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Z-Axis with AEG router

precise-z-movement

#1

I am working on my Maslow second build - MarkII and here is my take on Z-Axis


First I removed a factory lead screw and plastic fixture - it was wobbly, hard to turn and allows loose movement of router. Thread is 4mm, way to coarse for z axis.

Next I printed three knobs/washers to center T8 x 2 lead screw.


I drilled and taped four M3 threads - be careful when drilling - very small tolerance!

Next I sanded and polished holder and router to minimise friction;

And here is complete assembly

Works like a charm allowing easy removal of router;

I think that the same router is sold in US/Canada under the Ryobi/Rigid name: T8 lead screw with washer is available on the net for example http://bit.ly/2FzCfZK
If you like it I can send you stl files of washers or let mi know how to make it available in our forum.


#2

Nice build!
What is you Z pitch setting now?


#3

2mm per turn - I also tried 1mm per turn, but it is overkill - too slow.


#4

Don’t get me wrong please.
My c-beam has 4 lead and 2mm pitch, giving a travel of 8mm per rotation. With gears I made it 10mm.
With the original motor.
With your mod, wouldn’t it be possible to speed Z up rather then slowing it down?
Edit: https://www.aliexpress.com/item/DuoWeiSi-3D-Printer-Parts-3Pcs-3D-Printer-T8-1mm-100mm-Lead-Screw-8mm-Thread-With-Copper/32822890730.html


#5

Sorry Gero - I do not quite get it ;-(( As I understand I have screw with one lead, 2mm pitch, giving travel 2 mm per rotation. That value I’ve entered to GC. I hope that I am not mixing something.


#6

I don’t have the AEG router, nor the Ridgid. I may be wrong. The default setting is 3.17mm. If you have 1 lead, you slowed it down a bit. With 4 lead you could have a bit more then doubled it, I think.


#7

Tom, this looks great. One question, in your pictures are there two different lead screws shown? If so can you give the specifics of each. Thanks.


#8

If I read @Gero 's link correctly, it might be possible to have up to 14mm per turn just by swapping the screw and the nut? That would be a very compact translation amplification! When amplifying tough, I wonder how much the router base mechnical drag could still be overcome with the stock Z motor and arduino shield H-Bridge.

Note: I have the Rigid (Ryobi) canadian edition. I did setup a screw with a modified C clamp.

And here is a bearing roling on the frame, slid on the pry bar to keep pressure on the tab toward the router body.

Note the brass bushing to get a snug fit and prevent frame wear. Sliding the bushing to remove it also allows the screw to be pulled and tiped out of the frame for (dis)assembly.

Was quite a machining job and yet have only 2.5mm per turn. It is very reliable but I am definitely looking for a faster solution. :roll_eyes:


Max plunge rate for simulation
#9

How many :heartbeat: s can I give this post? I have been trying to catch your bearing idea for quite a while! I wish I could see the clamp more clearly. How easily does it detatch for maintenance?


#10

Release is a snap: pinch the paper clamp, let the bearing slide 1/8" along the axis and the pry bar is released, the router body slides freely.

The pry bar is then loose. It is a modified spade drill bit pinched between a custom keying tab and the cut C-clamp body.

The Keying Tab is a general particle board anchor I found at the hardware store, then milled to fit snugly into the router body key slot.

Keying_Tab_blank

Additional note: I also waxed the sliding body surfaces to reduce friction. And I use the tube cap trick with bungee cords to keep avoid backlash: (Showing here the chain snap protection simulation)


#11

I’m a fan.
This is the best I have come up with:


I am loving @TomD 's topic and @c0depr1sm 's input.
As much as I would like to build a meticulous z axis I feel like this is more my speed using what I already have to its best capacity.
Honestly I’m tempted to use an old Black & Decker router that has rack and pinion depth adjustment on it with a knob that could be replaced with the motor. What do you guys think?


#12

Good eye @michaelsen ;-)) Yes I experimented with T8x1 (one lead, 1 mm pitch) but it was too slow. I ended with T8x2 (one lead, 2mm pitch)


#13

When seting up my Z axis, I came to a point I wanted to replace the motor/gearbox to increase speed. I needed to measure how much torque the gearbox has to overcome. That is because these things are sold from catalogs listing speed and torque.

I later considered it was a bad idea to increase motor size with higher electrical current load on the shield. That is because there is only so much power the genuine shield can handle. At the risk of overheating.

Coming back to torque: I wanted to measure the needed motor torque. So I disconnected the motor/gearboxx from the shaft coupler. I wrapped a wire around the shaft coupler and attached a bottle filled up of water to try to figure out how heavy the bottle needed to be to start turning the router screw.

There is some initial torque (static friction to overcome), then it can move with less torque. In my case it was in the order of 2.7 kg.cm. Barely turning.

That is why I carefully waxed and adjusted the router clamp latch to not hold the router body and yet not let the router body move sideways (affecting the bit position).

Now that screw thing above is definitely something I want to try tuning.


Accurate MaslowCNC manual calibration, how to
#14

Note: On the picture of your router base, there is no clamp. In my experience with the Rigid, I needed to use it and adjust it carefully to prevent the router to move laterally or vertically into the base during operation.


#15

I actually removed the clamp from mine and replaced it with a nut and hex head bolt. This way at I can just use an Allen wrench to adjust it instead of the painstaking OPEN THE CLAMP, ADJUST SCREW, CLOSE CLAMP, OOPS TOO TIGHT, OPEN CLAMP, etc. Can you tell I got annoyed? :roll_eyes: Anyway it’s just a part of the evolution of my machine. It’s way easier now.:grin: