Router bit selection......

[fairchild]

Got my master rib form made and the holes bushed with steel bushings. Ready to copy/route the working copy of it. Thinking about router bits.
Have a 1/2 by 1/2 copy bit. I need a bit with at least a 1 inch cutter. I see rockler and woodcraft both have 3/8 dia cutter and 1 inch long bearing copy bit.
i would rather have a 1/4 inch dia. cutter but those are like 115$ ------ that just seems a stupid price. The 3/8 is like 18$. I know that the smaller the diammeter
the bit the less tendency to grab the work and run off with it.....

I have my router in a nice heavy router table. i will be bolting the pattern and the blank together with a 1/4 inch sheet to keep the boltheads off the table.
(keeping a nice flat , square surface on the tabletop.) Is there a secret source for 1/4 inch bits ? (that aernt an arm and a let $ )

Tim

[BTAZ]

IIRC, I used countersunk head 10-32 screws installed from the bottom template up through the blanks and through the top template to keep a flat surface for the bottom template to slide against the router table. That would eliminate the extra 1/4" you are describing.

I just used a "typical" 1/2" router bit/bearing from Home Depot(was around $15) for all my aluminum routing. I'm sure there are some more expensive bits that might work a bit better but there is also a time to "Just do it!".

[Chewie]

For giggles...

https://www.google.com/search?q=router+bit+site%3Abearhawkforums.com&ie=utf-8&oe=utf-8

[S Lathrop]

I believe that a 3/8 2 flute carbide router bit is the smallest you can get at Home Depot. That is what I used and I used a hand router to cut all my wing rids.

I did not use a router table. I did mount the rib patterns down to a table.

I used 3/16 dowel pins to align the rib blanks with the cutting patterns and the forming blocks. When I cut the ribs with the router, I had a piece of thin plywood covering the aluminum blanks. I cut my ribs 3 at a time.

What I found to be very important is to always use a climbing cut when I cut the aluminum. A climbing cut pulls the cutter into the work and gives a better finish. A climbing cut is clockwise when you are cutting the outside of a part and counter clock wise on an inside cut such as a hole.

[sjt]

Whiteside Router Bits RFT5125 1/2-Inch Diameter Spiral Flush Trim Up Cut with 1-1/4-Inch Cutting Length

I used the above bit for all mdf and aluminum. I believe that the router will get away from you when you try to cut more then the radius of the bit. It is best to trim aluminum to within 1/4 or it will grab.

I think the Up cut means it pulls into router. To me this is preferable if you take the precaution of using a vacuum and sealing up any where the aluminum will get into router. The aluminum flys everywhere even if you use an upcut bit.
Also, the aluminum shavings are hot.


A down cut bit will spit hot aluminum away from router -- ie towards you-- it will also push work piece away making it harder to control

I also bought a Whiteside Router Bits RFT2100 1/4-Inch Diameter Spiral Flush Trim Up Cut
I used it for making some of the aileron nose ribs