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WTI
Sat 20 October 2007, 17:21
We have been thinking of practical ways of cutting dovetail joints using the MM.

Some way of clamping boards vertically, yet repeatably and squarely.

domino11
Sat 20 October 2007, 18:55
James,
I dont have my Mechmate done yet :( but maybe it would be possible to have a slot cut in your spoilboard close to one end and then have a clamping surface under the spoilboard at 90 deg to the slot. Then all you would have to do is clamp the board in the slot , have it sit proud of the spoilboard and then use the MM to cut the dovetails with a dovetail bit.. The height above the spoilboard would be critical, but repeatability could be achieved with a jig of some sort. What do you think? Gerald have you tried this ?

smreish
Sat 20 October 2007, 19:00
I have tried it with some degree of success. Natural woods with Grain..not so good, very Cutter sharp and NO VOID plywood a must. MDF or TruPan, not so bad. The shop next door to mine actually turned their spindle 90% to Z and made all the cuts plunge with a standard dovetail bit! It work great, but set up was a bugger. In the end, they found it quicker to use their PorterCable dovetail fixture board to be quicker because it cuts both halves of the joint together.
That was my life experience talking guys....good luck.
Sean

domino11
Sat 20 October 2007, 19:15
Sean,
Yes, I too have found that sometimes some jobs are just plain suited to certain tools. Somtimes just because you CAN do something with a particular tool, ie a MM, doesnt mean its the best choice. :)

WTI
Sun 21 October 2007, 20:27
We only use through dovetails, so no chance of us cutting both parts at once.

We are fishing for ideas on how to make the jig square and repeatable.

You can cut almost any wood product into dovetails, you just sometimes need to control tearout.

The problem with those Leigh or PC dovetail jigs, is that they are not deep enough to cut more that one 3/4" board at once. You can just barely get two 1/2" boards in to the clamps.

Setting up a stack of boards on the MM and letting it tear into them would let the MM pay for itself in a week.

lunaj76
Sun 21 October 2007, 22:22
James,

I have heard of nested based machining of dovetail drawers but out of sheet goods. Sound like you are just using solids. Found and interesting link. I have no affiliation with them. Just thought I would pass it on.

http://www.routercad.com/WebPages/Dovetail_DrawerCAD.html

driller
Sun 21 October 2007, 23:25
if you make the machine longer by a foot or more, you can build a vertical wall on the end. that allows you to lay your sheet goods on the normal table, or to mount parts vertically on the space at the end.

you could convert a section of the normal work space to offer similar mounting.

and you could mount the router horizontally, or make it adjustable so you can manually (or automatically) change the head position.

Dave

Gerald D
Sun 21 October 2007, 23:56
http://www.iedu.com/DeSoto/cnc_joinery.html
http://www.iedu.com/DeSoto/JBot.html
http://www.talkshopbot.com/forum/messages/30/12031.html (http://www.talkshopbot.com/forum/messages/30/12031.html)

Regnar
Mon 22 October 2007, 10:58
here's a link with some info for how to do it with sheet goods. http://www.woodweb.com/knowledge_base/Dovetail_DrawerBox_Joinery.html

The bit is only 45 usd. Not bad if you can become pretty quick with autocad.

Marc Shlaes
Mon 22 October 2007, 11:18
Russell,

Have you done it with that bit?

Marc

Gerald D
Mon 22 October 2007, 11:41
More pics from here: http://www.routercad.com/WebPages/Dovetail_DrawerCAD.html

http://www.routercad.com/Photos/Screen%20Captures/NestedDovetailDrawerI.jpg

http://www.routercad.com/Photos/Screen%20Captures/NestedDovetailDrawersI.jpg

Gerald D
Mon 22 October 2007, 11:45
Some more here:
http://www.actioncnc.com/cncgallery.htm

Regnar
Mon 22 October 2007, 15:59
Sorry Marc but I have not... yet that is. I am still learning but the concept works inside my head. Just figure I would post the link and share.


1/2 Material Link 45.00
http://www.woodworkerswholesale.com/product_p/fsh1065.htm
5/8 Material Link 45.00
http://www.woodworkerswholesale.com/product_p/fsh2185a.htm
3/4 Material Link 45.00
http://www.woodworkerswholesale.com/product_p/fsh2185b.htm

I have searched every where for a how to step by step but havent found it yet.

Regnar
Mon 22 October 2007, 16:33
This is a nice program that will help you out visually and mathematically set up your dovetails. It will tell you the depth, width of both tails and pins. You can also change bit size. Now this will not help you out for say with the above bit but should help with planning. Also alittle more if you are able to import pdf. files into your cad/cam you can print the template to pdf. and import it into your programs. Vectic I knows allows you to do so.

http://www.internetwoodworking.com/w5/dovetail.html

The website doesnt have a screenshot so I attached one here.

WTI
Mon 22 October 2007, 22:05
Wow, the MM website is an amazing resource!

I like the hand crank wheel idea as a solid way to clamp the wood down. I wish the pics on that site were more detailed as to the actual construction. Getting the wood square to the MM still seems to be the idea that is eluding me in all of this.

Those links to the HB Dovetails are great too. If the customer did not want through Dovetails, that would be the way to do it, hands down.

driller
Tue 23 October 2007, 20:49
if you build an end to the machine so you can clamp the sheets, you can easily put in a fence to use to align the parts to.

Dave

Gerald D
Tue 23 October 2007, 23:13
If you put a vertical table at the end of the main table;

- consider that I have only allowed for the router center to move 50mm [2"] past the end of the main table. Suggest you extend the x-rails if you want to go this route.

- we often use G-clamps at the end of the main table, with the screwhandle pointing down. Adding a vertical table there will make G-clamping impossible. A removable vertical table could be the answer.

Marc Shlaes
Wed 24 October 2007, 06:53
I really like the track of engineering the pseudo-dovetail bit and the straight bit in order to cut everything in the flat. That is what the "big-iron" software is doing. The Thermwood router with their eCabinet proprietary software is doing it also. The joint strength will be double what it needs to be and the joint looks about 98 percent of a standard dovetail.

I have made a zillion dovetail drawers and creating a dovetail jig that takes the place of a standard handheld router jig but uses the MM to simply move the router is certainly not an order of magnitude improvement in the process.

Let's put our heads together and make the big jump in productivity by doing everything in the flat using the bit for 1/2" material that Russell found!

WTI
Wed 24 October 2007, 16:16
I like cutting everything flat too, but all we cut are through dovetails, so it just does not seem possible w/o adding an additional axis to the MM.

G, I like the vertical table idea, it could work with a few access holes for the G-clamps or F-clamps. I also like that with a setscrew or two it could be adjusted square.

Marc Shlaes
Wed 24 October 2007, 20:47
Yep, in the case of through dovetails you are absolutely right. We'll all help think that through as well.