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Gerber Sabre 408 Help

The Dotted Line

The Dotted Line
Hi there,

As I normally run vinyl and digital graphics, I don't have much experience running a router. However, our company is in a bind, and they have me filling in, for our normal router operator, during this time. I am running a Gerber Sabre 408 using ArtPath from a PC.

Of course I have quite a few questions, but answers to any would be of great help! I've been totally guessing on the speeds, but just hope I'm not running things too SLOWLY.

1/4" Acrylic I've been running at a speed of 40 using a 1/8" bit. Any aluminum I have run, I've run at a speed of 20, only routing a .125" depth, while using a 1/4" bit. Today I broke (2) 1/4" bits while routing some 1/2" aluminum. The bits broke up high just inside the collet. Also I've noticed the chips that are being extracted are quite small (splintery almost) instead of actual chips that I've seen before. Could the coolant mix be a problem? I just read here today that the mixture ratio is about 10 parts water to 1 part coolant. Ugh - a lot to learn, and of course no time to learn it.

Any help is greatly appreciated!

Thank you!

Tony Teveris

New Member
I would hope your not attempting to cut it in one pass ? You can set up the tool path to make the cut in multi passes, maybe 2 or 3.

Also, one of the things the regular operator should be doing is setting up parameters for different tool sizes and materials and saving them as a template, this way when someone new comes along they can pick from the template list.

Another thing I found was that all aluminum materials are not alike. Some softer, some harder and you need the right speeds, spindle and feed to get it correct.


New Member
Hi james!
Its been quite awhile since I used a 408 but here's the parameters that I used to use for aluminum.

Aluminum is pretty tricky to rout. What hardness is it? I have found that 6061-T6 is wayy to hard and I kept breaking nice new gerber bits.
So I tried 5052 and it routed really nice.
Use a 1/4 brand new gerber gold 2 flute bit with a LOC of 3/4 to 1" at 20,000rpm.

Rout in multiple passes of 1/8", keep your plunge rate VERY slow maybe at around 10. You dont want to shock the bit so it has to very slow.

Dont be shy with the coolant and you do want very fine shavings coming off of it. I'd run the feed rate at around 20. But as your routing you should be able to jump it up about 10%.

Hope this helps!



Custom Sign Shop Designer
The router is a not a real easy thing to get the hang of in a short time.Cut speeds like Tony mentioned do vary allot.Our Co. uses 5052 aluminum(1/4") for flat cut letters. According to Gerber the softer material doesn't cut as well.We run the feed rate at 25ipm,21000 rpm and a plunge rate of 30(on 1/4")Make sure, as Tony said no more than a .125 per pass and have BOTH mist coolents running wide open pointed right at the point of impact.Use a spirial bit w/2 flutes, should be solid carbid also.Good luck.

The Dotted Line

The Dotted Line
Tony, Stevo, Larry,

Thank you all so much for the info! I think then, I am on target, just gotta' get the hang of this beast. We are using 5052, and I've never attempted more then .125" per pass. I will try to open up the coolant/air lines and see if that helps. Also, I need to adjust the mixture ratio as I was too heavy on the coolant, too light on the H2O!

We are at the point where we need someone in here to train us and/or run this thing. Until then we'll continue to sub out some of the work, while attempting to bite off a bit at a time.

Thank you all for your help!!!



New Member
Sounds like the router is out of adjustment and is actually going deeper than .125 inch. Thats the max depth for a 1/4 inch bit. The rule of thumb is half the diameter of the bit. Much deeper and you will break bits. As long as it's getting some lubricant it should be ok. It doesn't use it as a coolant, it's a lubricant to keep the hot aluminum from sticking to the bit. You should be able to cut at a speed of 30 to 35 inches per minute. Slower is not always better. If you have a good bit and the speed is right the chips should be pretty good size like pencil shavings not dusty.
another thing that i do on aluminum is to jog through the steps at the machine control panel and drill out all of the entry points prior to routing the job in aluminum. saves me many many router bits, and make sure to follow the rule of thumb you have been given above to make your cut depth 1/2 the diameter of the bit, this is the most common error i see new cnc operators struggling with....and calculating proper feed rates.

as you start to get results that you are satisfied with make sure to write down the material, feed rate, and spindle rpm so that in time you will have a chart and will not have to guesstimate and be able to just blow and go.


New Member
For what it's worth I always work on a pass depth of twice the bit diameter- i.e. a 4mm tool will cut 8mm max in a single pass.

When cutting metals my spindle speeds go down not up- something like 8000rpm is sufficient for cutting aluminium and stainless steel.

Considering the mess and hassle associated with metal cutting on a router I don't bother anymore- laser cut or waterjet is much less hassle and gives much better results IMO.