Simplest way to create a wood radial rosette

[SnowManSnow]

Hi guys. I'm at a place in my building where I'm at a bit of a standstill as I save up for something, so for the last few months I've been doing online courses, reading, and just getting better at using my planes and such. I'm finding this "quiet" time has been a great time investment IMO. One of the things I want to practice doing is making a radial rosette. My first impression process would be the following. If there is a better way, please let me know.

1: Cut out the circles from the various woods involved in the rosette with the outside diameter being the same as the outside diameter as the finished rosette.

2: Tac them together in a stack.

3: According to how many sections is desired (divisible by four and probably 16 total sections) mark off equal "halves" through the centerline.
- I'm not quite sure how to get these measurements exact yet. I need something like a miter box..? (suggestions?)

4: Using a fine saw and somehow keeping it at 90degrees to the surface divide the circle down the lines.

5: Take the pieces and arrange them in the desired order.

6: Glue them all together with CA? Or is it best to use wood glue? Or does it matter?

7: After the new circle has dried use my radial router cutter that I use for cutting rosette channels to cut out the desired rosette.

_

Again, this is from the mind of someone who hasn't done this before. So if the process is wrong, it isn't going to hurt my feelings for someone to make it known.

Thank you for any advice / helpful insight.
Peace

[Truckjohn]

Head on over to the OLF forum and check the video tutorials section. There is a great video tut on doing segmented radial wood rosettes.

[Quickstep192]

I think this is the article Truckjohn is referring to. Pretty cool. https://www.ericschaeferguitars.com/...basic-pattern/

[emmsone]

The way I did mine was fairly simple. check out the pictures from my build thread here http://www.acousticguitarforum.com/f...=463946&page=2

I'll briefly explain again my process.

I first cut a wedge on a chop saw that was exactly the angle required that added up to 360 degrees with the number of pieces i wanted.
I then cut some squares out of the material I wanted to make into the radial rosette.
I then placed and clamped the wedge on top of the square of rosette material and tried to align the centre line of the wedge as best as possible with the grain direction in the square.
Because the block was fairly high it worked both as a edge guide AND a 90 degree / vertical guide for my japanese saw.
I then used a square cut piece of wood and 180 grit sandpaper to make sure each edge of each piece was clean and flat and square. I would preferred to have used a shooting board and a plane, but i didn't have a plane at this point.
Once i'd cut my 16 pieces plus a few spares, i placed them onto a board onto which i'd drawn the circles that were the size of the rosette and with the angled lines showing where the pieces should sit to fit together perfectly.
I then covered this board in parcel tape because although i wanted to make sure these pieces didnt move, i needed to be able to remove the rosette afterwards, superglue does stick to parcel tape but its not as fixed as it would be had the rosette been glued directly onto the board. I would have preferred wax paper, but apparently its not that easy to acquire these days.
I then glued with one drop of CA glue on the underside of one piece down onto the board.
I then placed each piece individually working off the original piece and used the thinnest CA glue to wick into each joint until I had gone all the way around.
15 of the 16 pieces fit fine and square, the last piece needed a tweak in angle to get a perfect fit. this wasn't that awkward to do but a good reason to have the spare pieces.
I then used the stew mac dremel circle cutter to cut it into a real circle shape.
I then carefully peeled the brown tape off the main board leaving the rosette intact and sanded the bottom, the superglue can and will wick underneath the other pieces too so to get a smooth underside sanding is required.

Then you just rout the right size channel in your soundboard and inlay it.

Hope that helps
David

[Aubade Acoustics]

There are many ways to do it but if you are only doing a few one option is:

If you have a drawing program on the computer you can draw the rosette outer dimensions and split it up into how ever many sections you want to use. Print it out and use it as a guideline to cut and glue the pieces. It won't be perfect but if you leave a little extra it is easy to sand and fit. I would route the rosette pocket in a scrap and use it for taking outer measurements and initial fitting so you don't chance damaging the top.

If you plan on doing a lot of rosettes:

I made two jigs to do the work. The first jig holds 16 small rectangular pieces stacked and taped together. It is used to route the inner and outer radiuses of the rosette pieces. They then get transferred to another jig that i run on the table saw to cut the beveled cuts that get glued together to make it round. I prefit the pieces in a piece of teflon with a pocket routed in it the same size as the final pocket on the top. Wick CA in the joints and pop it out. The teflon block has holes drilled through it where the pocket is so i can use the eraser on a pencil as a push stick. I make sure and keep the teflon clean and wax it with paste wax to eliminate the glue from sticking. Most come out clean.

[murrmac123]

Originally Posted by emmsone

15 of the 16 pieces fit fine and square, the last piece needed a tweak in angle to get a perfect fit. this wasn't that awkward to do but a good reason to have the spare pieces.

I applaud your commendable attention to detail, but why would you spend time getting the 16th piece to fit perfectly .... or even putting a 16th piece in at all ?

It's going to be concealed by the fretboard extension once the guitar is assembled ...

[emmsone]

Originally Posted by murrmac123

I applaud your commendable attention to detail, but why would you spend time getting the 16th piece to fit perfectly .... or even putting a 16th piece in at all ?

It's going to be concealed by the fretboard extension once the guitar is assembled ...

Actually in this instance its primarily for structural reasons, i've found it's much easier to deal with the rosette if its in one piece. It's much more stable like this and can even resist small knocks and bumps.

On one of my first rosettes I had one joint let go which i thought would be fine, even being careful while moving it about those other joints between the pieces that are only held together by wicked CA glue are pretty fragile. it doesn't take much, the weight of the rosette itself if you are holding it at the other end, or a small bump can cause a cracking / folding of one of the joints. If you're lucky it will still stay together and you just turn it over hold it flat and add more CA glue, but if you're not, all that effort to get a perfectly round rosette will mean your joint re-gluing attempts will have to be perfect in order to get that back.

Side note, and one that almost deserves its own discussion at another point in time, while i'm writing this i'm wondering how much difference this structurally better rosette makes to the vibration / flex of the soundboard? its going to act almost like a mini brace / plate.
The 'open ended' rosette could / would / might allow more twist and flex in the soundboard (but once its all glued in, perhaps not). I also know rosettes were originally purposed to reinforce the soundhole and surrounding area, so in that regard being structurally solid is a good thing.

apologies for the off topic rambling diversion.

[Truckjohn]

Steve,

That is a slick circle cutter....

What is it?

[Halcyon/Tinker]

I do it a bit differently.

I use off cuts from the back of the guitar in question.

After marking the centreline (so it's visible without the edge offset), I use the edge sander to flatten the end of the back at right angle to the centreline. Then I use the fretslot blade to cut a strip off the end of the back, then bend it on the hot pipe.

I route a channel for it just a smidge wider, shellac the channel and ca it in. Then carefully rout purflings channels on either side.

[Halcyon/Tinker]

[Halcyon/Tinker]

Of course the glue joint separates on the pipe so you have to bevel that edge a bit for a nice fit.

[mirwa]

Originally Posted by Truckjohn

That is a slick circle cutter....

It was made by a gentlemen in turkey, I can try and find his details, he makes cabinetry tools by hand and sells them for a living, not really expensive from memory.

Lot better then some of the snake oil tools you see getting pushed out there.

Steve

[Codfather]

Originally Posted by Truckjohn

Steve,

That is a slick circle cutter....

What is it?

Lets see a pic

[mirwa]

Originally Posted by Codfather

Lets see a pic

A link existed that showed my circle cutter being used in the manufacturer of a rosette, I was unaware linking to external sites was not allowed at the time, so the link was removed.

Steve