I’m building a bed from Jeff Miller’s book, “Beds.”
The bed has thirty-three 29 inch long slats at the headboard end and thrity-three 12″ long slats at the Footboard end. The slats are 7/8″ square. Each slat has a 1/2″ by 1/2″ tenon on each end.
The Tenons are housed in “Constructed” mortises.
You groove the pieces which receive the slats. (It’s that job about which this letter is being written)
You fit a long “dentil” strip of wood into the 1/2″ x 1/2″ groove. You then remove the “dentil” strip and cut notches in the dentil strip to house the tenons of the slats. The dentil strip goes back in its groove and you fit the slats, etc., etc.
So——
I need to run a Dado 1/2″ wide and 1/2″ deep along one long edge of
two Poplar boards which are approximately 63 inches long and 6″ wide and 1 1/8″ thick.
Later, I’ll have to run the same size groove in one edge of two Poplar boards which are 63 inches long by 2″ wide and 1 1/8″ thick.
I don’t know how to set up my Unisaw for such a long groove in a fairly big board. How can I set up my Unisaw for such Dado cuts?
Screw a long auxiliary fence to the tablesaw fence?
How can I hold the board to be grooved down on the tablesaw (It’s a Unisaw) while passing it over the Dado head?
Any special way to hold the long board to be grooved against the fence so it won’t try to wobble around while going through the Dado blades?
Is it safe to cut the full 1/2″ depth of the dado in one pass or should I do it in two or three passes?
I have used the Freud Dado head a number of times over the years but never got into a project that called for a long Dado in a fairly long, thick, wide board.
All advice is really appreciated.
WilliamHF
Florida
Replies
WilliamHF ,
First off imo you need to select the stock to be dadoed for flatness and they need to be straight as possible .As always there is more than one way to do things , you could use a slot cutting router bit that cuts a 1/4" X 1/2" slot by running it from each side to create the 1/2" slot or simply run them over your table saw with your standard fence and a slow rate of feed .
hope this helps dusty
I could use a router to make the 1/2" wide groove a half inch deep, making maybe three passes, I agree. But I want to do it using the Dado cutterhead if I can rig the work so that I feel the cut is safe.It seems to me there would be significant kick back of the 63" long, 6" wide, 1 1/8" thick board when it meets the Dado cutters.Wrong?Do you think taking only a quarter inch deep cut with each pass and passing it over the dado cutters twice would be the best way to go?Or do you think taking the full 1/2" deep cut is not overload?Would you use only a featherboard to hold the work against the fence?I would appreciate it if you or other Knots readers would expand on your reply.Thank you,WilliamHF
FLI make something, sometimes twice, each year.
WilliamHF ,
Typically kickback will occur when the material binds between the blade and fence or other similar scenarios . There will be no real tendency for kickback with the cut you will make . If you have a 3 hp TS one slow pass should do it , take 2 passes if you feel more safe doing so . I would try and use stock that is straight and flat if possible , and most likely not use a feather board at all . As I feed the stock I push down , forward and against the fence all at the same time . Your confidence will come with actual experience and hands on doing .Safety is paramount at all times and with all operations , if it does not feel right ,STOP immediately , re group and think it over .
good luck dusty
If you have a nomal sized outfeed table there should be no problem. If not, use out feed supports. The length of your fence should be fine. I've performed similar operations in much longer boards. Just support the stock well (in and out feed) then maintain pressure near the cutter and do it in a couple of passes.
Mike
Mike said,
"If you have a normal sized outfeed table there should be no problem. If not, use out feed supports. The length of your fence should be fine. I've performed similar operations in much longer boards. Just support the stock well (in and out feed) then maintain pressure near the cutter and do it in a couple of passes".Mike, please expand a little on your reply---for which I thank you and "notDusty."I use a Rockwell 10" tablesaw with Freud 8" Dado cutters. The fence is an Excalibur. I have two roller stand outfeed supports but no outfeed tables.I have the impression, not based on experience, that passing a 63" long, 6" wide, 1 1/8" thick board over a 1/2" wide Dado cutter blade set, and taking the full 1/2" depth the groove needs to be---I'm suspicious that there would be quite a kickback when the board enters the cutters. Am I wrong about that?If I reach the 1/2" depth by taking several passes, I feel sure the
width of the groove will vary at least some from the desired 1/2" which the Dado blades are set up for. What do you think?Does anyone ever build a special L-shaped auxiliary fence for such a job? The auxiliary fence would be as high as the 6" board and a cross piece
fixed to the auxiliary fence would just clear the top of the stock and serve to hold the board down on the tablesaw's table.Would you use a featherboard to press the stock against the fence--in the usual way? Or would you suggest some other way to hold the stock
snugly against the fence?Any other ideas about how to make this a "safe" cut will be appreciated.Many thanks for any further suggestions.WilliamHF
FLI make something, sometimes twice, each year.
William
If you are worried about bogging the blade in a 1/2" wide rip, try reducing the width of the cut, rather than the depth, to say a tad over 1/4" & running the board thru twice. (You may be able to set the fence up so that the board is just reversed for the second rip.)I'd also be inclined to groove the board before final dimensioning to enable removal of any tear out on the (bottom) edge of the cut.
Don
The operation you are wanting to do is not a dangerous one. I thing that it is a lot safer than ripping large plywood parts or narrow stock. It sounds like you are anxious about using the Dado head. This is understandable, a dado head makes a menacing sound when spinning on a Big saw. Taking multiple passes (I think two is plenty) will be signifigantly safer, and less likely to burn. If your saw is reasonably well tuned up multiple passes should make as good of a Dado as one pass. I certiantly think that due to the size of the work piece (although it is really not that big) the dado is a better option than a router. "Kick back" is very rare when making dado cuts. Kick back generally occurs when you are ripping and the board closes shut on the back side of the blade causing it to bind, then launch. In a dado operation the kerf can not reasonably close on the blade because the cut dosent pass through, this is also why a splitter is not necessary. The weight of the work piece (shounds like it must weigh 15 or so pounds) will be an advantage. THe weight will help keep the piece on the table.
If the idea of cutting this dado on the saw is too unerving, don't do it. Being nervous and timid will increase you chances of making a mistake. Do you have a more experienced friend who can help you? Some times having someone with you who has done it before makes a big difference.
I'm am not shure what to elaborate on in respect to the sentences you quoted. On a cabinet saw outfeed tables are the norm. It is a table that is coplaner to the saw table and imediately behind the saw. Most people make them long enough so that you can rip an 8 foot long board without using additional support behind the table. that comes out to around 48 inches. Outfeed supports look like this http://www.amazon.com/gp/product/B00002263O/103-5507488-2370252?v=glance&n=228013&%5Fencoding=UTF8&v=glance . Although I prefer the type that dosen't use a roller. Ridgid makes a great one. If you do not have a outfeed table then you set up one of these outfeed supports maybe 3 feet behind the saw, then if you are really concerned about it place another one about 2 feet in front of the saw. By "maintaining pressure at near the cutter" I mean that you should try to push down on the stock as it passes over the cutter (but don't put your hands directly over it). This will keep the stock from ridding up the blade.
Again I think that you might want to find a member of this forum, or some other friend to show you what to do. A general rule about using machinery is that if the operation dosent "feel safe" then don't do it. And what feels safe to some dosen't to others. Some people think that Dado blades in general are unsafe, while at the other end of the spectrum people rip lumber with no blade gaurd or splitter. If you are timid around a machine it will get you.
Mike
Thank you, Mike and the other gentlemen who kindly replied here with helpful comments.Presumably because I'm getting older now and have become more timid than formerly that makes me apprehensive about this unfamiliar Dado cut.After reviewing everything that was posted to me, I set up the old Rockwell Unisaw with a roller support on the infeed side of the saw and another one on the outfeed side of the saw.I clamped a big featherboard against the stock just before it entered the blade.Needless to say I carefully centered the stock on the Dado head's blades and locked the Fence into proper position. I did not use any auxiliary fence, just the bare naked Excalibur.I found setting the right depth of cut was by the trial and error and "sneaking up on it" methods. I laid a piece of good quality 1/2" thick plywood on the table next to the Dado blades and eyeballed the highest point of the blades against the 1/2" thick plywood. I had some scrap cut offs of the same stock I was about to run the dado groove in so I made a couple test passes on the scrap about a foot long to arrive at the final 1/2" depth of cut. With Fence locked down at the right place, with Kill Switch readily reachable with foot or push stick, I started the stock through the Dado cutters, helping the featherboard with the right hand and pressing down on the stock with the other hand and slowly passed the 63+ inch long 6" wide 1 1/8" thick board completely through the saw and out the other side without incident. The Dado set's cutters are carbide tipped and quite sharp still and the cut went smoothly. I could sense that all was well by the smooth vibrations I felt with the pushing hand and with the other, left, hand which I pressed down on the stock with a pressing component also keeping the stock against the fence on the outfeed side of the cutters. There wasn't the slightest hint of the stock traveling out of line.Feeling better about the whole deal, I ran the other boards requiring the same groove through the setup without any trouble.I learned something thanks to you generous Knots advisers and teachers.I'm sure it's hard to believe that I have any experience at all----anyway, I've been doing saw work for at least 40 years. But in the recent two-three years I haven't made much furniture, etc. I'm 77 now and I'm slowing down.Now I'll crawl back in my hole.Thanks, Guys.WilliamHF
FloridaI make something, sometimes twice, each year.
I would encourage you to find a woodworkers club in your area. It is nice not to have to learn all this alone. I was "lucky" I grew up in a family of carpinters and woodworkers.
Mike
Now I'll crawl back in my hole.LOL... LOL..Mine has a WELCOME mat I use it so much.....Glad it all worked out for you!
A little different approach.
I one had to put a 1/4" spline in the edge of 2 pieces of 1" plywood 5' long to be glued together for a bench sub top. I used my biscuit joiner & set it to plunge to the depth I wanted & adjusted it to take 1/2 the width needed & then ran it along the edge one pass & flipped the plywood over & ran it along the edge for the second pass. I think this would work well for this application too. I wasn't 5 minutes setting things up & another 5 minutes per piece of plywood running the groove.
It was a real easy operation.
WilliamHF,
I am with notDusty. I work with large stock on a Unisaw with Unifence farily often. As for the dado at 1/2 x 1/2, just feed it slow, and you should have no problems. I have cut deep/wide dados without a problem, just take a slow feed and keep a firm grip on the board. If you have them, the non reversable roller hold downs installed both fore and aft of the blade will give further control. I recommend an out feed table or roller to support the end to you are not having to counteract gravity while feeding the board.
Try a test on a piece of 2x6 to get the feel of it. They are not free, but a lot less expensive than the poplar.
Elbert
A dado 1/2" deep by 1/2" wide is not a problem, especially in poplar. I do similar dadoes in hardwoods frequently with no problem. You will not experience "kickback" simply from making the cut, unless you do the sorts of things that would produce kickback in typical sawing, e.g. pinching the stock, failing to hold the stock down against the table at the rear of the blade, etc. Also, in my experience, the bigger the board, the less likely kickback will be since the mass of the piece helps to control it. Bigger stock usually just bogs down the blade rather than becoming ballistic. The length of your cut will not be a problem if you use outfeed support. Yes, using a featherboard is always a good idea -- it holds the stock against the fence so your dado stays straight and it helps prevent kickback.
Now, that said, I've done lots of crafstman-style pieces with slats as you suggest. The dado is the easy part. The dentil strip (named after dentil molding - kind of like a comb with fat teeth) is a bit tougher. When I do this, I usually make my dado 3/4" deep and cut the dentil with a modified box joint jig on the table saw. This lets me make the "grove" 3/8" deep and still have 3/8" of sticking at the bottom holding the thing together. Makes it easier to put together later. The tough part is making 30 or so dentils equally spaced over a long span. Lots of trial and error with the jig and tearout can be a problem. (I usually start with a thicker piece to make the dentil and then rip it to thickness after it's made.) Otherwise, you can just measure and cut freehand without the jig. Works OK, just not as accurate -- but not off enough that anyone (besides the builder!) would notice.
Mike Hennessy
Thanks very much Mike Hennessy for your response. Very helpful.
You obviously have done many of the very type of Dado cuts which I wish to make. Your experience is much appreciated.Your experience re the dentil strip helps too.Now pleaseclue me in on this last question which your reply prompts me to ask:How do you "hold the stock down against the table at the rear of the blade?"Thanks again, Mike.WilliamHF
FLI make something, sometimes twice, each year.
Outfeed support helps. (It will help keeps the weight of the wood from levering the last part of the cut up off the table.) Keeping downward pressure on your push stick at the end of the cut helps as well. Again, normal safety procedures will suffice for this cut. You might want to check out some of the books on using table saws that are availble to make sure you understand safe operation of this machine. I'm sure the ones available from Taunton will be great.
Good luck on this project. Sounds like fun.
Mike Hennessy
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