Problem building Duclos' "Little Blazer"

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jrlandau

Member
I'm trying to build this beautiful little engine, working from the description and plan in Projects in Metal magazine for June 1992. At the start of the project, a 7/8" end mill is to be used to cut the main curved surface of the engine body. The problem is that there doesn't seem to be enough room for the cut. I have stared at it for quite a while but don't know what I've done wrong.

BUT--I've found what may be a problem in the instructions. One of the first things to do (on the first page) is to "Proceed by milling a 20 deg. angled surface on one of the long sides (1-7/8") of the block." But the table of Finished Sizes (15 pages later) calls for the engine body to be 1-5/8 x 1-5/8 x 1-7/8. This seems to be a contradiction (are there 2 long sides and a short or 2 short sides and a long), and a change might solve my problem. But perhaps there is an operation that I have missed that changes the size of the engine body. Or I've made some other error. I'm hoping someone who's done this can straighten me out.

I wonder if you have an answer yet.
I'm looking at the plans for Little "Blazer" Engine in "Two Shop Masters." The main body block is 1.625" square in the top view (to start) and 1.875 high. The 20-degree angle is milled on one of the 1.875" sides. If you are looking at that face, it is 1.625" by 1.875" and the 20-degree angled surface determines which way is up.
The table you speak of says "finished sizes" but they are really the size a block needs to be to make the part. You probably couldn't hold it to work on it, but you will need that much. A little way down the list is 1"x1 1/2" round stock for the cylinder. In photo 20, he is turning the cylinder from something bigger diameter and longer, when it's finished it is no longer round but its major dimensions are 1.000 by 1-1/2 inches. (Strange mix of fraction and decimal dimensions, but those were the times.) That list seems more often to be called "Bill of Materials". It also includes fasteners.
The 7/8" end mill cut is made parallel to the 20-degree face and it says it is 1.210" from that face to the crankshaft center, so there is plenty of room for the
7/8" slot.
I hope this helps if you haven't already figured it out.
Doug

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