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Here's how I route out "f" holes using an acrylic template.

Once the plate is carved to the rough convex and concave desired thickness I trace on the "f" hole onto the convex side of the plate. I then give that part of the plate a wash coat of shellac in order to stiffen the fibres. Once dry I put masking tape on as extra insurance against blow out from the router bit.


Next I attach my acrylic template to the concave side of the top plate. I put some masking tape on to the convex side of the plate then use doublesided carpet tape to attach the plate to the template. Note the template also has small brad nails through the centre line of the template that are lined up with the centre line of the tape.   Next I clamp the template/top plate onto my carving dish as shown below.


I use a 3/8" template following guide in my router with a 1/4" upcut spiral router bit. If you use this method you will have oversize your template to compensate for the template following guide.



I cut out the f hole in one pass and have yet to experience blow out - though on a practice piece I did have the router jump once. The cause was not clamping the template down well.

Here's the final product....voila

Anthony Z38963.6918981482

Good Stuff!!! Keep going...

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Joe Beaver
Maker of Sawdust

Great stuff!! We want more!!

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Now that is really cool!!! Thank you...

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Joe Beaver
Maker of Sawdust

Thanks a lot Anthony, file saved that will be very helpful for my mandolins!

You rock dude!

Thanks Anthony!

Same as Serge, I'll try to adapt this to Mandos...


-Mark

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Pullman, WA

The more I know, the more I know I don't know.

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Nice stuff, Anthony! I'll add this to the plate carving info you sent. You archtop boys are a special breed. Thanks for posting.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Very nice, Anthony.

I use a drill, a coping saw and a knife, but it is very difficult to get the walls of the hole perfectly vertical and making the curves graceful. I will have to try your method out one of these days. Thanks!

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Rian Gitar og Mandolin

Anthony
I've used a similar setup with the template against the glue joint as you're doing. I used a pin router setup, however, with the template down against the table with the router above. The router was mounted to the spindle quill on the Shopsmith so that it could be plunged into the cut. A sleeve around the pin was removed after the roughing cut to leave material for a finish cut.
More than one way to skin the feline, I guess.
Nelson

Arnt you are right -- the reason I went with this set-up is to ensure the f holes are cut perpendicular to the ribs. I don't have the confidence to cut them with knife and a coping saw. Mario probably has his done perfectly with a knife before the shellac wash coat dries on mine

Nelson -- I'd prefer to do it with a pin router as you used to -- or even better the way you do 'em now with a CNC Thing about this method is that it works great with the tools most folks have on hand.

BTW: the only thing I do differently now is I use a Porter Cable router -- I pitched the Crapsman plunge router -- what a piece of junk