Carl Beckett
12-19-2022, 8:26 AM
Last week tried dovetails on the CNC, pics shown. Some commentary:
Dont ask me about how this clamping fixture is mounted to my machine - it was not made for it but I did it anyway. Do not recommend.
I tried various gadgets in VCarve, and looked at the paid software just for calculating dovetail joints. In the end I decided they were all either limited in customization, or saved little time vs just laying it out myself.
With some mental imagery, laying dovetails of any size/spacing you want in VCarve is a pretty straightforward exercise. Simply assign an end mill cutting bit equal to the diameter of the dovetail bit you want and have at it. For the pins just match the angle to whatever angle the dovetail bit is. These were all 8 degree.
I did use a roughing pass with a straight bit before cutting with the dovetail bit.
The pins are cut with a straight bit.
This was my first attempt, and I left the cut lines line to line with no 'gap'. They are super tight. In the future I will add some gap to design file by offsetting (once I have a pocket vector it would be simple to offset that vector by .003 or so - although there might be a toolpath setting that does the same)
In my pic you see my mickey mouse setup has an old ruler as a spacer against the clamping cam. The problem with this type of BS is that the 'operator' doesnt pay attention and of course the bit tries to cut through that hardened steel and destroys the tip of a bit. Rats. (I still suffer from the occasional crash or dive when doing something new/different, in part because I do too much mickey mouse setup stuff)
Also note - as with a router fixture - you are limited to what you can do with router bits. So the smallest pin dimension is limited by the shank end of the router bit. and you need a bit with enough cutting length to accommodate material thickness. This in fundamental to cutting dovetails with a machine. So if you dont like the looks then go with hand cutting.
The first one took a LOT longer than if I would have just cut by hand. I sold my router jig because I never used it once I got better at hand cut.
Otherwise it worked well and makes it a matter of cut, clamp, repeat until they are all done.
I may at time still decide to hand cut depending on the project, but this has a place. I have some box joints to cut and am pondering whether I CNC those one at a time or gang them all at once on the table saw or router table like I would have previously.
Am likely to keep using the CNC on this little project as a learning curve and getting familiar with the process, then decide in the future what approach fits what objective.
491939491940491941491942
Dont ask me about how this clamping fixture is mounted to my machine - it was not made for it but I did it anyway. Do not recommend.
I tried various gadgets in VCarve, and looked at the paid software just for calculating dovetail joints. In the end I decided they were all either limited in customization, or saved little time vs just laying it out myself.
With some mental imagery, laying dovetails of any size/spacing you want in VCarve is a pretty straightforward exercise. Simply assign an end mill cutting bit equal to the diameter of the dovetail bit you want and have at it. For the pins just match the angle to whatever angle the dovetail bit is. These were all 8 degree.
I did use a roughing pass with a straight bit before cutting with the dovetail bit.
The pins are cut with a straight bit.
This was my first attempt, and I left the cut lines line to line with no 'gap'. They are super tight. In the future I will add some gap to design file by offsetting (once I have a pocket vector it would be simple to offset that vector by .003 or so - although there might be a toolpath setting that does the same)
In my pic you see my mickey mouse setup has an old ruler as a spacer against the clamping cam. The problem with this type of BS is that the 'operator' doesnt pay attention and of course the bit tries to cut through that hardened steel and destroys the tip of a bit. Rats. (I still suffer from the occasional crash or dive when doing something new/different, in part because I do too much mickey mouse setup stuff)
Also note - as with a router fixture - you are limited to what you can do with router bits. So the smallest pin dimension is limited by the shank end of the router bit. and you need a bit with enough cutting length to accommodate material thickness. This in fundamental to cutting dovetails with a machine. So if you dont like the looks then go with hand cutting.
The first one took a LOT longer than if I would have just cut by hand. I sold my router jig because I never used it once I got better at hand cut.
Otherwise it worked well and makes it a matter of cut, clamp, repeat until they are all done.
I may at time still decide to hand cut depending on the project, but this has a place. I have some box joints to cut and am pondering whether I CNC those one at a time or gang them all at once on the table saw or router table like I would have previously.
Am likely to keep using the CNC on this little project as a learning curve and getting familiar with the process, then decide in the future what approach fits what objective.
491939491940491941491942