How to control width of the dado…
March 26, 2010 by admin
Filed under Router Tips
Question from Peter,
Hi Rick and Bob,
I just viewed episode 209 regarding the dado cuts in plywood. You mentioned about the size being ~19mm instead of the typical 3/4″. How do you compensate for that, particularly since the bits are 3/4? I have been using a table saw with an adjustable dado just because of that.
Answer to the question:
In episode 401 we show how to compensate for the different size of material in relation to the size of the router bit. In this case we have material that is 1 – 1/4″ thick and we are using a 1″ router bit to create the dado joint. You will need an offset block 1/4″ thick X the length of your table fence.
Step one: Mark the dado positions on the piece that is going to get the dado cuts.
Step Two: Using the 1/4″ offset block on your fence set the first cut on the closest edge of the dado set up. See the sketch of the first cut.
Step Three: make the first cut, remove the offset block and make the next cut and there you have one cut 1″ wide and the second cut 1/4″ wide.
See the photo of sketch number two showing the final cut to match the width of the dado with the thickness of the material. In our case a 1-1/4″ dado. This makes the total width of the cut for the dado match the thickness of the shelves…For more detail on this operation watch Episode 401.
Hope you guys don’t mind me answering a few questions about how to use the router. Send in your questions and I will try to answer them.
I have a few folks cancel their emails because I added a bit of history to my blog…I guess they felt that I was off topic. I think if they don’t want to be here then canceling is the best option. I figure this is a free thing that I enjoy doing and I should be able to add to this blog with information that I find important…
No I am not going to talk about how sick my cat is but if it is router related and I feel the need to talk about a specific subject then I will be talking about that specific topic.
Again, please send me your questions and I will try to answer all questions. Please note: some I will post and answer and some I will just answer…
I enjoyed your nostalgic posts. I’m sure a lot of us may take powered routers for granted, but occasionally we need to be reminded that many hand held power tolls are relatively recent arrivals on the woodworking scene. Also, early hand held power tools were often large, heavy, underpowered, and with few options or accessories compared to those available today.
Thanks for sharing your experiences and keeping us informed of ALL things router related.
BTW: I wouldn’t mind hearing about your cat’s successful woodworking projects as well.
i like too install a starter pin on my router table from shaper bit. what size pin i need and the location on the table and distance from router bit????
What size is the shaper bit? I also assume the shaper bit has a pilot bearing…can you give me a bit more information?
Rick
I like hearing a little history. Maybe some folks think that they know everything already and will not benefit hearing about past knowledge. (how stupid they are). How about adding a little more history in your blog, for us, who appreciate experienced workers who are willing to share past experiences.
To all that are interested:
Sure, Dad is back from the warm weather around the first of the month. I am looking to conduct a series of interviews with him and want to feature one of the constructed router jig in each of his interviews. I was going to ask some questions and let him answer. There is a lot information that is still untapped. He has had a passion for the router for approx. 60 years, he has created 183 episodes for TV and has designed very ingenious jigs and fixtures. That is a very long time with a deep passion for the uses of the router…
Some of the most common fixtures that everyone know about is the base plate for the Table mounted router. His first base plate come out in early 1978 and yes he was the first base plate.
With this come first router book in 1979. He hurt his back and couldn’t do anything but think about “the Router” It took him three days to write the book and it has been a best seller for many years…
I think we have a lot to talk about…thanks for the encouragement
Rick
on English dimensioned plywood the three quarter pw is usually one thirtysecond under You can buy router bits that have the correct width perhaps the metric pw has a similar set of bits
john stark
For any dado with plywood, just use an undersized bit. You never know exactly what your plywood will measure in thickness until you actually measure it. Whether using a dado or a router, just set up for an undersized cut, and make two passes to get the final width. You can get an exact fit this way.
OR, cut an undersized dado, and rabbet the edge of the plywood to fit into the resulting slot! Makes for a better looking and stronger joint that way.
Keep the history lessons coming! I can’t believe how the products came out in those days with what they had. Also I think it’s cool to see tools of way back then.
THANKS
As an octogenarian who has followed and admired your father’s skill (and yours) and inventiveness for many years, I am interested in subscribing to your weekly series. What has deterred me is the storage of your info so that I can access it as my time permits. Would it be available on a CD? Would there be any objection to my recording it in any fashion, if I am able,for my sole personal use?
So you want me to offer the low res video on a CD and not on the Internet. Cost might be a problem $190 bucks. The video on the Internet is offered 24 hours per day 7 days a week at $4.00 bucks a month. You can watch when ever you want to watch. Hopefully I answer your questions, Rick
I agree with all on the subject of getting the dado width right. There are several ways to do it. Above are listed just a few good ones. Aword of advice never start without having the plywood that will go into the dado on hand. As sure as we are here talking about the reduction of thicknesses someone will yet again be thinking of changing dimensions. We will always need tricks of the trade to overcome odd dimensions.
As to history or any other router related topic is OK. We all want to learn as much as possible. Especially from the experts.