Making a 28ft radius dish

[@mikepeacock8385]

This is great! I love your ingenuity and practical, natural approach. People who complain should watch someone else... Your dust extractor hose should screw into the router base - it does on my Triton - it is a LH thread and easing the fixing screw half a turn helps too, but remember to tighten it once the hose is in to avoid searching for the screw later (voice of experience!). Best thing is it avoids the need for the adaptor and tape and it will flex MUCH closer to the router. "Henry" hoses fit in my Triton and cheap spares are readily available on Amazon.

[@MurrayDrums]

Great jig! I'm a drum maker and have a few jigs for turning drum shells using a router, but I'm hoping to have a go at building an acoustic guitar soon, so I was trying to figure out how to make the sanding dishes for the top and back! Thanks for sharing your methods! You might want to glue / dowel your piece of MDF onto some softwood battens, with another piece of MDF on the other side, creating a torsion box, which should help to keep both MDF pieces flat while you use the jig.

[@andyhelipilot3528]

Remarkable video series. Stumbled across one now watching all. Brilliant thank you

[@AlbosNoggins]

Such a great video Susie, thanks so much for sharing. The final product is a mighty fine looking dish!

[@SusanGardener]

+Alex Howard I was going to varnish it, but maybe I should paint it so you can't see the scar :-)

[@AlbosNoggins]

Oh no, I'm a firm believer that battle scars should be worn as badges of honour. Besides, everyone loves a scar! :-)

[@petemclinc]

Use a ball nose router bit, it will make a more accurate radius since there is only 1 tangent point on the work piece.

[@orcunguneser8923]

contents, narrating, video editing all great thanks Susan

[@georgescarlett2320]

You're cute, AND funny. You obviously enjoy what you do, and life as well. I laughed at the start of the video, Lol! Cheers Lady!

[@waltersguitars3336]

love all your shows Susan!! nice jig really nice. Try turning the dish clockwise a full turn while the router is on. after each full turn of the dish, move a little in ,until you reach the center.. the whole dish will be complete with very smooth results. thats how i used to do mine and they tuned out great!! and My jig wasent half as nice as yours! try it. keep up the awsome work!!......Craig

[@jasonadams527]

I tried the same thing only I used a 25 ft pendulum. The amount of passes with a 1/2 inch router bit and the mess it made confirmed to me the value of buying my dishes over making them. But nice work on the tooling you are a good tool maker.

[@rickessegern2857]

Wouldn't it be possible to make your router track only half as long and cut the radius of your dish, from centre to edge, instead of the full diameter? This would save material and space?

[@gbspikyfish]

For holding the MDF down flat I wonder if a vacuum table would be useful - just a wide flat box, where the top has holes that will always be under the sheet that's being cut. Stick a vacuum hose in the side and it should hold the board down to the vacuum table surface. With a valve for the vac (or just the sliding valve present in the handle of many home vacuums) that'll release the pressure just enough to spin the sheet ready for the next cut - might even be quicker than removing and replacing the clamps. One other idea would obviously be something to spin the MDF sheet itself (albeit slowly) - as that would greatly speed up the overall process. It's a bit big for a lathe, so some sort of lazy susan (no name pun intended) might work.

[@timsmoot5141]

You've impressed me once again (every video)

[@bjbnz]

G'day from NZ. Just an idea for you to think about. Cut deep wedges that fit between the Jig and the board that should fix the hold down perfectly along the cut line. Great vids really enjoy them, Brian

[@sparkyprojects]

If you fit a couple of arms to each side of the jig, you could load them with weights, the arms would hold down the board, no need to stop to refit the clamps, you could even add some soft wheels to the end of the arms. I was thinking about weightlifting weights as heavy wheels, but they have a plug in one side.

[@scottreeves6932]

Excellent! Plan for the jig? Securing the two pieces of MDF together before carving might limit the warping.

[@trackerbuckmann1627]

I'm wanting to build a jig to cut fretslots so that i can avoid doing neck binding. I just want to mill the slots out. So i need to figure out a very small bit and a decent jig. Have you done something like this?

[@symonf1966]

Great video as always.

[@johnbee1069]

Lovely! Love your video's - thx so much

[@marcelsmeets4162]

Nice vid. Maybe screw the 40 ft dish sheet of MDF up front to the back....makes it more "beefy" and I like Eric Willianms' idea ...4 wheels that push the piece down on 4 corners. Keep up the good work Susie!!

[@waltersguitars3336]

to turn the dish drill a 3/8 dowel in the center of the dish. on a seprate peice of mdf drill a female hole in the center. get 4 small drawer knobs that are domed shaped on the top and place them on the outside of the center dowel so the dish can smoothly turn with no rock and wobbel.

[@SusanGardener]

+cw007 guitar experience shows the dish cups as you rout it, so I'm not sure how accurate it would be rotating the piece while routing. I guess you could laminate a couple of pieces of MDF, which is what I'll probably do after the fact anyway.

[@marcorojas1130]

Hello, great videos! Which other options exist further radius dish?

[@NeverTalkToCops1]

Just buy a CNC milled dish in the radius of your choice for about $100.

[@MrJiminimal]

Susan, Love your channel! Thought you might be interested in a variant of your jig that I made that gives me almost infinitely variable radius options. Instead of cutting the arc into the top of the plywood rails which gives you a single radius (and is hard to get perfect when one is as bad with a bands saw as I am), I took thin strips of aluminum stock the same width as the rails, drilled a hole in the center and mounted them to the top the rails (wide face down) in the middle with a small countersunk screw (which I filled with epoxy so the whole track is flat). Then all I had to do is calculate the rise on the outer edges of the curve (eg .4" at the edge of a 24 inch dish for a 15 ft radius), shim the end of the aluminum strips to the appropriate height and the curvature of the radius is dialed in automatically. I used a hot glue gun to spot fill in extra supports about every inch or so between the aluminum rail and the plywood support because the weight of the router would distort the rails without them. I made some scale print outs of various radius curves in photoshop, printed them out and taped them to supports to verify that the arcs were correct. Pretty much spot on, and any slight variance could be tweaked at the glue support stage. When I'm done with a dish I twist the aluminum rails sideways (since they're only anchored in the middle), and the hot glue pops off fairly easily leaving a flat rail for the next dish. And un-shimmed I have perfectly flat rails that I can use with my router to flatten larger boards. I also realized after the first go around that I only had to shim one side. I sat the dish I was carving on top of another with a pin going through the center so the top dish could spin. The router was strong enough to carve the arc and put some spin on the dish while it was doing so. I guided the router with one hand from the outside to the middle and used my other hand to control the speed of the spinning dish and make sure it didn't pop up off the spindle, Worked like a charm.

[@SusanGardener]

Nice method!

[@butchd18]

good video keep up the good work i like the triton router

[@paul1962uk]

could watch you all day even when you were standing up for yourself with that seminar speach, good on you girl!

[@NMranchhand]

Such fun!

[@PeteHowlett]

Can I recommend that you have a separate dish for each radius? You will save space gluing back to back but will regret not having 2 separate dishes.

[@SusanGardener]

+Pete Howlett That confirms a suspicion I had. Thanks

[@PeteHowlett]

Send me your address via pm and I'll send you some 80 grit ex wide belt sander paper that I got for next to nothing from eBay. We use it for all our boards and neck carving :)

[@Jdyke2059]

Completely unrelated to this video BUT I'm going to restore some older guitars. Can you tell me the best way to remove old finish from guitars? By he way your content is awesome! Joe D.

[@paulrautenbach]

Susan, have you previously explained why these particular radii are used for a guitar?

[@SusanGardener]

+Paul Rautenbach tradition. They are Martin radii. I might eventually use different radii if I want different tension in the top or back.

[@staryjanek]

Brilliant stuff thanks for sharing. One question though. How or where do you obtain the 25 and 28ft curves to make those "rails". To me , this is the most difficult part of this. Thanks mate John Z

[@SusanGardener]

+john zarecki Pythagoras. Check the Building the Radius Jig video kzbin.info/www/bejne/sKivmWdnia2IZ68

[@vChilem]

You can download a free CAD program like FREECAD or other and draw a 25ft or 28 ft radius arch. I follow the Cumpiano book and a radius dish is not needed at all.

[@hawaiithomson]

Impressive

[@shaunwhiteley3544]

Love your videos, the time and effort you put into what your making, have you thought to make it a bit easier by using a cnc machine? Have a look at MPCNC , mostly printed cnc. Just a suggestion as I like watching how you tackle each issue 😀

[@SusanGardener]

+Shaun Whiteley CNC is somewhat out of my price bracket. If I had the money I'd probably buy the radius dish :-)

[@alancordwell9759]

I saw this pop up in my subscriptions and I thought 'Okay, so she's going to build a satellite earth station...' nothing would surprise me Sue!

[@SusanGardener]

+Alan Cordwell A friend saw my previous video thinking I was building a huge 15' wide dish and wondered what I needed such a huge thing for :-)

[@andycoombes]

Impressive.

[@MichaelScottPerkins]

I absolutely adore your videos! I was shocked when I saw this one, because you've made a 28ft. radius "jig". I have a design project that requires me to determine the radius of a partial circle curve. In other words, if I draw a straight line between two points that I know are 44" apart, and I know that from the straight line to the very top of the curve is 8" what is the radius of that curve? If the straight line were perfectly at the diameter, then it would be easy. In other words... when you made your jig, you had the radius (28ft). I need the opposite, as I am building an arch rather than a bowl.

[@SusanGardener]

+Michael Perkins your radius is 34.25". You can verify this as you have a triangle with the hypotenuse your radius 34.25. The other 2 sides are 22 (half your chord) and 26.25 (34.25-8). Square these 2 values and you get 34.25 squared.

[@MichaelScottPerkins]

So the radius of the circle (curve) is equal to the hypotenuse (c)of the right triangle created with: a(sq) + b(sq) = c(sq). In my example, would that not be... 8(8) + 22(22) = c(sq), which is... 23.41" ?

[@SusanGardener]

+Michael Perkins No. Wrong triangle. The radius of the circle goes to both the end of your 44" chord and to the top of the arch 8" above the chord, so the formula is 22*22 + (r-8)(r-8) = r*r.

[@MichaelScottPerkins]

Well now I need a rag to clean the wall behind me. My head just exploded. Ha ha ha... Thanks so much for the help!

[@msueag]

I got to 2:10 before exclaiming "GENIUS"! So simple, yet very clever :-)

[@tkarlmann]

What are these radii for?

[@tomahoks]

tkarlmann She makes a guitar top and bottom wood boards.

[@atowning]

I like that

[@joshmyer9]

I fear I'm going to spend my whole weekend figuring out what the actual shape here is, entirely from your off-the-cuff 28.5' comment. The perils of having a rusty maths degree: "I'm pretty sure there's a clean solution for this, now to jus spend four hours deriving it…" =) The bowl trick is very nice, btw. I'd probably put a little light underneath of it, to make the gaps easier to see, because I don't trust my attention span to check all the way around it every time.

[@thenextjam]

legend

[@barryducret1052]

I thought you were into maths, geometry being part of maths should have told you that an angle in a segment of a circle is always the same. Therefore it wasn't necessary to make an arc on the track part of the contraption but instead make an angle on an extended trolley part of it. I hope I have made myself clear but it difficult explaining without being able to use diagrams.

[@allenrussell1947]

Great video and, as always, an ingenious solution. If I may, I have a great deal of difficult hearing you. At full volume I can barely hear you speaking.

[@edadpops1709]

I see a cnc router in your future!

[@Iazzaboyce]

OK for bananas but oranges could roll out.

[@FretFriendGWaL]

Your video's tend to be very quiet which is a shame. Great video's...

[@tomahoks]

NG One Seven Yeah, I 'd recommend wireless mic.

[@LiloUkulele]

put the dish on a pin and spin it!

[@paul1962uk]

speech even

[@StickyBit7777]

a pegboard table would allow a vacuum to hold down the work piece.

[@groovin2theblues323]

Would a sanding table have enough suck to hold it down?

[@paul1962uk]

speech

[@missanabiekeith]

Over kill

[@NeverTalkToCops1]

Too much labor/expense/noise/dust/bulk. Just buy a CNC dish. Who uses a 28 ft. dish? That's an extreme and unecessary amount of doming, especially for a soundboard.

[@SusanGardener]

28ft is about right for a steel string guitar soundboard as it gives the perfect neck break angle. You say ‘extreme’ but the doming is 1.6mm across the width of the soundboard. I’d advise against having a flat soundboard as it’s structurally weaker and looks concave when the light hits it - it looks weird. I’ve seen the comment “Just go out and buy...” for a lot of the tools I’ve made. Not all of us have the money to go buy all the specialist tools you need for guitar making.

[@groovin2theblues323]

@@SusanGardener Making is part of the art, isn't it? Otherwise, you would just go out and "buy" the guitar... Love what you doing. I'm learning a lot by watching your videos. Thanks, Susan.

[@groovin2theblues323]

I need to take a math class.

[@markbrown1412]

If you fashioned a much thicker piece, a glued up 3 inch thick wood base for example, to glue the mdf onto, you would be removing significantly less material from the piece. The thick piece would not be so apt to distort. Although clamping this thicker and more stable piece, in four places, would Go a long way to contributing stability to the piece while you are routing The dish shape.