Friday, 20 September 2013

Trying to guard your trousers

I've had a disappointingly light shedweek, but I have managed to find a little time to make the trouser guard. Our American friends, who aren't as good at sailing as us, call it a pants guard. When I bought my first original penny farthing about a hundred years ago now, I thought this part was a tyre scraper to help prevent headers from stones getting jammed under the head. I was wrong and discovered the truth when I first rode the bike around a bend on a muddy road. As the wheel is steered to one side, the guard prevents your trousers, or leg, from getting abraided on the mucky tyre.

The guard on the original is a full 12 inches long, much longer than on a penny farthing. This is a reflection of the relative safety of the design, the seat being that much farther back and consequently the guard needing to extend farther back to be useful.

The original guard is bent and mangled, it is probably made from the mildest steel.

Due to the extra length of the guard, the material it is made from is important, it needs to resist bending as your leg contacts it. The obvious choice is spring steel, the same material I used for the saddle rails. Here's a tip if you need a small amount of spring steel rod, you probably already know this but you're cleverer than me and I didn't. Model shops sell it in many diameters as piano wire or music wire. It comes in 36" lengths and is cheap and easy to find. The original guard is 3/16" and this gauge is considerably easier to bend than the saddle rails.

First bend two 90 degree bends at the appropriate places.

Then squish in a handy bending jig to produce the rounded end that wraps the tyre. 
Also bend the guard to follow the tyre.

Next grind the rounded end into a pleasing flat profile.

Then the tricky bit, drilling the holes in the fork legs. 
drilling into a convex surface requires a little care to prevent the drill wandering. 
I mounted the fork legs onto the mill table and milled a flat before drilling the hole. 

A little tweaking to get the guard in the right place and at the correct angle.

I still need to heat treat the guard to remove the residual stresses from bending but I need to wait for my lovely wife to go out so I can bake it in the oven at 200 degrees Celsigrade for an hour. I'll then plate it and soft solder it into the forks before I paint them.

She nipped out tonight but caught me when she got back. 
I think I got away with it. I'll let you know next week.

So that's now the frame completed, there is nothing left to do other than stamp the serial number all over the components. Next week I'll start plating some bits and pieces and begin to prep for painting. The weather is rapidly improving here and I should be able to spray the enamel fairly soon. I do like this time of year, we're on the steep part of the seasonal sine wave and the improvements in daylight hours and temperature are rapid and noticeable.

In other news, today is our wedding anniversary, we have been married for ages now. I had hoped to have completed my lovely wife's deck but it was not to be. I'll post a picture when I've got it done, it has turned into something of an ordeal. My lovely wife visited relatives across the ditch in Sydney last weekend and I worked all the daylight hours possible to try and finish it while she was gone. I failed but I did earn considerable family credits for trying. She says I'm often quite trying, now I think about it.


  1. Apparently the Americans are as good at sailing as you, if someone tells them what to do. Having said that they appear not to be able to work a system of government.

    1. I think I jinxed the team when I wrote that, we were leading 8-1 at the time. Having said that, the Oracle crew were mostly kiwis anyway so we sort of won either way. I agree about the government thing, how odd is that situation?