The Center Foot

Mechanical Parts

There are several parts that you will need to complete the Center Foot Assembly.

The Caster
Colson Caster - part number
it's on page 26 of that catalog, or search by the part number.
There are lots of vendors for Colson casters.
I bought mine on eBay from
they sell it as:
QTY 1 - Colson Swivel Stem Caster with 3" Performa TPE Gray Non-Marking Wheel 1-3054-441
they take "best offers" at between 10% and 15% less than their asking price
and they do not charge much for shipping, no minimum order.
Note: if you are thinking of using my design for the outer feet then you might want to purchase the wheels at the same time.
The larger the order the bigger discount you are likely to get and you only pay for shipping once.

The Shoulder Bolts
Shoulder bolts, Allen, Alloy steel black oil finish, 3/8" shoulder (5/16"-18 thread) x 1/4"
QTY 2 - Bolt Depot part# 14069

The Aluminum Spacer
Used as an insert the spacer goes into the Center Ankle to hold the shoulder bolts.
QTY 1 - Aluminum Spacer #AS38-14-64 For  1/4" or 6mm bolts 
OD = .375 (3/8") 9.53mm
 ID = .257 6.53mm
 L = 1.000 (1")  25.4mm
curiously enough the ID on this spacer (.257 in.) is exactly the size you would have to drill in order to tap it for a 5/16"-18 thread.
You may also be able to find a threaded spacer.
Note: if you don't want to buy a 5/15-18 tap just for this project send me email. I'll tap one for you and include it with your order.

The Magnets
QTY 10 - Dimensions: 3/8" dia. x 1/16" thick - Grade N52 - K&J Magenetics part number D61-N52
buy lots, you need 4 at a minimum, but they are fragile and easy to loose. (also used in the outer foot!)
 I started with
Dimensions: 1/4" dia. x 1/16" thick -
Grade N52 - K&J Magenetics part number D41-N52
then went larger for
a stronger grip

The only unusual tool is a 5/16"-18 tap. If there are
You should already have almost everything else I use during the assembly process.
I show a corner clamp being used to assemble the apron but it can be glued together without it.

I used both Weldon #3 and Weldon #16 cements for the assembly. Each at different points in the assembly process. You should use both, or equivalent cements.
I used Squadron Green Putty - it also comes in white. It's easier to see the green against the white styrene. There are obviously lots of other suitable products.

A Note on suppliers cited
I have no relationship with any of them, except as a satisfied customer. Most were chosen because of their low prices, no minimum quantity order requirements, and cheap shipping.