# how do you do this?



## bruce thom (Apr 2, 2008)

I have several pictures of a unique Grease box with curved dovetails
Wondering how to do this.
Your help is deeply appreciated
Bruce. 
Tired and Retired.


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## DaninVan (Jan 1, 2012)

Beautifully crafted piece. Now _that's_ art!


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## Cherryville Chuck (Sep 28, 2010)

That is pretty. You'd need a dovetail with a bearing on the shaft so that you could follow a pair of templates. You'd need a circle cutter to make the templates, the radius has to be perfectly circular for it to slide. I think the radius would be slightly different for the two cuts since on one you'd be cutting the profile for the box with the curve between the pivot and the bit and on the lid the profile would be on the opposite side of the bit from the pivot. I think the difference in radius would be the diameter of the bearing plus a tiny amount for clearance (or sand it to fit).


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## Shortslvs (Jan 13, 2013)

I wonder if this peice wasn't hand worked. I am sure it can be done with power tools, but some things are actually easier to do with hand tools and this just has that look to me.

Looks like something fun to fiddle with and make pretty just because you can


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## FCarvi (Mar 5, 2014)

Thats a really nice piece of art, you can build a jig, 2 concentric circles where de center is the pivot of the piece


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## neville9999 (Jul 22, 2010)

*The Mighty Swing Arm*

Bruce I would normally jump on a post like yours but I have not been well so my mail is behind, Years ago we would make curved receptions desks and they were a lot of trouble until we built them a backbone, a curved center wall, these walls were built just like stud walls are built and were buried inside the construction and they were about 60mm thick when they were plated, so as the build progressed then they were never to be seen again however the stiff spine does do its job and it provides a focus point for all of the desks components, the curves varied but were rather gentle considering that the desks were 7 feet to 9 feet wide, so how do you cut the curved top and bottom plates for the curved stud wall? Well seeing you asked, you lay out as many large sheets on the work shop floor so that a swing arm can be built to attach a router to, my memory says that some of these swing arms were 25 feet long but we fixed the swing arm pivot point down to the floor with a ramset gun, there is nothing like a bullet to send a hardened nail into the concrete floor and they are fun to fire, so with the plate on the floor and a bearing pivot plate above that then the swing arm itself did not need to be that neat, it just could not bend as you swing the arm and cut the outside of the curved plate and bear in mind that there is a router attached to the other end of the arm and then move the router along the curve and cut the workpiece we actually made a permanent adjustable (in out from the pivot point) router base, that we fitted to many swing arms as we needed it, so move it in towards the pivot point, shorten the distance, and cut the inside of the curved wall plates, now remember this, the direction of cut is not always the same as the outside of the plates are cut in one direction and the other side of the plate is cut in the other direction, the cutter always needs to run in the correct direction, then build the wall, it looks like a normal stud wall but it is curved and as long as the pivot distance is changed to suit then you can get any curve that you wanted, and here is the cream, if you attach any piece of material to the sheets above where its fits in the full sized set out, one that we always drew onto the sheets, then you can use the same swing arm set up to correctly cut any other curved parts you will need, we cut many other curved parts right off the full sized set out like other curved rails and cabinet parts.

Now I would build such a device to cut your curved dovetails, your swing arm does not need to be 25 feet long but it does have to give you the curve that you want, I suspect that the swing arm would be about 6 inches but you would need to set it out and see what swing you would need to get your curve and this system will work for your box as the inside of your dovetail is not the same curve as the outside is and I am sure that you know that but if all the cuts are done with the swing arm in the same pivot point and the item sits directly on top of it proper home on the set out then you will get the correct cut, the best part is that I would make the tops first and then make the bottoms, make the dovetail to be tight and then just adjust the length of the swing so that you can just loosen it up enough to allow the top to slide across nicely. So no hand finishing as the whole joint is cut and finished by the router on your swing arm.

Every one who knows me will know whats coming now, if you make your jigs very nicely then they will last forever and you can use them to make thousands of these boxes, when you do then send me one, these types of jigs are not made for one box and they are made to make thousands ogf any item so quickly that you can make a buck out of selling them, you will never make money on this box if you make the joint by hand, I am a award winning cabinetmaker and I would not even think of doing the joints by hand.

And as I have said many times, "never make one of anything" as when you start to think about making a hundred of something then then you will be a better woodworker, and maybe make a dollar or two. Neville


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## JOAT (Apr 9, 2010)

No doubt about it Neville, you are my hero. :dance3:


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## bruce thom (Apr 2, 2008)

Neville and all:
TNX
I am working now on a jig to set on the router table with a swing pivot.
When finished I will post a picture for all to see and a box for Neville as well
Thanks again.
Bruce


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## bruce thom (Apr 2, 2008)

*Viktor , who made this replied*

Hi, 
I did build a jig consisting of a piece of plywood with a pin and an opening for router bit. The jig was then clamped to the router table. I drilled a hole in two halves of the box, placed one part on the pin and rotated it cutting a slot with dovetail bit. Then I re-clamped the jig and cut again. Same with the other half. To achieve good fit I initially estimated needed radius and then did it by trial and error cutting in very small increments. It is critical (!) to always move the jig/pin in one line directly to or from the router bit (along the radius). Otherwise the arches you cut won't be concentric. I might have referenced my jig of the edge of the table to achieve that, I can't remember now.

Good luck!
I will post my jig when finished.


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## bruce thom (Apr 2, 2008)

*How I did this..*

Enclosed photos of jig and finished prototype
Built a jig with pivot hole, 4/20, to house a pivot hole drilled in boards.
Jig moves toward bit or away depending on slot desired.
Jig is squared to the table with side boards.
Slot is aligned with the dovetail bit so it is square to it.
Boards held in place with a 4/20 bolt with washers so that it will rotate.
The first board, identical to second is cut first and the second is aligned carefully with it.
Final example will be posted.

Thanks for all your inputs.


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## neville9999 (Jul 22, 2010)

Bruce jig making can be a pain but you are on the correct path here, to do any curved cut then the router has to be attached to a swing arm, time will get it correct. best of luck Neville


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## bruce thom (Apr 2, 2008)

*I did it ! here are the pictures*

Final Pictures of My Curved Dovetail Grease box, from assembly to final product
Hope this is useful to others.


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## neville9999 (Jul 22, 2010)

Bruce the swing arm looks perfect, I hope you had a fun time doing it, the finished product looks very professional. Neville


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