JimG
Western Thunderer
Plastikard Coaches for Banavie Road
Banavie Road will need some coaching stock and I wanted a rake of the Drummond four wheel suburban stock. In S scale that usually means scratchbuilding unless you can find an etch kit that you can get re-scaled and are willing to pay the price. I had got original drawings from the NRM last year and had made my own drawings from them. So I reckoned to start scratchbuilding using Plastikard as I've done before, and using the late David Jenkinson's methods.
So I made a start - actually as a demonstrator on the S scale stand at Railwells last year. The results were not all that great but i never expect all that much on demo efforts since you are normally being distracted all the time, if not by members of the public at least by your fellow demonstrators. Later in the year I junked the Railwells efforts and started afresh, only to find that my efforts were still not very good. Maybe it's just advancing age, or maybe I'm just getting more pernickity in my old age, but the results didn't look all that good to me. So that put me in a bit of a quandary. I needed panelled stock on the layout - if not the wee Drummond four wheelers, at least some McIntosh bogie stock. Was I going to have to go down the etched brass road however I did it, or was there another way.
I just happen to have a CNC milling machine - got for another purpose - and I wondered about using that, I had heard that milling styrene was a no-no since the heat in the cutter started melting the styrene and making a mess of any cut. But I had picked up on the Internet that using carbide cutters got round this problem, so I did a bit more digging around on Google and came up with a contact in the G1MRA who had milled some freight sides from Plastikard. So I dug up his email address and we had a fruitful exchange of information and I set up to try out the method on panelled sides.
The Drummond stock has panelling on the lower sides of the body - rather like Gresley teak stock. So I decided to deal with a side as an upper and a lower part to cut down the milling required. I've been doing a fair bit of messing around, experimenting with various combinations of feed and speed with the cutters, and also working out the best way of setting up the project so that it takes the shortest time. My first attempt at complete set of coach sides would have taken well over twelve hours to complete - for a small 28' 6" coach. I'm now getting times down into the one to two hour bracket, but there is still a fair bit of experimentation going on.
Here's a test that I did today - one side of a one compartment test coach side.
The lower side fits on the lip on the bottom of the upper side. The rough edge on the right side of the drop light is where I have pushed things just a bit. I decided to incorporate a drop light at teh last moment and made it about five thou thick and at that thickness it looks as though the cutter has started picking at the edge and distorting it. It looks as though I will need to increase the thickness of the drop light by a thou or two to avoid this. However, the rest looks good - certainly a lot better than my earlier manual attempts.
Here's the setup
The mill is a Seig KX1 and it is controlled by Mach 3 software on a pretty basic PC running WinXP. The work table on the mill is a piece of Contiboard bolted onto the table to give a smooth surface for double sided tape.
A closer shot of the milling head with the 1mm diameter cutter at work, These cutters are a bit fragile hence the experimentation to find feed and speed settings which don't break the cutter.
I'll now set up to do a full set of sides - two of each of the upper parts and the lower parts.
Jim.
Banavie Road will need some coaching stock and I wanted a rake of the Drummond four wheel suburban stock. In S scale that usually means scratchbuilding unless you can find an etch kit that you can get re-scaled and are willing to pay the price. I had got original drawings from the NRM last year and had made my own drawings from them. So I reckoned to start scratchbuilding using Plastikard as I've done before, and using the late David Jenkinson's methods.
So I made a start - actually as a demonstrator on the S scale stand at Railwells last year. The results were not all that great but i never expect all that much on demo efforts since you are normally being distracted all the time, if not by members of the public at least by your fellow demonstrators. Later in the year I junked the Railwells efforts and started afresh, only to find that my efforts were still not very good. Maybe it's just advancing age, or maybe I'm just getting more pernickity in my old age, but the results didn't look all that good to me. So that put me in a bit of a quandary. I needed panelled stock on the layout - if not the wee Drummond four wheelers, at least some McIntosh bogie stock. Was I going to have to go down the etched brass road however I did it, or was there another way.
I just happen to have a CNC milling machine - got for another purpose - and I wondered about using that, I had heard that milling styrene was a no-no since the heat in the cutter started melting the styrene and making a mess of any cut. But I had picked up on the Internet that using carbide cutters got round this problem, so I did a bit more digging around on Google and came up with a contact in the G1MRA who had milled some freight sides from Plastikard. So I dug up his email address and we had a fruitful exchange of information and I set up to try out the method on panelled sides.
The Drummond stock has panelling on the lower sides of the body - rather like Gresley teak stock. So I decided to deal with a side as an upper and a lower part to cut down the milling required. I've been doing a fair bit of messing around, experimenting with various combinations of feed and speed with the cutters, and also working out the best way of setting up the project so that it takes the shortest time. My first attempt at complete set of coach sides would have taken well over twelve hours to complete - for a small 28' 6" coach. I'm now getting times down into the one to two hour bracket, but there is still a fair bit of experimentation going on.
Here's a test that I did today - one side of a one compartment test coach side.
The lower side fits on the lip on the bottom of the upper side. The rough edge on the right side of the drop light is where I have pushed things just a bit. I decided to incorporate a drop light at teh last moment and made it about five thou thick and at that thickness it looks as though the cutter has started picking at the edge and distorting it. It looks as though I will need to increase the thickness of the drop light by a thou or two to avoid this. However, the rest looks good - certainly a lot better than my earlier manual attempts.
Here's the setup
The mill is a Seig KX1 and it is controlled by Mach 3 software on a pretty basic PC running WinXP. The work table on the mill is a piece of Contiboard bolted onto the table to give a smooth surface for double sided tape.
A closer shot of the milling head with the 1mm diameter cutter at work, These cutters are a bit fragile hence the experimentation to find feed and speed settings which don't break the cutter.
I'll now set up to do a full set of sides - two of each of the upper parts and the lower parts.
Jim.