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The Meticulous Z-Axis


#101

Thanks Bryan. I will take care of this after work tonight. I also took pictures of my setup so I can show you the ring setup. I did have to make a couple of minor modifications in order to get things to fit/work and I can share that with you as well.

Thank you for your help with the details.


#102

I reset the Z axis pitch and for my application it turned out to be -15.087. Good call on that one!!! With that setting, I was able to achieve 5.01mm when I set it to travel 5mm. I’m going to call that close enough.

I test ran the Maslow without cutting anything and I found a few adjustments I need to make. The sled was snagging on the surface so I sanded down the bottom surface, rounded the edge and applied a few coats of shellac. My thought then is I can wax the bottom if needed.

I had to raise the height of the ring as this application seems to have a higher center of gravity than the “original” sled. (I won’t say “stock sled”).

So far tho, it seems as if it is going to work well. I will try a live test soon. Looking forward to that!


#103

Now we’re getting somewhere! :smiley: That’s great news! Also means I may have measured the lead wrong on the screw, but at least now we know. :wink:

I have a 1/4" sheet of HDPE (low-friction plastic) on the bottom of my sled to reduce friction and I noticed an increase in machine accuracy when I started using it. Anything to help make there be less friction between the sled and the work-surface is a good thing.

The high center of mass was something that I’ve been concerned about. I was thinking of adding steel weights down at the bottom of the sled to help lower the CoG. Do you mind weighing the sled for me? I know the ideal weight of the original sled was somewhere around 25 lbs. I’ve been running around 35 lbs myself, so long as we don’t go over that the motors should be able to handle it.

Me too! I can’t wait to finally see this in action. :smiley: Good luck with the live test.

Thank you so much for helping test the design. I really appreciate the input!


#104

I don’t think the center of gravity being high is anything to be very concerned
about. As long as you attach the chains near that CG you should be good.


#105

Agreed. It’s not “concerning” in the way that keeps me up at night, more just something that I was trying to mitigate as much as possible.


#106

I weighed my sled. It is 18 pounds. Hmmmmm…your is almost double the weight of mine. So far, I have not added weight to it but am now wondering if I should add some. Has anyone determined what/if there is a min. weight for the sled?

Be aware with the CoG thing because as you raise the CoG, the chain (at the sled) moves further away from the table thus causing side tension on the gear at the motor. This caused the chain to skip or wrap around the sprocket. I know this because I had this issue and the only way I solved it was to remove the stretchy string and replace it with counter weights.

Here is a picture of my sled setup.


Z-Axis upgrades Consolidation
#107

I weighed my sled. It is 18 pounds. Hmmmmm…your is almost double the weight
of mine. So far, I have not added weight to it but am now wondering if I
should add some. Has anyone determined what/if there is a min. weight for the
sled?

see the spreadsheet that we developed a couple of days ago

heavier is better, until you get too heavy to work in the top center

Be aware with the CoG thing because as you raise the CoG, the chain (at the
sled) moves further away from the table thus causing side tension on the gear
at the motor. This caused the chain to skip or wrap around the sprocket. I
know this because I had this issue and the only way I solved it was to remove
the stretchy string and replace it with counter weights.

move the motors out to match the height on the sled with your normal workpiece
thickness.

some people are making the top beam adjustable to deal with this, some people
are pushing the top beam out and using extra thick spoilboards when working with
thin stock.


#108

There is a spreadsheet???
In what section do I find that?


#109

see the topic

David Lang


#110

OK…If I understand this spreadsheet, I should have a 20lb sled. My configuration is the stock one. I’ll add a few pounds.


#111

@huntleybill: So good to see the sled built! It looks pretty close to the way I had envisioned it, which is always a good thing :wink:

Quick couple of questions.

Did you 3D print the spindle clamps? How are those secured to the Z-Carriage? I would imagine you used a heat-set threaded insert or something. I know David and I were talking about how the plywood version might want to snap, and I think your solution is a pretty good one. Of course, it makes us even more reliant on having a 3D printer to make parts, but alternatively someone could machine them from a block of acrylic. It will just be more expensive to manufacture.

I can see part of the spine broke off during machining. What type of plywood did you use? I had designed it around Baltic birch for a little more strength, but even still I’m starting to worry that those are too thin. We could always remove the inside cut-out for more strength.

@Dlang: I hadn’t seen that spreadsheet before. That’s pretty good data.

I know I had gone for a very heavy sled because at the time the firmware didn’t account for chain sag, so that was my solution to reduce the amount of chain sag. Also helped my smaller-than-stock machine maintain some semblance of accuracy in the bottom corners.


#112

I have attached a few pictures for your review.

My Maslow was not cutting the pieces for this very accurately. The router clamps were pretty much useless so I made them using my 3D printer. I mounted them to the Z-carriage by drilling deep holes and tapping them with M4 tap. I secured them with M4 screws and they seem to hold pretty good. To be honest, I am weary of how long this will hold up so I plan on keeping an eye on it.

Maslow cut the rest of the pieces out ok,not great but ok. You can see in some of the pictures that the joints are not all that pretty. There are gaps and I had to spend some time filing/cutting/sanding to get the joints to fit together… and they still aren’t tight fitting. Good thing we have glue!! I think all these parts could also be easily cut out using a scroll or band saw. Even the clamps.

The broken off “looking” spine was more my fault. I did not align the plywood correctly and the router partially moved off the end of the plywood. With the supports and the glue, the pieces are rock solid so I didn’t worry about the missing area.

Also, I had to put a 3/8" filler piece in between the motor mounting plate and the frame in order to get the belt to fit. I used all the parts suggested from the BOM. The belt was a little too long but the 3/8" filler did the trick. Different pulleys may require different size fillers.

Finally, there is a picture of the ring. I pretty much just centered it around the router and as we discussed before, raised the center of gravity and so far, it seems to work just fine.

As a side note, I did not use heat set inserts on anything (even the dust chute). I just drilled and tapped the holes. Worked fine.

It doesn’t look pretty but so far, it seems to work. I’m gonna try and cut the Maslow Logo as the first live full test tonight.

I’m sure you have other questions so ask away.


#113

Well, @Dlang, you were right. You had cautioned that people’s machines may not be cutting accurately enough for some of the parts. I’m pretty sure that I can get my machine to the point where accuracy shouldn’t be too much of an issue, but I can see where this could be a problem.

In the new files I’ve made to accommodate the improved dust chute I made the plywood clamps twice as wide, so here’s hoping they work a little better. Otherwise, I’ll probably just do as you did and print them too.

I guess the good news I can take away from this is that the sled can still be built even if the Maslow isn’t super accurate. It will just take more post-processing work to do so.

That certainly is a solution to the problem. With enough infill, printed clamps will most certainly be stronger than the plywood. I know that you can drill and tap the plastic and it’s fairly reliable, but in this specific application I would recommend getting some heat-set threaded inserts like these. You can torque the bolts a bit more with these, and given the forces that the spindle will be under that would be very helpful.

While it is structural, that part is mostly for overkill. I wanted to cut down on the possibility of the spine racking while cutting, but the whole thing is made from 3/4" plywood, so it already is plenty strong. I was mostly just worried I had made it too narrow and they would just break on everyone’s sleds. I may still remove the void, however, since I did it mostly for style and it might still be a failure point.

I had intended to mount the Z-Axis motor off to the side to tension it, but I must admit I kinda like your solution. Maybe when I get into the revisions in the future I’ll devise some screw-type tensioner for the motor.

Good job with this, I’m really happy to see a built sled! I can’t wait to hear how well it fairs. :smiley:


#114

if the new parts can work better than the old ones, you can use them to cut a
second set of parts that are more accurate.

we are hauling ourselves up with our bootstraps.


#115

I put on a well used piece of 1" Styrofoam and milled out the logo. It worked perfectly. I thought it was freak accident that it worked so I tried it again. It worked perfectly. Next I’m going to try it on a piece of wood!!

Observations:
The Z axis moved smoothly without any slop or up and down play. Nice!

If you recall, I have no added weight and the sled moved smoothly throughout the whole process. No chain sag or skipping. (Then again I am only cutting Styrofoam).

I have a 1 1/4" 8 foot hose I use on my sander to collect dust and I found that the suction was inadequate at the router, I changed over to my 2 1/4" hose and now there is plenty of suction. I am using the original one inch dust collector so if you don’t want to go with the bigger dust collector chute, it is doable. By the way, my vacuum is a Harbor Freight dust collector. I modified it so it never loses suction but that is for a different forum.

I love the big window on top of the dust collector. I can see everything.

I took a closeup picture of the ring and the router clamp. I noticed during my test that the rollers are getting pretty close the the clamp. It may become an issue that when/if the sled goes to the extreme ends of the table, it may get interference from the clamps. If it becomes a problem, I may need to re-make the clamps thinner.

I realize no-one is likely to buy a 3D printer just to make this setup so it may be an opportunity for you, Bar, and Hannah to offer these parts for sale on their website. This is a great “aftermarket” setup for a great vertical CNC machine. You could even offer templates or files that can be used to cut out the wood parts using a scroll saw or band saw as an option.

You put a lot of work into this and should be proud. Everyone should be able to build this and a Maslow CNC whether they have a 3D printer or not.

Just my humble opinion.


#116

Update…
Success!! Nice and clean. Here is a video. And Thank you for all your help.


#117

Ok my sold… Ordered some parts… :slight_smile:


#118

@huntleybill thanks for the video! Seeing it in action is amazing.

@MeticulousMaynard thanks for your hard work on this and especially for sharing!


#119

That’s awesome. Can you show a video of the z axis moving a significant distance?

Also, with the very enclosed dust area, are you noticing any tendance for it to vacuum suck the sled to the cutting surface and increasing friction there?


#120

I do not have a video of the Z axis moving the full range but it does move smoothly and fully. The only thing you need to be aware of is the router bottoming out on top of the dust shield

As for the suction, there is no issue with it being sucked onto to stock surface as there is not that much suction. Also, with the hole that the router passes through in the dust shield, that possibility is eliminated.

What did surprise me was that the 18 pound sled, without any added weight, moved smoothly across the plywood and cut with no issues. At this point, I am not going to add weight unless I need to.