Dovetails on the 'Bot

[jTr]

I've had a great day with my Shopbot - engraved some aluminum, cut 30" diameter circles out of solid 5/4 poplar, but what's really iced the cake is I finally tested the dovetail drawer jig design and files per Gary Campbell's web article.

Honestly - I cannot believe I've not seen more discussion about this article. If you make drawers and you own a Shopbot, you owe it to yourself to try this out. Not only does he give you instructions to build, He's shared the custom program to run it.

Furthermore, I am blown away at how well it is written- constant stream of pop-ups coach you through the entire setup and adjustment process. The results are the best I've ever been able to produce with any jig, and I've spent plenty of time and money on a variety of them. Once calibration is complete, you literally just answer a series of questions about the stock dimensions, and it automatically plots the number of reps to generate dovetail joints with cnc accuracy. It even lifts the bit to a safe height to clear the jig, then parks a foot or two away so you can swap work pieces, and politely asks if you'd like to cut another. Brilliant!!!

Thank you, thank you to Gary - though his career has taken him on to other places, what he's left for wisdom and instruction for full utilization of our machines is invaluable.

Lovin' life with my bot - it's making my business safer, more accurate, and much more enjoyable.

Any newbies out there struggling, please, keep at it - I'm at about 20 months running mine, and things have become so smooth and intuitive now, I am absolutely giddy about it.

Photos show my first test cuts in 5/8" stock. Wow!

Try it!

jeff

[kevin]

I wanted to try Gary program
Speed how fast compared to decanted dovetail machine?

[jTr]

Kevin,
I assume you're referring to the porter-cable style jig he modeled it after, which oddly enough is one style I have not tried.

That being said, one clear advantage is this setup can run two pair of drawer parts since it is 24" wide, and incorporates an offset fence on the left and right. This means two cycles of clamping and running the file completes a drawer, instead of 4.

I went to 34" between fences, as I may use to construct case pieces in the future. The calibration routine can accommodate whatever width you choose.

My old favorite was a Keller "Katie" jig. I liked the full through dovetails it produces, but it required two routers with two separate bits. Found myself re-adjusting slipping bits quite frequently, and often wearing out a bearing after just a few hours of operation. That and variances that crept in due to humidity changes required removing and replacing backer boards in order to fine tune. Now I can tune it digitally by the thousandth.

[kevin]

Thanks for the response

I was talking about a stand alone dovetail machine

[bobmoore]

I must have been asleep. Can you point me to the program under discussion?
Thanks Bob

[adrianm]

http://www.shopbotblog.com/index.php/2008/08/dovetail-and-mortise-jig/
http://www.shopbottools.com/labfiles/garydovetail.htm
http://www.youtube.com/watch?v=4Aw4lElTecg

[jTr]

Kevin,
Looked at a few dovetail machines, such as the Grizzly, but $3-$5k investment in a single purpose machine is tough to digest for a one person operation.

Also - for every new machine, there's a new curve and "attitude" to work with. Figured it was more sensible to save the spending and simply expand on my good working relations with the 'bot.

All too often, squeezing multiple operations from one machine does not turn out so well. However, as usual, the bot excels at yet another task, and the time invested will pay off for me, as it has in so many other ways with this machine.

In the past, I've tried outsourcing to a local company who had a dedicated dovetail machine. May have been a bit faster, but fit and finish were disappointing.

[Simops]

I could be wrong (more often than not I am) but this is only possible on a table based CNC and not a Buddy?

Cheers

[jTr]

Michael -
Good question - not sure. I understand the X movement is carried out by the table instead of the gantry - as long as you could hang a board off the end and not hit any table support systems with it, I would think so.
Anyone else have any experience with this and a Buddy?

[Simops]

I'm pretty sure it can't ...... The Y-axis (X-axis on my setup) travels along the gantry which is fixed in the middle of the unit with the table movingunderneath....so no way that I can see how to fix anything vertically!

I think the only way to do it on a Buddy is as per the other forum contributor that has created a angled jig for dovetailing that is quite ingenious.....can't remember who it is now?

Cheers

[Bob Eustace]

Jeff and Mike - on the Buddy you are limited to dovetails on boxes no more that 5 inches long. Bugger! However there is a clever guy messing with a horizontal solution using odd cutters (posted in the last few months but I am hopeless at searching!). I fitted an Incra TS/LS positioner to the table saw and plonked a router on the end. This lets me do dovetails and box joints very quickly and accurately. It does a fantastic job on double dovetails. With my limited knowledge I dont know of any jig that will let you do this???

Its worth looking at these short videos if dovetails are on your menu. Of course there are very cheap automated routers appearing on the market and I reckon these will be common place in a few years. No videos on these yet!

http://www.incra.com/product_tsf_tslsjoinery.htm

http://www.incra.com/product_tscombo.htm

[bleeth]

The guy is Gene Burkhart. There are other ways to do dovetails with boards laying flat on a cnc-Check it out on the Thermwood forum. (If you need me to tell you the exact link you probably don't really want to do it!!!:D)

[Bob Eustace]

Thanks Dave - never looked at that forum. Here is a link to a video for anyone following this.

http://classiccustomwood.com/cnc-services/drawers/

[jTr]

Kevin,
A better qualified response regarding speed, as I've finally got back to shop today. (snowed in for 3 days - 36" official, 48" higher elevations - no, I'm not in Alaska, but South Dakota. Looks like a long winter ahead!)

Ran a full batch of drawers today - including a couple test cuts, dry fitting and work piece clamping / swapping, it took about an hour to do 5 drawers with sides measuring 9.625 wide.

File is set to cut pins/tails at a feed rate of .50 ips.
Averaged about 2.5 minutes from hitting the start button to the gantry being parked upon completion of the routine - that's 44 pins and tails completed in a single cycle. One more and the drawer is ready for a dry fit.

Hope that helps.

jeff

[kevin]

Jeff
Thanks for the reply
I'm debating is it better a dedicated machine?I know in a year or 2 I will have to make dovetail standard

I will invest the time and set up the program. I miss Gary post sometimes I would be there reading and going dah still have Brady

[jTr]

Kevin,
Just read your post on show and tell - I can identify - can be real tough to educate the buyers on quality. I know some custom shops have said they are rarely asked, but lately, I've run into more and more people expecting solid wood dovetail drawers, and soft close slides, and soft close doors and.....

Glad I've found a method that is efficient and turns out quality joints- like anything else, takes some time to get set up, but second nature in short order.
Feel free to send a personal message if you have questions - had a few head scratching moments, so if you get stuck/unsure, I'd be happy to answer questions.