Update: This project is now finished. Final post is here. Want to do the same thing to yours? Check the LAYZOR website.

Previous articles: part 1 – part 2 – part 3 – part 4

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When designing, I tried to limit the amount of required custum parts to an absolute minimum. Wherever possible I re-use stock parts, or I re-use an already needed custom part. That said, you’re always going to have to manufacture some new parts no matter what. Here’s what I ended up with:

All bolts are M8 size. All plates are cut from 2mm aluminium.

(Note that I have a cnc lathe and a cnc mill at my disposal. So, for me the cost of these parts is essentially zero, save the material cost. I understand that not everybody has access to these tools, so I may offer some kits for sale if there were to be enough interest.)

1. 50 x 50 x 2mm aluminium L-profile, which will become the Y drag chain rest. These are sold in 1m extrusions so it is not really a custom part, but I did cut it to size and drilled some mounting holes so I might as well add it here. It is 40cm long; the remaining 60cm will be used in a similar way for the X axis on a future air assist upgrade.
2. Adjustable bed threads (4x). Three of them are made from a 180mm M8 bolt. The fourth is a 30cm M8 threaded rod. All of them are turned to a diameter of 5mm at the end in order to fit the pulleys.
3. Adjustable Z jog wheel axle (1x). This is a 60mm M8 Allen bolt, again turned to 5mm at the end.
4. Mirror mounting plates (2x)
5. Motor mounting plates (3x). Two of them will actually have a motor attached, the third one doubles as the bearing holder plate for the 2nd Y axis.
6. Adjustable limit switch interruptor (2x).
7. Y belt attachment plates (2x).
8. Exhaust fan mounting plate (1x – 5mm plywood).
9. Adjustable bed bearing holder (1x – 5mm bore).
10. X idler mounting plate (1x).
11. Lens holder plate (1x).
12. Adjustable bed mounting plates (4x).
13. Adjustable bed bearing holder (10x – 8mm bore).
14. Limit switch mounting block (1x – 25mm black delrin).
15. Adjustable Z jog wheel (1x – 15mm aluminium).

I started milling all the mounting plates. Some went through several iterations, especially where part tolerances were important. For thin stock I usually use some WD40 as coolant because chip clearing is less important here.

 

Not really a custom part, but here’s how I mounted these small feed hole extrusions into the frame. They were too small to have one of those corner brackets.

For the M8 bolts, I really didn’t want to damage the threads because that would impair smooth bed movement. I tried using a wooden dowel, drilling a dole and using that as a buffer for chucking it in my lathe. It ended up in total failure as the wood was too soft. I then turned to those vinyl locking nuts. That was my ‘eureka’ moment of the day! Perfectly centering the threads, reusable and plenty strong.

The Z jog wheel was milled from a 15mm block of aluminium. It took a few hours to finish, and I wasn’t 100% satisfied with the result, so I re-finished it on the lathe. Then I realized I have bars of round stock with that exact diameter just waiting to be used… I don’t have a good metal saw to cut such large stock atm, but I am certainly looking into that as it would have taken me minutes to make the same part on the lathe, instead of hours on the mill… This is the only part where I really care about the finish because it is going to be on the outside of the casing.

Adding M8 thread on the inside so I can screw in the axle. I used 2-part epoxy to glue it in permanently.

 

The K40 motors come with timing pulleys, but they are not standard GT2 ones so they must be removed. This is quite cumbersome because you can’t just pry them off. I had to resort to my angle grinder for this. In the end it worked out ok without too much damage to the axle. But I wasn’t very comfortable doing it to be honest.

The motor axles are also a bit short. In order to fit both a pulley and coupler on there, I used leftover 2-part epoxy to make them into 1 piece.

 

I added small threaded holes for fastening the bearings to their mounting plate with a small locking bolt. And I sanded the limit switch fingers to a more suitable thickness.

The last part – the delrin piece – was cut from a 25mm block. I was planning on using M3 mounting bolts for the limit switch PCBs, but I ended up using hot-glue and it seems to be much easier that way.

 

That’s it for the custom pieces.