UKH

Due to, let's say an accident in an industrial threshing machine, I find myself in possession of very little muscle in my calf. 
It has never caused me much problems, but after forty years of trying to strengthen it by various methods I'm going to build a machine that will, I hope, do the trick. Or at least let me get it as strong as possible. 
 

Just to give you an idea, at the moment I can't even stand on tiptoe,  and to be honest, I don't think I ever could.

So the plan is to build some kind of pedal attached to some weights to provide variable resistance. I only have Limited movement in the ankle,  and can move the ball of my foot four or five cm up and down (compared to 12 ish in the other) so presumably would have to be optimised and balanced well.

I'm thinking a plank to sit on, with a backrest to stop it all shifting, and a pedal ever set up for my foot at the other end. Presumably the length of the lever/pedal doesn't matter  as long as the distance on the other side of the pivot point is the same (the point where the weights - or string attaching them would be attached)?

I've no idea what weight to start with, but let's say I start with 20 kg, and learn to push that consistently, and want to increase, I either add weight, or change the point of attachment. Presumably if the POA is 10 cm from the fulcrum then increasing it to 20 will increase the apparent weight to 40 kg. It's been a while since I've had to think about such things. 

If I can rig up a system that will let me train up to pushing 80 kg then I'll be able to stand unaided on tiptoe on one foot for the first time ever, and a very small handful of routes that I've been unable to climb due to a lack of tiptoe ability will come back into contention (as opposed to the ones I can't climb due to being fat and weak).

Rambling post I realise, but any ideas, or at least confirmation that I'm on the right lines in terms of physics etc would be great 

Ta

GTE

All you need is a staircase. Stand with the forefoot on the edge of a step, and with the help of the banister, do raises. As you get strength use the banister less and put the foot farther out, So first half the foot on the step, then just the ball, then middle of the ball, etc, until you are pretty much on your toes only.

You'll probably be able to do isometrics at each stage before you can raise, so as a stepping stone start raised on your toes/forefoot, let go or relax the grip in the bannister, and try to hold the position or fight the lowering.

Plenty of traversing on vertical walls or slabs also helps a lot, using smaller hand and footholds as you progress.

Tried that, for years and years and years without luck. Well, I'm sure I've improved the strength but not by enough to stand on tiptoe on that foot.

Either there isn't enough muscle mass remaining, there is some factor to do with the lack of movement, or I'm just not very good at controlling the raises /lowers.

Gte

seek professional medical help

To be honest, if that doesn't work then a machine is even more unlikely to do so. For what is worth, it takes a lot of time and a lot of effort. It took me from having effectively zero muscle mass and being not strong enough to even stand on that foot to be able to stand on a bicycle pedal about 2 or 3 months of doing exercises such as the above 4 times a day, 3 reps of 15 at the beginning inceeasing to 5 reps of 20 later on.

Probably took about 5 or 6 months before i could stand on the forefoot, and was already cycling often and climbing in addition to the above exercises.

There really isnt any more specific execise than that, as there's heaps of muscles you have to strengthn and learn to engage as well as working on proprioception if you want to have a chance, and a machine such as you are describing won't help with that.

If you want to analyse the exercise and progress farther, you can use a scale to stand on, that way you know exactly how much assistance you are providing with the banister and know exaclt how much weight you are putting through your foot.

Besides that, a visit to a good sports physio specialising in lower limb post-traumatic recovery is probably your best bet as Scott suggests above. If the problem is of neurological origin then there's other physios also specialising in that.

Good luck

P.s. And on the climbing front, but also as assistance for training, get some supportive climbing shoes. Having loose floppy soft rock shoes would only make your life harder

Do medical professionals often advise on building home made gym equipment? 😉

This wasn't the answer to the question I asked, but is perhaps the answer I needed.

I've had professional medical intervention for the last forty years. I'll let you in on a secret, it wasn't an industrial threshing accident at all, nor even a domestic one. But  scar tissue means I've got naff all muscle, so have learned to cope without.

I've had physio on and off for years, perhaps not specifically for standing on tiptoe though. 

I think I need to revisit the exercises, it's good to hear from someone who's had a similar experience, although probably for very different reasons. The timescales you mention are illuminating, I'm clearly expecting too much too soon so will have to stick at it.

Gte

Join a gym. Mine costs less than 20 quid a month and has specific calf raise machines.

Even if they don’t you can use a normal leg press machine to do calf raises. They’ll show you how when you join.