Making the Dropouts
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Making the Dropouts
The next steps after completing the main frame are fabricating dropouts and attaching them to the rear chain stays and the mounting everything to the main frame. The reasons for the few months delay in writing this article is that the initial design did not work so back a square. I already took photos so there is some jumbling of steps; not all look the same; but show the general processes anyway. I will explain more as we go along.
This is a dimensional drawing of the initial design.

The problem with the original dropout design was that the chain rubbed the rear stay in the 2 smallest cogs, so it was redone. However this 2nd design which I used isnít satisfactory either so it will be redesigned in the next frameset. The work is similar regardless of the exact dropout dimensions, so here are the photos.

The steel as been sanded to smooth the rough finish to the sheet and the layout lines will show better.
The next step is to coat the parts with Machinistís layout dye. This is a lacquer and uses lacquer thinner to remove.
Now a scribe is taken and the lines for drilling and cutting the right side dropout with the deraullier are made. 
Then the same is done for the left side. 
Now a center punch is used to mark all the pertinent junction lines to start the drill bits properly. 
Placing the prepared plate in the drill press using a cross slide vise. This vise travels in both directions, so the vise will move the plate.
First a slight cut is taken to accurately locate the holes and than are enlarged to the proper dimension. 
Tapping the threads for the rear deraillleur is next. The start hole is drilled to 8.4mm. 

Proper use of the tap is to turn about ľ turn and then back out and turn clockwise another ľ turn after initial start. Use lubricating oil. 

Once all holes have been drilled out and rear derailleur tapped, they are ready to be cut out. 

Here I have taken the right side plate and placed and tightly clamped into a bench vise. A hacksaw is used to make the cuts. A word about tooth counts on the blades, 18T is for rough cuts and is a bit difficult to start but will remove material faster; 32T is for finer cuts and generally used to cut thin sheet metal; 24T seems to be the best all around blade for cutting .190 sheet and is what I use. Actually any will work, just use PLENTY of cutting oil.  

The piece in the rotated in the vise and the long cut for the rear derailleur is done. Use care when making this cut to avoid either cutting in too far for leaving excess material to remove. To make the blade move to either the left or right, lean the handle. This makes the blade turn direction to follow layout lines. 
To start cuts that are not perpendicular to the edge you take a light cut that is perpendicular and the angle the blade in the proper direction; this light cut holds the blade to get the cut started.
This shows the dropouts to ready for the next step. I know it may seem like a hard job, but it really doesnít take that long. These 2nd design dropouts are a bit complicated and I will come up with something simpler on the next design, honest.
Next - Making the Stays  

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