Nema23 mounts

I’ve got these motor mounts from rattmmotor88 ebay seller for just $15.67 each one, shipping and hex screws included. Shipping was really fast (fedex), just eight days (I use to wait 30 to 50 days for items from china).

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Packaging could be better; there are some scratches, but nothing you can’t fix with a file. Internal milling is great. External sanding finishing looks nice, but flatness is somewhat compromised; milling finishing for mounting surfaces would have been great. I don’t understand why they make motor recess 42mm diameter when it should be 38mm; anyway this is not a serious issue. Of course a critical parameter in these mounts is the space they add between motor and mount surface; 40mm in this case.

As this kind of mount allows a lot of play between leadscrew axis and motor axis, you should be careful every time you install X or Y motors, especially if you’ve got heavy motors and/or your couplings are “flexible type”.

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CNC6040Z

This gallery contains 16 photos.

Cheap chinese routers: will be worth? That’s the question (or was, for me). So here’s my new machine; well, just a frame. US $1040, shipping included. Here’s the link. I’d rather choose this machine instead the most popular chinese router … Continue reading

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Things you don’t know you need

I’m quite tidy. But when I’m working, I should move from my chair to get any tool. So every tool I grasp ends on my table (because I’m too lazy to put it back), and after some days my work area turns into a mess, so later I should spend a lot of time putting everything in its place. But now I have this:

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This is a really cool tool organizer: compact, cute, wheeled. Having your tools at hand, fast and easily, makes a difference. I’m in no way associated with Keter, and for sure there’re another brands similar products, but this is a great product.

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Learning the hard way

When I was a CNC girl, I thought things like “Once you make one, you can do thousands, easily!”, “Acetal is the perfect plastic for precision parts and cuts like butter!”. OMG I was so naive. Making these parts were really a pain in the ass. That’s why.

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Acetal has internal stresses. This mean that if you remove a significant mass from a block of acetal, the final shape will warp a bit. I knew that. But what I didn’t know was that sometimes this natural “stress relief” can take hours. So one day I was turning a lot of these parts, everyone having a perfect bearing fit. But then, on the next day, the bearing fit was really tight; the parts have had shrank a little bit. May be acetal I got wasn’t annealed? Or may be I should anneal these parts? (yes, plastic annealing is a topic).

BTW, in this specific case, a bearing housing should, ideally, not divert more than 5-7um from the nominal size: 10um less and the bearing will not fit; 10um more and the bearing fit will be too loose.

Now the other issue: long aluminum crosslide = noticeable thermal expansion. So the table temperature will change after stepper warm-up. And, it will change again after some machined parts. From what I remember a machined radius can easily divert 0.03um because of thermal expansion. And rehomming after temperature changes can be a bit misleading.

The good thing is that, once you understand these issues, making something to avoid or reduce them is not too hard. The bad is that now I have a full bag of black plastic decoracion parts (not the ones in the pictures, of course).

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There’s a nasty thing in my nose

Have you ever checked your nose?. I did. Three ones. Here’s how it looks just after some retouch (saddly I didn’t take a before pic):

IMG_2653 And here’s a nose from a new spindle (9/16″ through hole version). It’s not just aesthetics… trust me.

IMG_2655Now, if you are happy with your nose, please don’t worry.

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