Woodworking Talk banner

1 - 12 of 12 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
I build model rockets and am moving up to fins that are 1/4" ply. I'd like to round the edges nicely and was thinking of using an 1/8" roundoff router bit but have realized that this wouldn't work so well because the spacing between the cutter and the bearing allows the ply to slip in too far (sometimes even on the first side).

Only 4 fins and they're only 4"x5" but I'd prefer not to have to hand sand them to shape. Any thoughts welcome.

Thanks, Dave
 

·
John
Joined
·
3,028 Posts
I build model rockets and am moving up to fins that are 1/4" ply. I'd like to round the edges nicely and was thinking of using an 1/8" roundoff router bit but have realized that this wouldn't work so well because the spacing between the cutter and the bearing allows the ply to slip in too far (sometimes even on the first side).

Only 4 fins and they're only 4"x5" but I'd prefer not to have to hand sand them to shape. Any thoughts welcome.

Thanks, Dave
I'd use a bullnose bit like this one:
http://www.ebay.com/itm/Bullnose-Ro...868082640?pt=Routers_Bits&hash=item565975d7d0

Double face tape a template of the shape you want (I'd use 1/2" MDF for that) to the top of your wing for the bearing to ride on. The first pass will cut away enough of the template for subsequent use.
Because 1/4" ply probably isn't 1/4" a 1/8" round over will corrupt the guide edge for the bearing and the round over will be off center.

4x5 is pretty good size, especially for a rocket fin. I'll bet that one uses some BIG motors:laughing:.
 

·
Registered
Joined
·
423 Posts
They're elliptical, not square. Thanks.
Tour welcome but it will still work with a curved shape I have done the same thing with a curved piece you just have to set the fence in the correct spot. The bullnose ideas would work well too I just don't have a bull nose bit.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #11 ·
Tour welcome but it will still work with a curved shape I have done the same thing with a curved piece you just have to set the fence in the correct spot. The bullnose ideas would work well too I just don't have a bull nose bit.
OK, After reading Phaedrus' response I see what you mean. I'll give that a try after I return from vacation :cool: Thanks to all.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #12 ·
So when I returned from vacation my 1/4" bullnose router bit was in the mail. Cut a template and trimmed it to the same size as the fins. Pinned each fin in turn to the template and ran it around the router bit. Not counting making the template it probably took all of 15 minutes and that was because I'd never done this before.

I now know that for the next time I need to pin the fins and template then cut the template at the same time as the fins. Works a charm.

Thanks for all your help.
 
1 - 12 of 12 Posts
Top