Acrylic Cutting Tips

Jon thanks for the explanation… I checked with the local plastic shop in my area and the price for cast is going to prevent me from using it… they want $305.00 for a 4x8 sheet of 1/2" and do not sell in smaller dimension.

I am working on a dust shoe now and I hope that will help. However, maybe my spindle is just not suitable for this. It is a 500w spindle off of amazon and I think the max rpm is 12k.

I was trying to do a very light engrave on 1/4" and as you can see the results. I tried a different bit last night which does not give me the same results as the fine tip bit but I didn’t have anything get melted. It was an amana tool 46282 Ball Nose (Conical Ball) Solid Carbide Spiral CNC 2D/3D Carving . Probably not the right bit but everything I have tried ends up melting. The top line is with the 1/8" 30 degree bit but if I am not right there blowing compressed air it melts.
The lower line is with the Amana Tool Ball Nose bit. I prefer the top but cannot seem to find the right combination of bits, settings, etc. I’ll try again after I get my dust shoe mounted but I am not sure that will make a difference.

Hi, it’s a shame they can’t cut to the size you need. $305 for 1/2" sheet 4x8 (feet I assume) is pricey. A piece the same thickness and size would cost me $240, and I know the quality to be excellent, having purchased more than a few pieces from the supplier in the past. Of course I only order pieces of a maximum 750mm x750mm (30.5" x 30.5") to fir comfortably on the x-carve.

Amazon have smaller pieces available but you could also try scavenging. I have become quite expert at finding good material others consider waste, and the skip behind a local sign making firm has been a treasure trove of useful stuff. I also visit local recycling yards when I get a chance. It’s amazing what people throw away when they can’t see value in it. Even if it’s not good enough for a finished piece of work you can practice on it without worrying about the cost. Shorly after building my x-carve I was lucky enough to find two pieces of 10mm thick acrylic, each 2000mm x 300mm (78" x 12") in a skip behind my office, one tinted blue and the other tinted red. I butchered most of it but learned a lot in the process, not least of which was to use scrap material for test carves until I was confident I had everything setup correctly.

My mill end of choice is a 3.175mm (3/8") two flute upcut. I have a DeWalt spindle and run it a max rpm for pretty much everything. @PhilJohnson mentioned it earlier in the post, you do need good airflow when cutting acrylic. Mine comes in two shapes. Firstly I have a diffuser to redirect the downdraft from the DeWalt, which circulates air inside the dust shoe (and not directly downward, which was causing spoil to escape from the sides) and secondly generated by the shop-vac connected to the KentCNC dust shoe.

Good luck with the dust shoe, and post an update to let us know how you’re getting on.

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Jon - what model dewalt and can you post a pic of your set up? I also have a DW660 but it’s so loud.

Hi, I have a DeWalt D26200, of DeWalt 611 in the US (same model apart from the how the cable exits the motor housing, as far as I can tell). It’s loud but has plenty of grunt, so I wear decent hearing protection. Maybe next year I’ll look into a water cooled spindle but I don’t run the machine too regularly so can live with a little noise for now.

My dust collection setup has evolved with experience. Here’s a short video clips:


Another angle:

Here is a link to some pictures of the diffuser I made for the bottom of the DeWalt spindle

Wow that machine is very nice… this is the shoe I worked on today… not sure how well it will work.

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Cheers, I am slightly obsessed with my x-carve. The dust shoe design looks great, and the color is spot-on (by my tastes). I must sort out a 3d printer one of these days!

How long did the part take to print?

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That shoe was already modeled in Thingiverse but I had to tweak it for my MPCNC/Spindle set up. I think all in all between the shoe and the brackets about 8 hours total. I have two 3d printers so half that. I got it mounted this evening and have cut two larger acrylic sheets and it did well - meaning there is very little shavings left -
I am using a shop vac so it’s very noisy.

Here is the cut from tonight - Took a little over an hour to cut this.

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Here is the dust shoe I am using. I think with the top part being really opened I have some debris coming out so I may have to model it with a smaller hole.

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I’d recommend cutting a plate and tacking it in place to test before printing another part. If you cut it from clear material it would act nicely as a window, allowing visibility of the cut.

Yes, that is a good idea .

One other question you guys may know about working with acrylic… given I am not using cast acrylic after you cut it how do you get the edges clear or is that not possible?

I thought I seen somewhere if you use a torch with with Map you can get the edges clear again but not sure if that is true and how “easy” it really is if possible.

Yes you can flame polish the edges, though it takes a little practice. What you’re basically doing is attempting to melt the top surface, but be careful not to burn it. Take your time and keep the flame moving at a consistent distance from the edge, much like you would if you were spray painting. I’ve also used emery paper and then acrylic polishing compounds and a small buffer.

Has anyone tried any of the other Onsrud bits? $100 bucks is bit steep for someone not cranking it out in volume, but I see they have smaller diameter bits in the $30 range.

There seem to be about 5-8 different bits that all look basically the same.

I’m considering the 63-602 mainly as a profile cut-out bit. (which is where i have all my problems with acrylic)


I use the 63-515 with great success and if you contact your onsrud local dealer, you can get better pricing if you have a business license. I pay around $20 per bit

I’m wondering if any of this info will help the Carvey?

Do I keep the plunge rate the same as the default settings on Easel?

Single flute spiral up cut bit and faster movements.

If you’re still looking into bits, just look on amazon for decent prices. Onsrud bits should be in the $25-40 range. I’ve been using Amana “spektra” bits recently, and they give a slightly better finish than my Onsrud bits. They have a few options but I haven’t looked into much other than the 1/4" and 1/8" spektra coated ones. They are a bit more expensive than the Onsrud bits too.

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Looks great! What type of acrylic did you use here?