rgdaniel Posted December 22, 2014 Report Share Posted December 22, 2014 Hi folks, I'm thinking of recreating a breadboard we had lying around, which used tongue and groove breadboard ends. These eventually failed, and I wanted to rebuild it with sliding dovetails for better longevity. I actually did one already, several years ago, but that's a distant memory now and I thought I would explore what the best practice is before I dive in again... For the cuts across the ends of the main central part of the board, I thought I'd use a dovetail bit (duh), then cut the outsides of the end pieces with the same bit, sneaking up on the final fit. My question, is it a good practice to hog out most of the central dovetail slot with a straight bit, using several passes raising the bit in between? Or is it better to just make one full pass and be done? (Obviously you can't raise the bit a little at a time as with multiple passes with straight bits). Using hard maple BTW. Thanks in advance, cheers, Bob Here's the one I did way back when... https://www.flickr.com/photos/rgdaniel/3918293084/ Quote Link to comment Share on other sites More sharing options...
Tpt life Posted December 22, 2014 Report Share Posted December 22, 2014 In maple I would hog first personally. Pun intended 1 Quote Link to comment Share on other sites More sharing options...
woodbutcher74 Posted December 22, 2014 Report Share Posted December 22, 2014 Or you could cut the groove on the table saw. I have better luck on the TS. 2 Quote Link to comment Share on other sites More sharing options...
rgdaniel Posted December 22, 2014 Author Report Share Posted December 22, 2014 Thanks! I was also thinking table saw, potentially. My concern: is there likely to be a problem with the dovetail bit trying to cut two different sides of that groove at the same time, now that the center has been hogged out? Like, if the dovetail bit is not PERFECTLY centered in the groove, will there be unbalanced forces causing a dangerous situation? Or am I just being overly cautious? Quote Link to comment Share on other sites More sharing options...
Tpt life Posted December 22, 2014 Report Share Posted December 22, 2014 Just use feather boards and push blocks wisely. The only reason to hog is to lighten the cut and help clear chips. It does not need to be perfectly aligned. That said, it is typically pretty easy to get very close with the table saw. Line your blade up on center, run the board once from each side. The slot will be centered. Cheat your fence back flipping your board to take two passes each time and your slot will be centered. 2 Quote Link to comment Share on other sites More sharing options...
woodbutcher74 Posted December 22, 2014 Report Share Posted December 22, 2014 Thanks! I was also thinking table saw, potentially. My concern: is there likely to be a problem with the dovetail bit trying to cut two different sides of that groove at the same time, now that the center has been hogged out? Like, if the dovetail bit is not PERFECTLY centered in the groove, will there be unbalanced forces causing a dangerous situation? Or am I just being overly cautious? With the bulk of the material already removed, the dovetail bit won't have that must pressure on it. Should cut pretty smoothly. If you follow the advise that C Shaffer gave above you should be good to go. Quote Link to comment Share on other sites More sharing options...
Eric. Posted December 22, 2014 Report Share Posted December 22, 2014 I don't have a flickr account so I couldn't view your pics. Are you talking about breadboards for a table top? If so... My only concern would be getting such a long dovetail to fit together. If it's even close to a snug fit like it should be, it could take some serious pounding to get the pieces together, even without any glue. And of course, you wouldn't be able to add ANY glue, due to the nature of the joint, so you'd HAVE to make it fairly snug so that your ends don't just slide off the table top at the slightest bump of a hip. It's gonna have to be a PERFECT fit to function properly. My opinion...total overkill to do it that way. There's a reason the breadboard is traditionally made with a tongue and groove and pegs. Spring the joint a little bit and drawbore the pegs if you want it super duper tight. 1 Quote Link to comment Share on other sites More sharing options...
rodger. Posted December 22, 2014 Report Share Posted December 22, 2014 I don't have a flickr account so I couldn't view your pics. Are you talking about breadboards for a table top? If so... My only concern would be getting such a long dovetail to fit together. If it's even close to a snug fit like it should be, it could take some serious pounding to get the pieces together, even without any glue. And of course, you wouldn't be able to add ANY glue, due to the nature of the joint, so you'd HAVE to make it fairly snug so that your ends don't just slide off the table top at the slightest bump of a hip. It's gonna have to be a PERFECT fit to function properly. My opinion...total overkill to do it that way. There's a reason the breadboard is traditionally made with a tongue and groove and pegs. Spring the joint a little bit and drawbore the pegs if you want it super duper tight. I agree with kiki. I think that a really long sliding dovetail will be a major headache to deal with. If you plan on using a bit of glue, you won't be able to dry assemble for a test fit either as the joint will be very difficult to disassemble. I'd go with traditional method of tenons with pegs, with a bit of glue on the center tenon. Quote Link to comment Share on other sites More sharing options...
Eric. Posted December 22, 2014 Report Share Posted December 22, 2014 You really wouldn't be able to use any glue at all. Typically, if a breadboard end is glued, it's only a dab right in the middle, but you can't do that with a sliding dovetail that needs to accommodate movement since if you put a dab in the middle, it will be spread all the way to one end when the parts are put together...which is no good. Ultimately, a sliding dovetail just doesn't make sense for a breadboard end, which is why the tongue and groove has been used instead...for centuries. Quote Link to comment Share on other sites More sharing options...
rodger. Posted December 22, 2014 Report Share Posted December 22, 2014 You really wouldn't be able to use any glue at all. Typically, if a breadboard end is glued, it's only a dab right in the middle, but you can't do that with a sliding dovetail that needs to accommodate movement since if you put a dab in the middle, it will be spread all the way to one end when the parts are put together... Good advice, duly noted. I typically don't apply glue on a sliding dovetail due to the nature of the fit, but this makes sense. Quote Link to comment Share on other sites More sharing options...
rgdaniel Posted December 22, 2014 Author Report Share Posted December 22, 2014 You don't need an account to view Flickr pics. It's a picture of an actual breadboard. (Shaped like a pig, as it turns out). The joints will be about 12 inches across. I expect to glue about the middle third of that, to allow for expansion. But point taken about it sliding and spreading the glue further than intended. The original that I'm copying was a simple T&G (not pegged) and it failed, so I thought I would step up to the sliding dovetail. The one I did five years ago is still holding up fine, best of my knowledge (my sister has it). It was glued all the way across, I think. I was mostly asking about the routing, and whether to pre-hog out the majority of the groove prior to using the dovetail bit. And it sounds like yes, I should. So that's what I'll do. Thanks for the discussion, appreciate it. Quote Link to comment Share on other sites More sharing options...
Eric. Posted December 22, 2014 Report Share Posted December 22, 2014 I was able to view the pics this time...wouldn't let me when I tried before for some reason. I always pre-hog when possible and practical. Less stress on the bit and router, safer and more accurate. No reason not to if it's possible. I still say it's the wrong joint for that piece since you won't be able to glue it...since gluing it would defeat the whole purpose of having a joint that allows for movement. Dollars to donuts...if you had pegged the joint that failed, it wouldn't have failed. It's your piece, though...and I certainly understand and appreciate the impulse to over-complicate things! Quote Link to comment Share on other sites More sharing options...
rgdaniel Posted December 22, 2014 Author Report Share Posted December 22, 2014 I certainly understand and appreciate the impulse to over-complicate things! I am kind of known for over-thinking it... although the ultimate goal is to simplify the execution phase... the piece that failed was just something we had lying around the house since forever, not something I built.... I didn't consider pegging, because of the design... in a board where the design lends itself I might do (and have done) that... e.g. https://www.flickr.com/photos/rgdaniel/3820813653/ Quote Link to comment Share on other sites More sharing options...
Eric. Posted December 22, 2014 Report Share Posted December 22, 2014 Your pegs don't have to go all the way through. You can drill from the bottom and stop short of exiting the top of the board. Quote Link to comment Share on other sites More sharing options...
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