Well guys the time has come for my first engine project to get under way!
I was given the plans about a month ago by a friend and have with your help identified said plans as an Elmers #25. Now I feel sure that many of you old hands will identify with many of my misgivings but only time will tell if this is a good starting point. I intend to use this project as a means whereby a "good" approach strategy to building may be formulated and adopted, so with this in mind here goes and forgive the ramblings!
It goes without saying "Please feel free to comment/criticize or suggest for future reference any better methods.
Examination of the plans quickly revealed the first snag , being drawn in Imperial dimensions all of the threads specified are non -existant in my workshop so a snap decision was made to covert all #5-40, and #2-56 threads to 3mm coarse (I have a boxful of metric cap-head screws on the shelf as well as the requisite taps and dies) although I will work in Imperial as far as the main dimensions are concerned .
The plans show 11 engine component parts + a jig for drilling the inlet and exhaust ports and an associated locating pin, also listed is a spring and a nut to restrain said spring on to the pivot.
As is my habit when modelling (boats) I made detailed individual c**p-o-cad drawings of each component . (I have a chalkboard slate for this purpose )This may for many of you seem OTT but I find it helps "fix" each bit in my mind and often throws up potential snags that might be encountered whilst manufacturing.
The Frame was the first component to be tackled and in the absence of a mill at the time it was made by hand, fairly straight forward to fabricate from the drawing, I filed the top of the frame flat and square and used this surface as a reference to mark out using a height gauge the operating centre line for the pivot and bearing, all the holes were drilled using the drill press (still no mill at this stage) and both sides flatted (using wet n dry on my new ref. surface) and polished.
(The material available was 3/8" not 1/4" thick as specified and make a mental note that the crankshaft and bearing dimensions must be modified to allow for the substitution).
I find that the "handwork" exercise not only very satisfying but keeps the skills acquired so long ago, alive, as well as providing exercise ( a lot better than jogging!).
Next operation with a little time to spare (out of sequence with instruction sheet but with the mill imminent shouldn't make much difference.) was to turn and fit the bearing from an off cut of bronze (I think it's been in my oddments box for 40 yrs+ in the knowledge "it will come in handy someday" and the end result is shown below
I was given the plans about a month ago by a friend and have with your help identified said plans as an Elmers #25. Now I feel sure that many of you old hands will identify with many of my misgivings but only time will tell if this is a good starting point. I intend to use this project as a means whereby a "good" approach strategy to building may be formulated and adopted, so with this in mind here goes and forgive the ramblings!
It goes without saying "Please feel free to comment/criticize or suggest for future reference any better methods.
Examination of the plans quickly revealed the first snag , being drawn in Imperial dimensions all of the threads specified are non -existant in my workshop so a snap decision was made to covert all #5-40, and #2-56 threads to 3mm coarse (I have a boxful of metric cap-head screws on the shelf as well as the requisite taps and dies) although I will work in Imperial as far as the main dimensions are concerned .
The plans show 11 engine component parts + a jig for drilling the inlet and exhaust ports and an associated locating pin, also listed is a spring and a nut to restrain said spring on to the pivot.
As is my habit when modelling (boats) I made detailed individual c**p-o-cad drawings of each component . (I have a chalkboard slate for this purpose )This may for many of you seem OTT but I find it helps "fix" each bit in my mind and often throws up potential snags that might be encountered whilst manufacturing.
The Frame was the first component to be tackled and in the absence of a mill at the time it was made by hand, fairly straight forward to fabricate from the drawing, I filed the top of the frame flat and square and used this surface as a reference to mark out using a height gauge the operating centre line for the pivot and bearing, all the holes were drilled using the drill press (still no mill at this stage) and both sides flatted (using wet n dry on my new ref. surface) and polished.
(The material available was 3/8" not 1/4" thick as specified and make a mental note that the crankshaft and bearing dimensions must be modified to allow for the substitution).
I find that the "handwork" exercise not only very satisfying but keeps the skills acquired so long ago, alive, as well as providing exercise ( a lot better than jogging!).
Next operation with a little time to spare (out of sequence with instruction sheet but with the mill imminent shouldn't make much difference.) was to turn and fit the bearing from an off cut of bronze (I think it's been in my oddments box for 40 yrs+ in the knowledge "it will come in handy someday" and the end result is shown below
