The Pedal Files

What the pedals look like. "Great for someone who likes driving in clown shoes"

I realised I hadn't done a post showing the actual finished pedals. As I am writing this blog somewhat retrospectively, (it takes a lot of time to make the things and blog about it) this post is a little out of date but is what-I-done-wrote at the time: 

As I detailed in my 'more holes than...' post. A lot of drilling work has been done to the pedal units. Since then I have been able to finish off the pedal units – although I'm sure they will need a lot of alteration and adjustment.

Firstly I cut a length of M8 studding to around 200mm length. This is passed through the hole in the main support piece. From the photo it can be seen (if you squint) that the threaded rod is free to be pushed further into the pedal box, the only thing stopping it is the spring which acts on the top large diameter washer which itself is secured by a nut. At the other end, the large M8 eye nut stops the rod being pulled out of the pedal box by the spring. A length of steel cable will be attached to the eye bolt, run over the pulley and then attach to the pedal arm. When the pedal is pressed the eye bolt is pulled further down into the pedal box. Somewhere along the length of rod inside the spring is a stop-nut. This will stop the rod being pulled further.

Rear view showing the 'Spring Assembly'. The upper washer is attached with an upper and lower bolt. The 'stop nut' is two M8 nuts locked together.

The next photo shows the finished pedal – this time it is the brake pedal. The wire rope is attached to the eye bolt and this runs over the pulley attached to the rear support piece. The pulleys fit a ¼” steel shaft, although this appears bigger here because I have used two pieces of aluminium tube to space the pulleys and keep them in the middle of the shaft. As this is the brake, the mechanism is a little more complex: the 'spring assembly' passes through the 'L' bracket for the load-cell. This 'L' bracket is pivoted through the main support piece – which is mounted vertically on the brake as opposed to horizontally on the accelerator. 

Rear View of the Brake 'Pedal Box'

 

Close up rear view of the Accelerator 'Pedal Box' - now attached to the wooden base (partly by vertical bolts seen nearest camera). The black thing around the wire rope is an ordinary cable tie (trimmed after fitting) - this helps keep the wire rope in position during fitting. The wire is not quite as flexible as I'd ideally like and tends to want to spring out from the pulleys. Once assembly is complete however and there is a bit of tension in the wire, this is no longer a problem.

I use some more of the 'plain bearings' to try to smooth the movement of the M8 threaded rod through the main support pieces.

I had a few problems here with the wire rope. Firstly it is not quite flexible enough for what I am trying to do here. This makes it difficult to get things threaded up neatly. Secondly the fastening to the pedal arm isn't quite as I originally intended; The M6 eye bolts which you can see attached to the pedal arm are difficult to fit as I do not possess any M6 nut tightening device that will fit inside the pedal arm to tighten the nut (M6 nuts need a 10mm spanner). Through a bit of improv I manage to get them fastened ok and they seem to have held so far. The other problem was the size of the 'wire rope grips' which fasten the two ends together. My original plan was take the wire rope coming from the pedal box, loop it through the M6 eye bolt, back over itself and fasten it inside the main pedal box with the wire rope grips. This wouldn't work very well because I hadn't left enough clearence between the wire rope and bottom of the pedal box. You can see the alternative solution that I came up with in the photograph.

"Improv" wire rope fitting to pedal arm. The two ends of the wire rope are secured with 'duplex wire rope grips' So far this fitting arrangement has been 100% secure.

At first when I was trying to tighten up the wire rope I thought the inflexibility of it may leave too much slack in the system. With a bit of trial and error though, I am reasonable pleased with how it has turned out. I found the best way to get a good bit of tension in the wire rope was to loop it through the eye nut on the spring assembly. Have the spring assembly in place held with a stop nut on the other side (no need to have the spring there yet). Then use trial and error to find the best position to apply the wire rope grip. To finally fit things I have the pedal arm nut into the wire rope, then lever it into position using the front support piece as the fulcrum, then I pass the pedal arm axle through to lock it position.

So, at the moment I think my pedals look like great for someone who likes to drive in clown shoes. Obviously they will need some kind of foot rest box if they are to be used as they are now. I had intended to build pedals in 'hanging down' configuration but changed my mind part way through. I think they will still be good but they definitely can't be used 'as is' without something to raise the height of the feet. After I took the main photos, I took the pedals apart again and made some adjustments. The pedals are now mounted a little lower down on the pedal arm and I have rejigged the spring assembly – the 'stop-nut' now consists of two nuts which I can lock together into position. I also filed some grooves in the bottom of the pedal arm. The wire rope passes through these and is kept nicely in position.

Groovy

+Additional

Since making further adjustments I have changed the rest position of the pedals by repositioning the front support/pedal stop pieces. I also drilled two holes in the lower face of the pedal stop  - these are so I can add bolts to help set the rest position of the pedal. Repositioning the front support piece by drilling new holes in the side pieces of the pedal box is massively time consuming, so these new holes make the process of adjusting the rest position of the pedal relatively quick'n'easy. I wanted to adjust the rest position because I felt the pedals were too 'upright' during test drives.

Front view of the accelerator 'pedal box' with 'pedal arm' removed. Note the two holes in the lower face of the 'pedal stop/front support piece' Bolts can be placed through these holes to 'angle' the rest position of the pedal more. Further angle adjustment is possible by adding/taking away washers from such bolts. Note also the front brackets which secure the 'pedal box' to the wooden base.

 As can be seen. I have now brought some wood with which to construct a wheel stand. This will be the subject of my next post.