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Making radius discs

Posted: Thu Dec 18, 2014 10:02 am
by Phil
Do any of you make your own radius dishes? I am thinking of giving it a try and just wondering if anyone has any tips regarding this process. Machining something like MDF = lots of dust so I have already thought of dust mask and using my dust collector! Any other tips?

Re: Making radius discs

Posted: Thu Dec 18, 2014 11:10 am
by tippie53
do it outside in the middle of a tornado ,
Yes dust collection is the serious side if you don't have a cnc you want to research the long compass method.

Re: Making radius discs

Posted: Thu Dec 18, 2014 2:03 pm
by Phil
Long compass method? Yeah I'll have to google that later since I have no idea what that is. I was looking at a few youtube vids this morning showing using rails and a router to cut the dishes. I have plexi glass radius gauges for the 2 radii I want, thought I could make the rails using the radius gauges and a pattern router bit. Maybe I'm over simplifying the process of making the rails?

Re: Making radius discs

Posted: Thu Dec 18, 2014 7:03 pm
by tippie53
This is a good way to do it, the long compass method.


Re: Making radius discs

Posted: Thu Dec 18, 2014 9:09 pm
by Phil
Wow that's quite the jig he has for making dishes! It looks like it would give one a lot more control then just a couple rails and a router sled.

Originally I was thinking I might be able to save money making dishes myself but maybe its not worth trying to do it myself for just 2 dishes.

Re: Making radius discs

Posted: Thu Dec 18, 2014 10:31 pm
by  
Phil wrote:Originally I was thinking I might be able to save money making dishes myself but maybe its not worth trying to do it myself for just 2 dishes.
Better to come to that conclusion now rather than when you're in the middle of the first disk and knee deep in dust.

Re: Making radius discs

Posted: Tue Feb 03, 2015 1:54 am
by Stray Feathers
I asked lots of questions here about this, and read lots, and used lots of the suggestions (sorry, I can't recall whom to thank specifically, but you're out there . . .) I took a longish detour and made this jig up and used it to successfully make a nice 28' radius dish. I plotted the radius using a a long tape measure, squaring a pattern with two corners equidistant from the centre of the radius, then cut a concave piece, and sanded it fair it by flipping it end for end and tracing the pattern, again and again, until both ends matched. Then I cut a convex pattern from that and faired it, same way. From that I cut two rails for the jig, and sanded them using a long strip of sandpaper on the convex pattern. I had to do some minor tweaking when I put the rails into the box. There is a 1/4" dowel in the centre, and a 17/64"" hole in the dish so it spins nicely. I had to remove one handle from my father's 1970s Craftsman router to slide it far enough back to shape the dish to the edges of the octagon (which gives it something to hold on to when rotating it.) It's time-consuming but saves some dollars (which, on this side of the border, buy less every day . . .) I have a +/- 15' radius work board for the back, made by a friend, but I like my new one so much I may make a 15' version too. I can easily replace the 28' rails by removing a few screws. And yes, ear and eye protection, a dust mask and dust collection system too.
router sled 2.jpg
router sled 1.jpg

Re: Making radius discs

Posted: Mon Mar 23, 2015 5:23 pm
by Kevin Sjostrand
No pictures of the process, but I made a jig for the router and made me a back to back radius dish on Saturday. Glued up two 3/4" pieces of MDF 24" round. IT worked out quite well. I still have some bit marks to sand out but I'm happy with the results. 15' on one side and 30' on the other.
Ordered the paper for it today.

Kevin

Re: Making radius discs

Posted: Mon Mar 23, 2015 6:24 pm
by Tom West