Reply To: Oval holes

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Thanks for the quick replay. It is good to know that it is not normal. 🙂

I sourced the parts my self. I live in Denmark. If there were an European reseller, and maybe a metric version, I would defiantly have considered buying a set. I am using a Smoothieboard to control the machine. I have some experience building 3d printes, but I have very little CNC experience. I have added a few more images of my machine.

From what your shown, I could say maybe belts are loose.

That was the first thing I checked. The belts are quite tight, not like on a Guitar, but almost.

or maybe that vac hose is pulling on your gantry. Attaching a vacuum can add a ton of drag and it looks like you have the rigid part of it still on there, it works just like a wrench extension. pulling even harder on your tool.

Yes. I will try again without the vacuum hose. I think I have done that, but I will try again to be sure.

On top of that you are using a very large tool. What kind of bit are you using, an actual end mill or a router bit? 1 flute or 2, up or down cut or flat, what approx RPM?

Yes. The Dewalt D26200 is quite large (I think it the EU version of the 661), I initially tried with a Dremel, but that seemed too weak. I could hear it loosing speed. I am running the Dewalt D26200 on max, that is 27000 rpm. It can go down to 16000 rpm. Should I do that?

What kind of bit are you using, an actual end mill or a router bit? 1 flute or 2, up or down cut or flat, what approx RPM?

The bit that seems to work the best for me is this: ebay 1mm. What type of bit is the best to start out with?

You speed is really far off did you type it correct? Watch some of my vids 50mm/min is about .8mm/s I cut at about 5mm deep 10k rpm, 15mm/s for ply.

Yes. I did cut with 50mm/min. It is very slow. I wanted to try out slow, to eliminate speed issues. (The speed was an issue when I used the Dremel). I have tried with 200mm/min (3mm/s) with the Dewalt, and it is the same result. As I said I am quite new to CNC, and do not really know what is reasonable.

Do test cuts in foam then pine, foam adds almost zero cutting drag so if you have issues you know it isn’t the material causing them, pine will give better accruacy, plywood sucks to cut for a bunch of reasons.

I do not have any foam, and I am not exactly sure what it is. For now I only have plywood and acrylic glass (Plexiglas). I will try to get something else and try that.

Again, thanks.