Hi, new here and to woodworking. Can’t believe all the info on this sight, absolutely amazing.
My question: Is it possible to dovetail a miter joint? In my research here I’ve seen a few dovetail joints that were mitered the last inch but it doesn’t look as though it involves the dovetail itself.
I ask because most of the work I’m doing is octagonal. Anywhere from 3″ tall to 36″ tall. I really don’t like those long miter joints. I’m currently using a loc-miter bit for some added glue surface, but is there something better?
Thanks
Trevor
Replies
trev,
octagonal as in 8-sided,stave constructed, tube-like affairs? i cannot get a visual on a dovetailed miter, and, as i am currently understanding your query, i do not think it can be done. perhaps you are referring to a full blind dovetail?
anyhow, welcome.
eef
I'm officially miter bit challenged, LOL. I usually just spline mitered joints when just gluing is not enough. You can either spline along the joint (where the spline is invisible except at the end grain) or across, where the splines show up on the surface - can be pretty cool looking.
You can also use full blind dovetails on miters, but you'd need something higher-end than a basic DT jig (maybe a WoodRat - dunno, never tried it this way), or do them by hand. Dunno how well this would work on an octogon, though -- not much relief to work with due to the high obtuse angle.
Mike Hennessy
Pittsburgh, PA
Everything fits, until you put glue on it.
It's certainly possible to dovetail a 45-degree joint, but it would be very challenging to figure out the angles for the cuts.
-Steve
Look here about 28 mins in.
http://www.woodrat.com/dvd.html
Thanks. It can be done with the woodrat or the other one that's just like it. How about a shop made jig? Hhhmmmm....
I think anything that can be done on a 'rat can be jigged up on a router table.
Doesn't the issue boil down to some trade-off between joint strength and convenience? The required joint strength, it would seem to me, is a matter of the direction of forces the piece is undergoing, along with the amount of force. The splined miter and the 22 1/2° lock miter bits you are using now add both registration/alignment benefits along with added strength against tangential forces - forces at some angle to the length of the miter. With an octagonal column, which I assume is what you are building, most of the forces encountered would be in line with the joint, I'd think, and usually fairly equal around the perimeter of the octagon. The extreme might be a force of such magnitude that it might cause the individual segments of the octagonal column to bow out, causing the glue joint to fail.So, I guess the questions are what sort of forces are you trying to design for, and how does convenience of build fit with that?
You are correct about the column. Not sure how much I need to build into them. I'm a taxidermist, and I'm building these as pedestals for deer and such. An octagon with a 16" width both ways would only be supporting 20-25 lbs on top.
Convenience is a concern. I make a decent penny on the woodwork but I still can't spend a ton of time on one. If it takes me more time to build a pedestal than it does to mount a deer, I'm going to be upside down.
At the time, I'm still learning, it takes me longer than it should. But, I know as I develop my skills/process/work flow the time will shrink.
The stiles are generally 2" wide if that makes any difference with the forces involved. My rails vary depending on height.
Thanks for all the info.
"The stiles are generally 2" wide if that makes any difference with the forces involved. My rails vary depending on height. "Now, I'm confused. On a panel door frame, the stile is the vertical member and the rail is the horizontal one (like the rails in a wooden fence). Are you referring to base segments as "rails"? And, how is the mounted deer attached to the column? (Can you upload a photo?)My guess would be that an octagonal column with 2" segments would support several hundred pounds (excluding tip-over considerations), unless made of 1/4" Balsa wood.
Edited 5/16/2009 5:59 pm by RalphBarker
Stiles are almost always 2" wide 3/4 thick and the lenght varies by height. The height of the rails varies by height as well. The tall pedestals get a "taller" rail.
I'm going to try and attach a pic of a short ped. This is 12" tall.
Ah, now it's clear from your photo. I was envisioning a narrow, or small-diameter column, composed of only vertical segments. For this sort of structure, I think the 22 1/2° lock miter bits you are using now provide plenty of strength on the corners of the octagon. Are the rails joined by M&T joints? Also, is the pedestal weighted in some way? From the photo, it looks a little tippy.
bow,the 221/2degree or a 45 deg. edge miter on the stiles in your photo do not need anything more than edge gluing. it is long grain to long grain and therefore very strong. i clamp that sort of thing using a strap clamp. i have done it many times and it makes for a strong joint.
eef
I think the long grain joint would have more strength than dovetails cut in the long edges of the stiles. You'd be introducing end grain gluing by using dovetails. Instead I would consider using a birdsmouth router bit and cut one edge of each pair of stiles. You could do it with a V-groove bit or even a table saw but the birdsmouth bit would allow the work to lay flat on the table. You would get slightly more gluing surface and it would be much easier to clamp up when gluing than a simple beveled edge.
Thanks for the last two tips about the long grain. I would not have figured that the long grain joint would be that strong. I guess I'll save myself some time and just stick with the lock miter joint I've been using.
I do appreciate everybody's response.
I saw a machine on the boob tube (TV) that cuts a dovetail in both pieces in the center of the mitre joint into which is inserted a dovetail key (like a butterfly key) to lock the pieces together. The pieces were laid flat on a table/fence arrangement and the dovetail bit is drawn up through each piece.
Don't recall the make of the machine but I should think one could make a jig/fixture to do the same thing on a router table/fence setup.
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Bob,
Is this what your thinking of?
http://www.hoffmann-usa.com/index.htmThey make the keys out of everything. Big use in assembling and squaring a lot of wall trim/wainscoting etc. Used on back side( not to mention miters ;)Boiler
Boiler,
Yup that looks like the one. Not to expensive, eh!? Maybe Santa..... Yeh right. They were demoing cutting on miter joints when I saw it and the keys were quite visible. Not sure if that would be an issue.
I should think one could do the same with the Incra. Actually a sled type of jib/fixture on a router table?
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Bob,
........I didn't say it wasn't expensive, especially for a retired N'or Easter. It does cost some bucks but it's fun...in the same way the LV mighty mouse scraper is. Why? You thinkin of taking up finishing work?Take care and get those tomatoes planted or the horses won't like it.
PS I think you can even get brass keys! Buy the way, on the wainscoting etc the keys are installed on the backside.Boiler
I agree that simply gluing long grain to long grain is plenty strong enough. I made a bed with octagonal legs and just glued them up and they easily held the weight of the mattresses and person sleeping.Jim
Finger / box joints would be very strong, and not that hard to do.
I like to use a TS sled for cutting the fingers. Your fence would need to slope at 45º, otherwise everything is normal.
YOu can dovetail a miter, but it becomes a blind dovetail. They are known as super secert mitered dovetails. Basically they are like half blinds except you have to cut both side half blind. So in the end all you see is the miter itself. And once glued up no one will ever know you have them in there. They will have to take your word for it.
http://www.kalafinefurniture.blogspot.com
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