gauge set to the correct angle. The slot I cut with the router very carefully using the same setup and small increments just as before. Both were 3/4" depths and 1/2" widths.
With that out of the way I slid the angled piece in the slot of the mid section piece and clamped it in place. Now I could use both a combo square to find perfect center of the assembly, and place my bevel gauge set to the correct angle on that center mark (3.5"). This allowed me to mark a line down the bevel gauge of where to cut the angled piece in order for it to meet the other side in the exact center of the crutch or, at least in theory.
Marking it this way would also give me my angle of which to cut at to provide proper alignment for the stilt. According to the bevel gauge, this was 30 degrees. According to my miter saw, this was more like 60 degrees. So remember, there are three angles in a right triangle. One of them is 90 degrees, that's a given, but depending on which side of the stock you're measuring from, your bevel gauge could confuse you. Or at the very least, me. It helps to have a concrete pencil line to refer to at these times.
After the confusion subsided, I made my cut at 60 degrees and made another piece just like it. Once that was done, I knocked out the rest of the tongues on the table saw with my miter gauge set parallel to the cut angles and using the nibbling technique. Nibbling the 60 degree angle was a pretty sketchy angle to be cutting like that with the miter gauge, so I used a push stick to support the piece and keep my hands as far away from the blade as possible.
Step 7: The Stilt
A couple of hours later, I had all the angles figured out and a total length of the lower section up to the point of the the angles. This provided me with a datum of which I could finally cut the stilt.
I cut a piece of stock for the stilt at 12" on the miter saw. After that, I cut the very points off of the tongues so that they would be inline with ends of the full width section of the angle pieces. This would allow the slot of the stilt to fully seat to the bottom of its slot and to help conceal the tongues within said slot.
I actually cut the tips off wrong. They should've been cut at the opposite angle for the stilt to end up seating fully (refer to the first picture in this step). Being that they were inside the joint, I didn't worry about it. I will go on to fix this in the next crutch.
Once the stilt was cut to length, I cut the slot on the router and squared up the slot with a chisel just like with the rest of the slots.
Step 8: The Edges
At this point everything fit together pretty good and it came out to be the right length. Some of the joints were a bit gappy and it really wasn't proper mortise and tenon but it resembled a crutch.
In order to make it usable, I decided to hit all the edges with a 3/8" roundover bit. On the stilt, I ran a 45 degree chamfer bit. Not much to say about this step. The bits have bearing guides on them and pretty much do the work for you, just be mindful of direction of travel and what edges need and don't need cleanup. I decided to do all of this pre glue up except for the joint areas because I thought it would be a bit easier. I skipped all the joint areas so that I could run them after final assembly so that it would feather those areas more effectively.
A final dry fit and I was ready for glue up.
Step 9: Glue Up and Screws
With all the pieces fitting somewhat okay, it was time to wrap this up whether it was perfect or not. When the night was over, I was walking out of the shop with one crutch, no matter what it looked like.
As with any glue up, its basically a matter of spreading the glue and fitting the parts. It helps to be prepared with your clamp strategy so that the glue isn't half dried by the time you get pressure on it. My joints were a bit gappy due to a little bit of confusion on the measurements/angle debacle, so I opted for c-clamps to get some good pressure if I needed it.
In pursuit of wrapping this up, I waited maybe 30 min in a 60 F degree environment and then removed the clamps. The glue seemed to be solid but, I needed to do some finish work on the edge roundovers and general cleanup/sanding. I went ahead and predrilled/countersunk 1 hole in each armpit piece connection, 2 holes in each normal joint, and 4 down in the stilt to accept 1 1/4" #8 screws for maximum strength. I think under normal build time conditions and with some work on joint choices/tolerances...maybe even with a hardwood choice instead of construction lumber, one could totally get away with no fasteners for a cleaner look. I honestly don't mind the look of screws, especially the torx drive ones. After receiving the crutch my dad commented that, "it gives it that aircraft rivet look" to which I retorted, "are you patronizing me bro?" We had a good laugh.
I finished up the roundover work in the corners of the handle area and such. I also trimmed the corner that sticks out where the lower section meets the mid section. I will put some comments on the pictures in this step to point some things out if this is at all confusing.
Step 10: Finishing Crutch 1
I did a quick sand with the random orbital sander with just 80 grit to smooth out all the router marks and to flush up some of my joint discrepancies.
I then put a coat of paste wax on it because I wanted it to have some sort of protection in the winter moisture but I needed to give it to my dad to use as soon as possible.
The next night I would finish up the second crutch with all the knowledge of this one and it would go a lot faster. The next steps will show how that one went.
Step 11: Pieces and Cut List
My dad liked the first crutch and it instantly helped him get around better. He thought he could do better with another one and I agreed, adding that while I was making these, it'd be super easy to knock out another. This would make a matching pair. The rest of these steps assume you already have enough stock ripped and planed to size.
My first step was to do some playing around with my bevel gauge to get down what angle is what according to what the miter saw read on it's scale. I labeled the lines according to what the gauge read when I marked the line and then chucked the piece in the miter saw to see what lined up. Notice that the line says 30 and if i were to set the saw to 30 it would be ridiculously wrong. Two different sides of the same angle. Same for the 75 and 15 degree marks.
My miter saw only adjusts to 50 degrees max so I set the saw at 45 degrees and placed a back spacer to make up the extra 15 degrees to 60. I also thought ahead on this cut and was able to use each side of the cut for two pieces of the one tricky 60 degree cut. With each 60 degree angle cut I could then cut the 15 degree angles on the opposite ends. Those are the hardest pieces to cut and need to be accurate to line up right.
Here is the cut list for my crutch which has a total height of 53 3/4" right down the center (from the dip in the armpit piece to the very end of the stilt) and these are the parts for one crutch. All cuts are 90 degrees unless specified. All stock is 1 3/8" square stock, except for an 8" section of 2" X 1 3/8" for the armpit piece. Its a good idea to pay attention to grain orientation throughout the project to take advantage of the natural strength.
-Hard angled pieces for lower section(measured from outside longest tip of angle to longest tip of angle) - - (2) 7 3/4" - - 60 degree angle on one end 15 degree angle on the other, both angles inward toward each other (refer to pictures)
-Handle - - (1) 7"
-Stilt - - (1) 12"
-Mid section(measured from outside to longest tip of angle) - - (2) 39 1/8" 15 degree angle on one end
-Armpit piece (different stock 2" X 1 3/8")- - (1) 8"
Being able to just cut these pieces out in a batch saved soooo much time and I was actually more accurate than the first one.
Step 12: Marking and Setup
I set up my table saw for cutting the tongues and I actually used a test piece to double check that the resultant cut was going to be what I wanted. Once I had the height I wanted (a little less than 7/16" to make a tighter joint yet) I locked the height down with a cleverly placed bungee cord just to make sure it didn't move.
I then proceeded to mark out all the cuts I need to make in one step based off of the measurements from the first one. This made me more accurate just due to the fact that I was marking them off one by one and not in different lighting and growing increasingly tired...etc.
Layout list according to the way I was making the joints:
Armpit piece - (2 slots on bottom)
- 1/2" wide X 3/4" deep X 1 3/8" long and
- arranged with the inside of the cuts 4 1/4" apart and the outside of the cuts 7 inches apart with respect to being centered. I say it this way because maybe you don't have exactly an 8" piece cut...measure from centers.
Mid section piece (each piece) -
- 1/2" thick, 3/4" long tongue on one end,
- (1 middle-of-the-piece tongue) 1 3/8" wide either side to create 1/2" piece in the middle @ 16.5" down from top (measured from bottom of armpit piece to top of handle slot),
- 1/2" deep slot parallel to the 15 degree end and centered 1/2" wide and 3/4" deep.
Lower section piece -
- 1/2" thick, 3/4" long tongues on either end parallel to each angle.
- 1/2" slot completely through the stock and centered, 3" long from the end you designate as the end that will connect into the 3 way joint.
Feel free to modify.
Step 13: "Mortise and Tenons"
I knocked all of these out in batch fashion. It's pretty satisfying to just stand at a table saw and know what you're doing. In this way I was able to go through the cuts without the need to design as I went.
I did all of the table saw work first, then did all of the router work second cutting all the slots. You could do both on the table saw but I already had the router set up from the night before and it did a fairly accurate job without much effort, so I stuck with it.
Step 14: Fine Tuning and Fitment
With all the pieces roughed out, I had to fine tune them a bit. Chiseling all the rounded ends of the router slots square and some fitment issues here and there.
I also cut this set of lower section points off correctly this time so that the result is a square area where the stilt seats in the bottom of the slot. I also found out that if I trimmed about a 1/16" off the inside of where the angled lower section pieces fit together in the slot of the stilt, that it made all of my joints in the lower section fit together just perfect. I got a lot less gappy fit this time. I can only accredit this to batch work and paying attention to where I made mistakes on the first one. Tighter thickness tolerances in the joints and more accurate angle cuts are just some of those things. It is still not perfect, but if you compare the two, there is a definite improvement.
Step 15: Glue Up
Glue up is pretty straightforward again. Spread the glue, clamp, make sure everything is square and aligned, and wait it out.
Step 16: Final Touch Up and Finish
I chose to assemble this one and glue it up first and then go after it as a whole instead of each piece with the edge roundover. It all worked out about the same time wise with the only drawback being that I couldn't approach the armpit piece without rounding over the outside underneath edge of the armpit piece. I liked the bottom edge of the armpit piece remaining square so I just fine tuned these small corners on the mid section pieces with a chisel to match the rest of the roundover and started sanding.
After sanding, I was in a bit of amazement at how these previously warped 2"x4" 's got machined down and assembled into something that actually turned out pretty straight. This was the third picture in this step.
I then pre drilled, countersunk, and put screws in all of the joints. Again, just for extra strength. That, and I'll admit I'm kind of obsessive when it comes to things needing to be symmetrical. Even if this crutch had perfectly fitting joints, which it doesn't, the other crutch had screws. So now this one does too. This crutch then got the same sanding and paste wax for finish.
After completion, I was able to put my full weight (190 lbs) and balance on it and I never heard or felt anything other than solid. No squeaks, no cracks, or complaints whatsoever. I felt confident that as a single crutch and definitely as a pair, these would be able to take whatever abuse the average person could throw at them under normal crutching conditions.
Step 17: Final Pictures of the Pair Together
Here are some final pictures and some parting thoughts. I think these could be pretty epic if done in hardwood.
I know that there is room for improvement. I think weakest section of this whole design is the lower section. This angled section works a little better than I thought it would, even if the fitment is a bit sketchy. When weight is applied, I can imagine the force pushing down against the 15 degree angled cuts which in turn pushes in tighter towards each other at the 60 degree cuts where they meet the stilt in the center. All of the joints are what I believe are called a long grain to long grain glue joint which are pretty strong and on top of that, reinforced with screws. It creates one of those, "it has to catastrophically fail" situations where a lot of things would have to break at once in order to fail completely.
I would've liked to get rid of that gap on the backside of the joint where the lower section meets the mid section but again, I have a problem with symmetry and didn't want to change the design within this pair. I think the only way to accomplish that would be a proper angled mortise and tenon which is obviously way over my skill level at this point. I suppose you could dowel it or something similar.
As far as the rest of the project, I'm pretty happy with how they look and turned out. I ended up with something functional and that actually got used immediately, with little to no regard for my craftsmanship. I learned a lot out of this project and the more I struggle at woodworking, the less frustrating it gets.
Luckily my dad's knee got better shortly after this and the injury wasn't serious but it's always nice to have something that works in a pinch when you need it. I hope that this helps or inspires you in one way or another. At the very least, I hope you enjoyed reading along. Thanks for checking it out!
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