The Mad Squasher Strikes Again.......

[Fitzroy]

I just did a tool tryout on a male press die for pressing O gauge tinplate coach bodies (1937 Victorian Railways Spirit of Progress stock). Just a temporary setup, Male die only with a piece of brass sheet as a female die/intensifier. My technique is to spark erode a male die, get it heat treated, then if I have or can find a press with sufficient tonnage, press into some ground mild steel plate to create a female coining die.

This time around, the people who made the male die and who normally pony up a 500 ton press to do the necessary have had a breakdown, and because I am just about their only customer for using the 500 ton press these days, haven't fixed it. So there it sat while a lot of more urgent things happened, for about 3 years now.

Finally I have felt like I can get my head above water and did some sums to see if there was any way I could make the female die (short of finding another 500 ton press). It seemed on paper that I might be able to do it with my 60 ton press so I decided to have a go at (a) trying to press a blank by using the male die and a sheet of brass on the female side to see if it looked ok and (b) play with pressing into some mild steel and see if it can be formed into the female die. Sums said in theory it would work, so inspired I rushed out to the garage and had a go.

Below are the section of coach side blank- no alignment tools so it is slightly out of whack. Still, I'm happy. Checking with some scrap steel I found the press has enough tons to form the mild steel too, so I am well pleased. Now I can start building a proper die setup! And behold! Steel coaches! Finally I can get on with it!

 

[Jordan or Plymouth Mad]

Here on Western Thunder we have long had the Back of the Class, for bodgers like me, the Front of the Class, for machine tool engineers, brass loco builders, S7* bods, etc.....
We're going to need a whole new annex to fit in a 500 ton press....

*Edit:- other True Scale disciplines are available.

 

[Matt.S.]

Now that's nifty - nice to see someone thinking outside the box

 

[Fitzroy]

Thanks Matt!
Some more progress yesterday and today- I got some mild steel blanks to use as female dies, so spent yesterday filing down the first one to get rid of the mill scale and provide a nice flat surface to press. Of course ideally I should have a surface grinder to do this, but they are expensive. I do have a friend who has one but I don't like prevailing on him too often, and he is 25 miles down the road. Anyway, I have a nice big brand new bastard file bought for flattening an engine manifold joint, so it was but the work of a couple of hours to get it down to fresh flat new metal. An upper body day. Anyway, today was the interesting bit- press it against the male die in the 60 ton press. Because the male die is slightly flexible being only 12mm thick, if I put a very thick heavy block on the bottom, with the female blank above that and the male die on top,and the ram bearing down on that, I can keep pressing away moving the ram position relative to the die set until I have pressed it locally everywhere getting enough of the tons where I need them. Since the male die is heat treated it doesn't take on any permanent set.

The next job was to drill and fit dowel pins to align the two dies. I already had 5mm holes sparked into the male die, so I clamped them together and drilled through in the drill press. The dowel pins align the dies and also align the tinplate blank in the die set.

Proof of the pudding- the finished blank pressed in the die set:- looking nice and crisp, and happily well aligned.




Here's a close-up:-




I'm very pleased with that!

The next job is to do the same with the dieset for the other end of the coach, organise the roof forming die and make a new prototype. Here is a pic of the existing prototype with blank sides. I formed the roof by hand and it was a nightmare. I definitely want a tool for that. I am very happy with the bogie dies. It should look good once all together.

 

[simond]

I just love WT…