Rafix 20mm bit w/ flat on shank

[Doug Smith]

Hello folks, first post for me.

Hefele has a drill bit for Rafix fittings. #001.24.327 This bit has a flat on the 10mm shank. This bit also cuts a countersink for the rim of the Rafix . I have a Porter Cable router, and also have a 10mm collet.
1st question - Am I nuts to think about running this at the slowest speed in my router?
2nd question - If this is not so nutty, will the 10mm collet hold (securely) on the 10mm shank with the flat?

Thanks for all input on this,

Doug

[bleeth]

Doug;
Although you can probably use this that way no problem it seems to me that the time changing bits and re zeroing for the rafix holes would be more than just pocketing them out with whatever bit you are using for the rest of the part machining.

[cabnet636]

i have had bits with a flat portion of the shank slip in an er25 collet, i would think contacting onsrud or a bit manufacturer would be a good idea, i am sure someone is doing this with cnc

jim

[wberminio]

I agree with Dave.Just use the same bit that you are using for your profile and add it the file.
You will save time by not changing bits and re-zeroing.

[Gary Campbell]

Doug....
I both agree and disagree with the comments above.. Only those that dont have 10mm collets and a spindle AND have tried cutting that stepped Rafix would think that you could cut it easier with a bit! Cycle time on a drilled hole is 1.5 seconds. To pocket takes over 5 seconds and tears up mortise compression bits.

I use these bits often in this way, with the following caveat: I use a spindle that has the rpm turned down to the recommended rpm. Usually between 3 and 4K rpm. Your router will most likely not go below 10K rpm and will burn both the material and the bit in seconds. There is also a max rpm for the tool, you dont want to exceed it. Since it is a DRILL, I would assume that 3500 is close to the max for 20mm diameter. I have since switched to drilling these at 2800 rpm using my drill mounted on the A and use a 25ips plunge speed. BTW I have had better luck with the Amana bits than those from Hafele, but those were without the step cutter.

[Doug Smith]

Ok folks, I appreciate the responses, and plan to listen to them:)

The files came to me with a 16mm circle for the Rafix, and after querying, I discovered that the reasoning behind this was so that the circle would not overlap the rectangle of the shelf. This allowed for positive placement of the rectangle into a nest/array. It seems that the center could then be picked for a drilling operation, allowing any size bit.

Dave and Erminio;
I plan on putting the circles on a new layer, then increasing the size to 20 mm and run a pocket cut. I was weighing my computer time vs. bit change time.

Jim;
Thanks for the heads up concerning slippage. Words to the wise!

thanks,

Doug

[Doug Smith]

Gary,

I appreciate your thoughts. The router speed, (your right - 10k) using a drill bit, was what led me to this question. I hate to be nuts.

I will look at the Amana 20mm bit. I will have to do without the countersink for the rim, irregardless of method used. With just one Z axis, and a PC 7518 router, I am thinking that the pocket will be my ticket.

thanks for all the good comments,

Doug

[widgetworks_unlimited]

I'm all for trying new things and I don't like to be negative about ideas when I don't have experience to share, but this sounds extremely dangerous.

I've seen a 1/2 shank bit come out of a collet at 20k rpm before - didn't have enough shank length inserted to hold it in place. Very scary! Luckily the bit was in mid cut when it let loose. Also lucky that no one was nearby at the time.

If the job will pay for adding an air drill, I like Gary's setup. If not, I'd take the time to go with the pocketing.

[bleeth]

Russ:
You don't have to do without the counterbore if you don't want to. It is simply a shallower pocket.