Breaking bits on MDO

ernie

New Member
My new router is so much faster that I have been breaking bits. Of course sign foam is no problem, but cutting out 3/4" MDO has been causing my carbide bits to break.

What speeds and feeds works best for you? Does anyone have a favorite cutter design for MDO?

ernie
 

dccas

New Member
I just use bevel or round overs on my mdo signs,
many times I'll make a couple of passes..

the faces don't necessarly chip, but sometimes the
inner laminates chip, can't help that, I then treat it
as a void and spackle, sand, prime, re-peat
 

ernie

New Member
Mike,

I've been using ENCO solid carbide double edge spiral upcut bits. I make 1/4" deep passes while cutting the outline of MDO. The bits are sharp and not burning the wood. After a 10 or 15' they snap. On my old router I would always use 1/8 bits now I'm even breaking 1/4" bits.

I can do ok at 25" per min. but I would like to run a little faster.

ernie
 

Alf D

New Member
I don't think you can have it both ways, you either need to slow the travel speed or the depth of the cut.
I prefer to cut fast but at a shallow depth and do multiple passes.
 

Mike

New Member
Ernie,
Have you tried a 2-Flute wood rout up spiral or a 2-Flute compression bit . I use them both and they work well. Compression bits keep it from chipping on the front and back.These bits I run 1/2" deep and i start at 100 ipm
 

ernie

New Member
Mike,
The Rosberg MDO seems to be much harder than it used to be.
What brand bit are you using ? The Enco bits are designed for metal cutting but they have always worked well in the past and they cost about 1/3 of wood router bits.

I will buy more expensive bits if they will hold up better.

ernie
 

Mike

New Member
ernie,
I have a supplier in town that makes some nice bits for me.
You might want to try onsrud they also make some really nice bits
 

Dennis Raap

New Member
Ernie,
I have not done much routing with MDO yet but I have routed 3/4 plywood set the machine at 19,000 rpm and 300 inch/min 1/4" per pass didn't have any problems. Using Gerber bits just because I got a quite a few when I bought the router 1/4" bit two flute spiral. You should be able to run a quite a bit faster I would think. :signs101:
 

ernie

New Member
I'll have to look into Gerber bits, I bought some for V-cutting but I never tried their end mills. With feed rates of 300 ipm they must be good.

ernie
 

Mike

New Member
ernie,
Gerber Gold bits are not worth the money. they charge way to much for a simple Tin coated bit. And dennis why are you only going a 1/4" down
 

Dennis Raap

New Member
Mike, I have not routed much MDO or plywood wasn't real sure on what I should use for settings on the plywood had to route 20 sheets for a guy. Some people told me they run more passes faster I don't know still learning. I have some other bits to try when the Gerber ones are used up like I mentioned I got a quite a few bits when I got the router.

Ernie, just a thought is the feed on the router actually feeding at the 25 ipm that you have set or could it be feeding faster for some reason?
 

ernie

New Member
Dennis,
My old router would hesitate with everyblock so it never achieved the set speed. It would max out and high rates were only achieved with single large moves. Smaller moves really slows it down.

The new one looks ahead 10,000 blocks so it never slows down. It flys along at the rated ipm.

Talking to the Onsrud tech guy, it may be the way the Porter Cable collet supports the bit. All the bits are breaking up near the collet.

I'm ordering a variety bits to see what works best.


ernie
 

Dennis Raap

New Member
Ernie, that is what I was wondering if you were moving at 25 ipm or if you were actually moving faster have you timed it to see if it is accurate?
Onsrud are the bits that I was going to try when the Gerber bits are gone let me know how you make out.
 

ernie

New Member
I guess I'll have to do some machine timings. But I believe the practical cnc router is accurate.

ernie
 

openwood

New Member
I am joining the thread late but I will tell you how i cut mdo.
I use a 1/8 or 1/4 up cut sprial bit. with a 150 ipm feed rate and a 80 imp plunge.I also only use 1/4 depth per pass.I have found that Routers and cncs using these small bits definitly have limits.I have broke alot of bits trying to speed up the project and ended up having it taking longer because of broken bits.most of the cnc operators that I talk to have true cncs and bit shaft dia. start at 3/8 and go all the way to 3/4".
I will admit bit quality does make a differance.
I have had ok luck with gerber bits with slow feed rates.
I mostly use frued bits.The entire bit must be solid carbide,it cost a little more but is well worth it.
I also got a feed rate chart when i puchased the table that gives feed rates for various materials.I will try to dig it up tomorrow.
I also sometimes go into the templates in artpath to get feed rates for certain materials.
Brian

my house remodel is almost complete,I look forward to returning to the site on a regular basis again.:signs101:
 

ernie

New Member
The new onsrud bits are here. They seem a lot sharper than the Enco metal cutting endmils. I bet they will cut MDO like butter.

ernie
 

ernie

New Member
I got 3 bits to try, all 1/4"
48-106 carbide tipped 2 edge straight cut.
56-285 solid carbide 2 edge straight cut.
52-285 solid carbide 2 edge spiral upcut.

I only went for the $20 bits, I'd feel really stupid if I bought a $50 bit and then broke it after a couple of cuts.

ernie
 
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