View Full Version : What's this Carbide coating.

10-11-2014, 08:46 AM
I have been looking for the best router bits for shaping polystyrene for a long while however I still yet to find a good solution that is not crazy priced. The best I have found so far is these burrs from the USA at $40 each and which are supposedly carbide coated however it would be great if they were a bit longer.There is one but in the USA also I have found but runs in at $600 each !

I have been looking every were to try and find out ho they do the spiky carbide coating but with no luck so as to possibly look into having something custom made possibly how ever no idea of cost or if it is even posable.

as it is only for cutting foam would it be posable to have some made with the spikes just in steel and then heat treated? I have no real idea but just looking for options other wise it will have to be a long flute to do a ruff out and change for a final pass with a burr.

10-11-2014, 08:50 AM
Any use ?


10-11-2014, 11:59 AM
Unfortunately not I'm looking for exactly the same as my picture just with the cutting depth to be about 3 inches rather than 1.5

10-11-2014, 12:39 PM
This seems to be the manufacturer http://www.saburr-tooth.com/index.htm can't seem to find any info on longer shanks on their site though. Do you need the whole burr to be 3 inches or just the shank? If you're happy with a longer shank perhaps you can have an adapter made, to give the effect of a longer shank, to fit your spindle

10-11-2014, 01:37 PM
Yes those are the ones I got, a longer shank would be a start but ideally the cutting edge wants to be longer . Many thanks

10-11-2014, 05:12 PM
What you are looking for is called a rotary rasp.

Boyan Silyavski
10-11-2014, 05:23 PM
Thats definetely non stick teflon coating, similar to Freud .

Now i i don't have something clear. Why use burs instead of some ultra sharp sharp micro grain carbide router bit, say 3 flute straight long reach?

I don't see how you will route faster with these compared to normal router bit. Also if you insist on burrr just buy roughing bits.

What size bit, depth of cut, speed and step over? lets do the calc here. cause i dont see it right using these bits on foam.

10-11-2014, 08:22 PM
there's these ones from France....http://www.hand-stitched-rasp-riffler.com/rape-rotative-diametre-25-mm.html

Or this, I know it's only a ball but it's 30mm diameter? http://www.clasohlson.com/uk/Rotary-Rasp/30-9512

10-11-2014, 09:30 PM
The burr style is a prity standard practice when working on surfboards. From experience I have had in the past normal fluted bits can tend to heat up after a long duration and coolant is not a option and on eps this can end up melting the foam which can make a right mess. The burrs also give a great surface Finnish.

im open to ideas ?

I played with the two burrs I have today and even the fine one seams good.

No idea how hard or I fit would be posable but would it be posable to make a blank bit on a lathe and then coat it in some sort of abrasive grit? I'm assuming balancing would be the major problem?

Boyan Silyavski
10-11-2014, 10:13 PM
i would give you tons of ideas but you have to give me some data to work with :monkey:

What size burr, depth of cut, speed and step over you use now? Do you pocket or slot cut? What is your collet size ? Spindle kw and rpm? What speeds your machine is capable of? What rails and ballscrew ?

11-11-2014, 11:28 AM
The two burrs I have are 33mm cutting depth and 21dia 64mm overall The ideal would be something around 25mm dia 75-90 mm cutting depth 130mm over all
I have a 2.2kw water cooled huanyang spindle so er20 collet so 13mm max using hywin 20 rails x is on mod 1 rack geared 3.2-1 rapid is set at 10,000 mm/min but capable of a lot more but to scared to set higher at the moment. y and z are 1610 ball screw set at 2500mm min and it is quite happy cutting at 2500mm/min. When cutting a surfboard it is basically just running up and down the length with very small y and z movements most of the time

Boyan Silyavski
13-11-2014, 02:10 AM
I remember somebody using plan drill bits for the purpose. A good bit like Dormer is quite balanced. Leave, flatten or ball nose the face. But a proper reamer I belive is what will do the job.
As you can see bellow more or less the special foam cutters look similar.

so why not just buy proper foam cutter or try some of what I suggest for a diy solution

Look at this baby

13-11-2014, 08:52 AM
The frog tools are pretty expensive at nearly $300 dollars befor shipping and tax and the other is only a max of 1/2" dia so a little on the small side ideally but maybe a possibility if I can't find anything else

many thanks

13-11-2014, 08:58 AM
How big is your max size collet on the spindle?

13-11-2014, 09:20 AM
It's a er20 collet so 13 mm

many thanks

13-11-2014, 11:15 AM
http://www.copycarver.com/images/Saburr%20Tooth%20General%20Burr%20Set.jpgI found this picture so it looks like it is some sort of coating that they put on.

Boyan Silyavski
13-11-2014, 01:00 PM
There is no free lunch this size. You want fast, means you are making .
Now you wouldn't like cheap not perfectly balanced tool this size on your spindle.

Your best bet is custom tool, should be cheaper than what they want. Later can be re sharpened many times so that's even better money wise.
But as you see the burrs are not the proper tool, even if they work fine.

13-11-2014, 05:32 PM

Here is a thread I started when I was looking for a simlier tool. I also looked into the frog tools but the cost was too high when I was unsure if I even had the ability to mill the foam parts I needed. After completing the job I would say that the vast amount of running time is actually in the final finishing passes and the rough cuts take very little time in comparision. I don't know what sort of finish and step over res you are going to use but I would suggest starting out with some cheap tools to get a feel for what you need to complete the job in an acceptable time.

I bought some cheap indexable insert mills and also some pricey ballnosed mills but half way through the job I relised I could use the endmill to 3d profile and rough the part so the ballmill became redundant. Condsidering the ball mill was twice the price of the endmill it was a costly mistake.

I also think you spindle and machine may not be man enough to take a large frog tool but I could be wrong. I just know even on my thermwood the larger tools cause a hell of a lot of vibration due to off balance tools and jerky machine movement. Burrs dont look like the most balanced tools available with all that carbide glued onto a blank at random angles.

13-11-2014, 06:13 PM
Cheers many thanks I took a look at the thread. The burrs I have seam pretty well balanced there's certainly no noticeable vibrations and cut well at around 6-7000rpm I think the way to start is going to be getting a collet extender which luckily come in er 20 1/2" and relatively cheap and will allow me to use the burrs I have all be it having to do a few more passes and get me going then try a few other cheaper bits and and hopefully in the mean time save up for something a bit more specific when I know what works best.

14-11-2014, 11:38 AM
I have been playing with a variety of end mills slot bits and standard router bits and the pics are bellow. It seams unless you run at very slow feed rates you get a large amount of tear out with any of the conventional bits and that was with a variety of feeds and speeds.however with the burrs the spindle speed could be significantly lower and feed rate a lot higher and still giving a very clean cut with minimal tear out which is why I have been trying to persue them.

Boyan Silyavski
16-11-2014, 11:27 PM
Truth is I am not s specialist concerning foam. I cut only once before a couple of weeks when I was demonstrating some 3 d job setting to my friend on the yellow machine I made for him.
So without knowing anything I started at 4500mm/min with 3 flute straight 6mm carbide bit. The cut was perfect. Spindle was 16000rpm. I pushed it somewhere to 8000 mm/min where was still acceptable the finish.
Now I have to tell you that the machine is extremely sturdy. I suppose that with the proper bits for foam , some air stream at the bit, 10000 mm/min will be no problem at all . And this cheap construction foam.
what I want to say that the bits you use must be good, SHARP, and the not sturdy frame and z can and will play you tricks there, so take it slow and concentrate on making back some cash.

But it would be interesting to hear what speeds and feeds others and you are cutting foam at?
I'm very interested in this discussion cause one of the things I would do on the big machine I am making right now will be molds from foam. Not to speak of the paddle board I have a plan to make and some other stuff. Plus foam is nice for casting aluminum, molds or directly