In this installment, I will show you how to attach the Y-Carriage to the frame using two 16” 8mm shafts
The inside area of the frame is 16" x 16", while the footprint is 17.5" x 18". These dimensions were chosen to accommodate 16" long 8mm steel rods and flanged supports for both the X and Y axis.
The Y-Carriage consists of the Y carrage plate, two 16” 8mm shafts, four 8mm sliding bearing trucks, and four 8mm shaft supports, as shown in Figure 1.
The Y-Carriage plate is supported by the two shafts and bearing trucks. A 8mm shaft support is used to secure the shafts to the front and rear braces.
I had to find the sweet spot for the distance between the two trucks. The further apart they are the more rigid your table will be. The down side is that you lose travel.
For this build, the trucks are 6" from outer edge to outer edge. The shafts are 8.625" apart. This seemed to work well and would result in 9" of Y travel.
In addition to the carriage components listed above, the following hardware fasteners were used to secure the Y carriage plate to the bearing trucks, and the shaft supports to the front and rear braces.
- 16, 4mm x 16mm machine screws
- 16, #8 washers
- 16, #8 lock washers
- 8, #6-32 x 1-1/2 machine screws
- 8, #6-32 hex nuts
- 8, 3/16 washers
- 8, #6 washers
- 8, #6 lock washer
Please note that I used #8 washers for the 4mm machine screws. This is only because they are cheaper than their 4mm counterparts.
The first step is to install the shaft supports as shown in Figure 2. The supports are held in place with two #6-32 x 1-1/2" machine screws. The mounting holes in the front and rear braces are all over sized at .26" in order to give the #6 machine screws some latitude for adjustments.
The screws are secured (Figure 3) with a 3/16” washer, #6 washer, #6 lock washer, and finally a #6-32 hex nut. At this point the nuts should only be finger tight. The shaft supports should look like the ones shown in Figure 4.
Next, the shafts are inserted through the rear brace and shaft supports, and two 8mm trucks are added, as shown in Figure 5.
The shafts are pushed through to the opposite side and secured with the set screws on the shaft supports, as shown in Figure 6.
The Y-Carriage plate should be created from a piece of 3/4" stock. I recommend melamine coated particle board. The plate has four holes for each truck and two holes in the middle to mount the ACME nut. Several additional holes were added for attaching the table later. The truck and ACME nut holes have a 3/8” pocket so that the heads of the hardware wont interfere with the table (Figure 7).
The plate is secured to the four trucks with 16, 4mm x 16mm machine screws. A #8 washer/lock washer combo is also added, as shown in Figure 8.
Once the carriage plate is secured to the four trucks, move it all the way forward and tighten the front supports. Next, move the carriage plate to the rear and do the same. Once you are happy with the movement of the carriage, tighten all the nuts.
This completes the Y-Carriage assembly. If you are building along with me, your machine should look like the one shown here.
The drawing files for the the Y-Carriage can be found here:
Please note that these files are subject to change. You will need some sort of CAD software that can import eps or pdf files to use them. They are raw 2D drawing files without annotations.
Please note that there are cheaper linear motion components available. These are the ones I used. Almost all shafts and supports will works, but dont cheap out on the bearing trucks, as you get what you pay for.