Seeking Advice

Hey guys, I’m in search of advice. I’ve been hired by a University to make some signs for them. They have seen some of my work and sought me out for there for my work…

OK, just kidding. I actually work for The University. I did However make a rendition of their old Seal with an updated name. (They changed from “College” to “University”)

My question is… They are asking me to make some signs for the Dorms. They have bought some 2" 20# Precision Board HDU. I have ordered Coastal’s recommended bit ( LMT ONSRUD .25" Carbide Double Flute Upcut Spiral O Flute) When I watch their videos, They are running fast, (like 360 IPM). Ive heard this stuff cuts like Butter, But even when I cut foam, My rear is puckering at 90 IPM.
So Being the stuff does cut easy. In regards to Bit life, will it hurt the bit to cut it at .25 DPP at 90 IPM? What would all you X Carve Masters cut it at? I plan to pocket letters and picture. Prime with FSC-88WB and Paint with some Sherwin-Williams Exterior paint. Ohh did I mention the signs will be 2’ x 7’.

OK, Sorry about all the rambling. Here’s what I will be carving.

Any suggestions? Thanks in advance :slight_smile:

Can you do a test with a small piece?
I’d go as fast as you can. The material shouldn’t slow you down, and you don’t want to make dust.

Will your x-carve handle moving at 150in/min? 200? Without material. You could run an aircut and see if you lose any steps.

I’ll give it a try. just worried about breaking something.

The only thing you could really break would be a homing switch off you crash into it.
If you’re confident in your ability to run the machine without crashing into those switches, let it fly. Like I said, if you lose steps, you’ll lose position and you can’t go that fast. Your machine is limited in speed by the grbl settings and it moves at those rapids frequently.

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If I try and don’t lose any steps, How fast do you think I should I try to be at?

I have cut HDU a few times on the X Carve and it has cut great. Those 2’ X 7" panels will be over 40 lbs each so use caution when installing them. I started at 80 ipm and increased it from there, I cut .25 deep per pass.

Well @NeilFerreri1, I just did Air Carve at 150 IPM with no change to X or Y ZERO. Then Changed to 200 IPM, NO CHANGE. Should I push any more than that? @RussellCrawford,


I’ve never tried that fast, I though 120 was fast. Try cutting a piece and see how it looks. I will stick a piece of HDU on and see how fast I can get it to cut. I will take a picture and post when I’m done.

Thanks @RussellCrawford,

I’m Having a hard time wrapping my head around the idea that something that weights this much can be cut this easily. Whew, I need some BEER !!

I cut some HDU, I was cutting .5 inches deep per pass and 225 ipm. The straight cuts cut great, the small curves on the number 3 and 5 had a little chatter. The machine wasn’t under a strain at all.

My first post to YouTube, it was pretty easy.

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Like I said earlier, let it fly!
I’ll defer to @RussellCrawford on this as I have different machines.
Get a video!

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Thank you Guys !!! @RussellCrawford and @NeilFerreri1. My plans were to just V Carve these two signs with larger area clearance .25 inch bit. Then I thought maybe Raised letter toolpath. All professional signs I see have raised letters.

They had one made which is just flat, so either way I will probably stay at either .25 or.125 total depth.

What is your guys opinion? Or should i just do straight pocket with End mills?
Here is my File,HOFFHEIMER Hall Embossed.crv (6.4 MB)

Thank you in advance.

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My advice is to find the sweet spot for every cutting bit that you will use on this material. It could be super fast or it could be super slow. Running a cutting tool too slow can reduce the life of the tool and provide poor results, running the tool too fast can provide poor results as well. That’s why you need to run test to determine what the best feeds and speeds are for cutting the material, what D.O.C. works best with the sweet spot etc and document this information for later use.