B
Bogstandard
Guest
Here again is one of my long winded explanations on how I make bits for my engines just to make them that little bit different.
For basically to get an engine to run I just soft solder my pipes to it and get it to run. When I come to finish off an engine I always try to fit flanges on the inlet and exhaust pipes, for two reasons, the first is that it is easier to take an engine apart and reassemble, and the other is that the full size engines would most probably have flanges of some sort.
Mine aren't true scale but they are easy to make and look OK.
To start I have come up with a rule that gives fairly good proportions, I call it my 50 thou rule. The main flange itself is about 50 thou thick, the width and the height of the sticky up bit is about 50 thou plus the diameter of the pipe, that is if the pipe is 1/8" then the height and width will be about 0.125"+0.050" = 0.175" (or somewhere nearabouts). Thats the technical bit out of the way.
The flange is just an easy turning job, and I make at one time however many are required for the engine. To get the overall width of the flange you have to either draw it up, or for those who like to do things on the run as I do, make the flange larger than needed then put one of the fixing bolts as in the pic until it looks right, and you have a bit of turning room for the bolt between the sticky up bit and the edge of the flange. Then once you have done one, turn all the others to the same diameter.
This second pic shows a parallel being used to find the edge of the vice jaw, then measure the diameter of the flange and move the jaw half that measurement to get you into the centre of the flange. Zero your machine handles.
Put the original sized drill into the chuck, put a couple of parallels into the vice, place the flange onto the para's and feed the non turning drill into the original hole, tighten up the vice, This will centralise the part ready for drilling.
Offset either side of zero and drill the two mounting holes. Rezero and use the drill again as above in pic 3 to centalise the next part to be drilled and repeat as necessary.
Now this is where the slicky tricky bit comes in. Remove the para's, get TWO drills of the same size as you have just used to drill the mounting holes, stick them in the holes you have drilled and put the bits into the vice as shown in the pic with the drills resting tightly on top of the vice jaws, don't tighten up too much as you will distort the sticky up bit, but enough to hold it while gently milling. When milling don't use a big cutter, use very light cuts of about 5 thou and come from the side, not from the top, and please NO CLIMB MILLING. I lock my cutter at the finished height (about 15 thou from the central boss). Once you have finished one side, just turn it over and do the other.
This shows the two I have just done for finishing off my mine engine.
With these flanges I don't do any drilling of the engine until they have been soldered to the pipe, except to put a relief drilling in the engine inlet and exhaust holes of the same size as the pipe diameter, only about 1/16" deep.
I have the pipe sticking out of the flange by about 20 thou, and then solder where the pipe enters the flange, this stops solder from holding the flange off the port faces. Once it is soldered to the pipe then put the 20 thou protrusion into the relief hole on the engine ports and spot thru the holes when the flange is in a suitable position. Drill mounting holes on the engine, put a bit of sealant onto the flange and assemble.
It has taken me longer to make this post than to do the whole job.
John
For basically to get an engine to run I just soft solder my pipes to it and get it to run. When I come to finish off an engine I always try to fit flanges on the inlet and exhaust pipes, for two reasons, the first is that it is easier to take an engine apart and reassemble, and the other is that the full size engines would most probably have flanges of some sort.
Mine aren't true scale but they are easy to make and look OK.
To start I have come up with a rule that gives fairly good proportions, I call it my 50 thou rule. The main flange itself is about 50 thou thick, the width and the height of the sticky up bit is about 50 thou plus the diameter of the pipe, that is if the pipe is 1/8" then the height and width will be about 0.125"+0.050" = 0.175" (or somewhere nearabouts). Thats the technical bit out of the way.
The flange is just an easy turning job, and I make at one time however many are required for the engine. To get the overall width of the flange you have to either draw it up, or for those who like to do things on the run as I do, make the flange larger than needed then put one of the fixing bolts as in the pic until it looks right, and you have a bit of turning room for the bolt between the sticky up bit and the edge of the flange. Then once you have done one, turn all the others to the same diameter.
This second pic shows a parallel being used to find the edge of the vice jaw, then measure the diameter of the flange and move the jaw half that measurement to get you into the centre of the flange. Zero your machine handles.
Put the original sized drill into the chuck, put a couple of parallels into the vice, place the flange onto the para's and feed the non turning drill into the original hole, tighten up the vice, This will centralise the part ready for drilling.
Offset either side of zero and drill the two mounting holes. Rezero and use the drill again as above in pic 3 to centalise the next part to be drilled and repeat as necessary.
Now this is where the slicky tricky bit comes in. Remove the para's, get TWO drills of the same size as you have just used to drill the mounting holes, stick them in the holes you have drilled and put the bits into the vice as shown in the pic with the drills resting tightly on top of the vice jaws, don't tighten up too much as you will distort the sticky up bit, but enough to hold it while gently milling. When milling don't use a big cutter, use very light cuts of about 5 thou and come from the side, not from the top, and please NO CLIMB MILLING. I lock my cutter at the finished height (about 15 thou from the central boss). Once you have finished one side, just turn it over and do the other.
This shows the two I have just done for finishing off my mine engine.
With these flanges I don't do any drilling of the engine until they have been soldered to the pipe, except to put a relief drilling in the engine inlet and exhaust holes of the same size as the pipe diameter, only about 1/16" deep.
I have the pipe sticking out of the flange by about 20 thou, and then solder where the pipe enters the flange, this stops solder from holding the flange off the port faces. Once it is soldered to the pipe then put the 20 thou protrusion into the relief hole on the engine ports and spot thru the holes when the flange is in a suitable position. Drill mounting holes on the engine, put a bit of sealant onto the flange and assemble.
It has taken me longer to make this post than to do the whole job.
John
