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View Full Version : My latest TAD project



Michael G
21st Aug 2017, 07:16 PM
As some know I do volunteer work for TAD. Sometimes these projects are relatively simple, but this one has been hanging around for a while and has had a few wrinkles, so may be worth mentioning.
The client started off not knowing what he really wanted, except that the backrest of his walker was not comfortable enough, so part of the job was to work out what was needed. I made up an adjustable backrest to work out what was needed and having spent some time with him trying various positions, worked out that he wanted something higher and further back than the standard back rest.
Walkers are usually made from 3/4" Al tube, so the next thing was to bend up some tube, which required making up a tube bender.

This is copied from one that I saw a year or so ago for bending small hydraulic lines. Excuse the workmanship but I made it mainly as a one off device (although I will keep it as it is bound to come in handy). First photo is the base part. The block to the left is to clamp the tube so that it has to bend around the former - made with some PE that Kryn gave me a while back. The underside (second photo) just shows the hex spigot. This is held in a vice and being hex, the base can be rotated around for better positioning. 3/4" tube is a bit stiff, so I ended up sliding the mill vice to the end of the table and using that - no piece of Al tube is going to move that vice...
The bar to bend it is just some flat with a piece of tube welded on for a handle. The 32x5 bent a bit so it could do with being stiffer. The roller is PE again, and runs on a sleeve the same size as the main spigot - this is doing R50 bends but in theory I could swap the wheels and do R25. The profile on the two wheels was done with a 19mm router cutter in the mill with the wheel blanks on a R/T.
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The clamp block fit was obtained by sandwiching a piece of card between the halves before drilling (a rough bore is preferable for holding the tube).
All in all the result was quite good. There was some flattening of the tube across the outside of the bends but nothing disasterish
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With a back that high though the lever arm on the plastic brackets that the backrest slots into was increased, so those brackets were remade in Al. Shown are the brackets drying after a coat of paint.
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To get that offshoot at 45 degrees, the standard way would be to put the part on a R/T, mill one leg, rotate 45 degrees and mill the other. However, as well as feeding in X, Y and Z, my mill has feeds arranged so that I can feed in two directions (X-Y and X-Z). In this case I was feeding in Y and then when I got to a scribed line I additionally fed in X so I got the angle (that is, feeding both X and Y at once). I must admit that these machine capabilities are just a party trick until you use it on a real job, but really nice when you can use them.
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The other interesting one was getting the octagonal profile on the barrel. Normally you would just kick the part over 45 degrees and go for it with an end mill but you will notice a couple of bosses on the side of the part. These are for support where the part is clamped to the frame. To get those I fed along, stopped, moved out then along, back in and continued. The boss was then dressed up. The cutter is a 12mm slot drill that I sharpened up with a chamfer on the corner. By stepping up and across the same amount, I got a 45 degree surface (admittedly that needed a little clean up)
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Hopefully there are a few ideas there that others can use.
Michael

KBs PensNmore
21st Aug 2017, 08:34 PM
Fantastic work Michael, as usual:2tsup:. We get to expect nothing less from you.:D
If I come across a similar problem, I'll know where to come.
Kryn

simonl
23rd Aug 2017, 08:52 AM
Hi Michael,

Once again, a very entertaining project.

BTW, my dear mum uses one of those walkers, as did my Dad when he was with us. While you have provided us here with yet another intereesting read, it no doubt means even more to the recipient of this modified walker.

Is there any better way to make use of your time, skills and tools than to improve the quality of a persons everyday life?

Simon