Reviving an 1870s printing press (part 2)

Part 2
Making things harder than they should be
If you read part 1 of this fascinating series, you know that I had to make a chase base for a 19th-century letterpress machine.

I started by measuring every part of the press that would hold the new chase bed. The goal was to have a press that would eventually use a standard open chase that would bypass the hard-to-get closed chases.

Here's a bit of my sketching and dimensioning and notes and corrections, all scribbled on two sheets of my Department of the Navy memo pads.

A simple approach
After a few days of making prototypes from plywood and trying to make things fit, I realized I was doing more work than necessary; all I really needed was a simple rectangular base. 

NOTE: Some of the following information is not correct if you use newer 6X10 chases for later Kelsey presses (as I did). See my later blog (part 4) about lowering the chase. JHS

If you're doing this at home, the size should be about 6.75" X 11.625", and about 3/8" thick. I used aluminum. It will look something like this when mounted in the press (without the chase). You should see two cast-iron shoulders that support and position the chase base. They are located near the center of the bed, a few inches apart. They are hidden in this view.

The chase will be supported by two steel angle tabs, visible at the bottom-left and -right of the base. These two tabs are the exposed legs of steel 1" X 1" angles, cut about 2-inches long. I used J-B Weld epoxy to attach them to the back of the chase. See more details below:

Position the two angles to avoid conflict with  two cast-steel shoulders on the base.
The aluminum base is resting on and hiding these shoulders in this photo.

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Details of the steel angles for supporting the chase. Leave enough space between them to clear the cast-iron shoulders on the press.

Two tabs (angle legs) at bottom edge of chase bed

The steel angles are attached with epoxy to the back surface of the bed

At the moment, the epoxy seems very capable, but I may decide to drill through and use machine screws and nuts to strengthen it. In any event, the two tabs are a good support for the steel chase, as shown below.

Steel chase supported with angle tabs

DETAIL: Angle tab at lower-left corner of chase

Next: Reworking (or replacing) the spring-loaded clamp bolts