Dovetail Cutting

[Steve Hinde]

First time with construction and I need some advise on the dovetail for the neck. I saw the Stewmac video way with the cutter head, but I have to hand grind the cutters and make the jig. Really scary. Or just cut the male side with a band saw with the neck held at the proper angle for the neck relief? Any other ways? What do you do?
The other side in the body will have a jig for routing. Not worried about that so much.
Of course these are only rough cuts with the final fitting by hand for depth and alignment.
I have done guitar necks and the bodies before with the router jigs, but the rounded cut against the body has to be right. Little worried about the free-hand cut on the band saw and want some repeatability for multiple necks.

Steve

[Chris Baird]

For repeatability you will have to go with the hand ground cutter( at least as far as I know). For cutting with the bandsaw you can make a jig(a la Dudenbostel http://www.thefishnet.com/makemandolin/newmake.htm ) and practice till you are confident you can make the cut in a real neck.

[Jim Rowland]

Hello:
I agree with Mandoplyr. I've been using the simple Dude jig lately and am surprised at how well it is doing. I leave the line on my traced pattern to reserve a little extra wood for final fitting. Don't forget to chop the neck at the required rake angle before cutting out the dovetail on the jig. I've considered and reconsidered trying the Don MacCrostie rig,but it looks like he cuts the entire depth of the dovetail configuration in one pass..a lot of crossgrain wood to take in one swell foop without some serious risks.???
Jim

[bobz]

Hello masamando
I went the Don Macrostie route and made the jigs and ground the cutters for his method. If you`re planning to make a lot of mandos I would say this is the route to take, but if you`re going to make one or two, do it by hand. even after band sawing there`s still going to be a fair amount of hand work in fitting the dovetail but I thick you`ll find it enjoyable work.

grow - No problem machining the dovetail with the moulding block. As long as the cutters are sharp and you feed the neck over the cutter block slowly there`s no tear out. Excellent results.

[Jim Rowland]

Thanks for the info,Bob. Verrrry tempting! I do have an ancillary problem in that I know nothing about metal working. I've clung to the hope that Mr. Don would offer the cutters commercially,but I have to assume that he considers the details propriatary as he certainly has the right to do. I can get the cutter head easily enough,but if you get the chance and have the inclination,could you give us some tips concerning metal stock,machining techniques,etc? I would sure be obliged.
Jim

[bobz]

Hello grow
I`ll descibe how I went about making the cutters. The first thing I did was assertain the shape of the cutters by producing a geometric drawing. When the cutter reaches it`s highest point above the saw table the cutter is at an angle, so the shape of the cutter is not the same shape of the profile the cutter produces. Once I had done the drawing, I then used the result to produce a plastic template, ( a piece of plastic milk carton ). The cutters were the rabbetting cutters that came with the block which I modified for this purpose. The template was then used to mark the cutters with a metal scribe. To shape the cutters I used a 6 inch bench grinder and ground the cutters square onto the wheel to remove the bulk of the metal very close to the scribed line. As soon as the metal became uncomfotably warm I quenched in cold water and resumed work on another cutter. This took quite some time and was done over three sessions. Once this had been done I then set the ginder fence to the angle the cutters required for thier bevel and continued grinding the bevel to the scribed line. Laborious and time consuming, but once they`re done they`re done and they`ll last me my life time. Because the bevels are hollow ground on the bench grinder, sharpening will only require a light touchup with a diamond lap every 50 or so necks.

[Jim Rowland]

Hello again Bob.

Thank you a bunch for your reply! Your excellent description of the process seems doable for me. I will have to nag you with one more question. Is the angle of the bevel prescribed by the mounting angle in the block or could I just use the same angle of the rabbeting cutter used for a blank? Thanks again.
Jim

[bobz]

Hello grow,
Yes, use the bevel angle that was originally on the rabbet cutters. If you`re not sure how to do the drawing, here`s another trial and error method of getting your cutters ground. Make a plastic template from your mandolin plans you intend to use. When holding my cutters square on to a cut dovetail, ( that is the flat side of the cutter is held to the side of the dovetail and with the point at the base of the dovetail ), there is about a 1/16 inch gap from the tip of the curved shoulder to the cutter`s edge. Make this adjustment to your plastic template by drawing a curve from the tip of the template to the 1/16 inch diffrence and recut it. You`ll have to draw this curve free hand using your plans as a guide. Then use this template to grind your cutters. make up some test necks and cut one of them and test in a mando body. You will then be able to determine where modification to the cutters are required. Make slight adjustments to your plastic template and go through the process again. I hope I`ve made myself understood ? It`s difficult to explain in words.

[Jim Rowland]

You've done a good job,Bob. I think I have enough to start with reasonable chances of succeeding. I am much obliged to you for your time and trouble.

Jim