Replies

1. 
   douglas2cats | Apr 14, 2005 01:51pm | #1

   Dont know if it's the fault of your maple, or just an inherent issue with lock miter bits. I've only used one on one project but was also not getting very good results. I was finally able to get good joints by first bevel ripping on the TS, then using the lock miter bit - so that just a very small amount of material had to be removed by the router. 

    

   Waddaya mean it wont fit through the door?

1. 
   jackplane | Apr 14, 2005 04:09pm | #2

   douglas is right, hog out the stock first on the tablesaw as lock mitre bits work best with one clean pass, and use a backing board if you're routing endgrain. 

1. 
   WillGeorge | Apr 14, 2005 07:20pm | #3

   DITTO... I use a lockmiter bit ALOT.. I love it!

   BUT.. As stated.. trim your stock on the TS first and make the final cut with the bit..

   MDF works OK with just the bit... but some woods can be a KILLER using it without trimming first!

1. 
   Dick38 | Apr 15, 2005 04:31pm | #9

   Hi Will,

   What is a miter lock joint?

   Dick38

1. 
   jackiechan | Apr 16, 2005 05:27am | #10

   View ImageDan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

2. 
   UncleDunc | Apr 16, 2005 07:29am | #11

   Here's a pic at a little larger scale.

   View Image

3. 
   Dick38 | Apr 18, 2005 04:06pm | #14

   Hi Uncle Dunc,

   Iv'e never heard of this lock joint before, It looks like it is solid. Thanks for the reply.

   Dick38

2. 
   BertieUK | Apr 15, 2005 12:53pm | #8

   Thanks - good idea. I didn't do that because the general guidance I picked up seemed to say do it all at one pass - and because I hadn't used birds eye maple before, I didn't anticipate how fragile it could be. Another hard lesson in my self tought woodworking journey!

2. 
   troys | Apr 14, 2005 08:15pm | #4

   Do you really need to use a lock joint, will a plain miter joint work. If it is a long piece like a bed post you might have enough glue area to skip the lock joint. There has been some good articles in FNW about how to glue these up. I used those methods for some newel posts and they worked very well. Good luck
   Troy

1. 
   billsams | Apr 15, 2005 01:50am | #5

   As Troy mentioned, they are alternatives to the true lock miter. One I kind of stubbled on is what I will call a "half lock miter".Essentially mitered on the front half but square on the back half, so it's a "mitered butt joint". Simple operation is using a 45 degree birdsmouth router bit, taking small enough passing to elimenate tearout.First miter both pcs half way with birdsmouth bit, then with dado blade on ts, take out excess "even with both edge of 45 miter" on one piece, then slide the fence over and take off the corresponding amount on the second. This operation allows all joints to be cut flat on the table, (no edge cuts with the peice riding in the air against the fences).For some reason this process is hard for me to put to words, but it's real simple, real quick and aligns the pcs while gluing and not much slipping. They is a similar photo of the joint in Tage Frid's Techniques book. His has the extra tongue for the lock, mine doesn't.Hope this was helpful, if not toss it out of your brain.
   Bill

1. 
   billsams | Apr 15, 2005 01:54am | #6

   rereading my message, a section of the 3rd paragraph should read..... "even with bottom edge of 45 miter cut" ,........
   Bill

2. 
   BertieUK | Apr 15, 2005 12:50pm | #7

   Thanks Bill, that sounds really good. As these joints are along the length of the boards I'm not worried about strength/end grain and only chose lock miters because I thought it would help with clamping (which it does) and help lining up (which it also does). I do understand what you mean and as I draw it, the 'butt' part would essentially stop slippage during clamping and help lining up as well - probably with more tolerance than a lock miter. I'll try it next time!

3. 
   TexasJohn | Apr 17, 2005 01:39am | #12

   Bertie,

    

   I have had my locking miter bit for about 3 or 4 years and have used it successfully twice. 

   I can't hardly blame the bit but my cheesy router table.  I recently upgraded to a better router table and hope to use it on my next cedar chest. 

   Glad you posted this thread, because I almost forgot I had a locking miter bit, and everyones feedback will hopefully make my next experience with mine allot less aggrevating.

   Also I remember having a hard time setting mine up ( lots of scrap)  I think I bought some set up blocks.

   Anyway thanks ,

   John

1. 
   kesac | Jun 26, 2005 06:18am | #16

   I quit using lock miters, when biscuit joiners became capable of going to 45°.  Much safer.  Less figuring to make it work.

4. 
   arw01 | Apr 17, 2005 10:43am | #13

   I've found some success with using two pieces of scrap masonite to make initial passes which work like zero clearance inserts. Currently making drawer sides, but the principles are the same.

   The first pass with 1/4" thick masonite just gives me cut across the grain, this limits grain tearout immensley on baltic birch. Second pass with 1/8" thick masonite. Final pass with hard pressure on the board against the fence.

   Alan

5. 
   kesac | Jun 26, 2005 06:15am | #15

   The lock miter is the poorest joint ever designed.  It doesn't even deserve to be called a joint.  It has no good glue surface, and short grain under shear load guaranteeing failure.  Anything is better than that.

   Dowels would be better.  Biscuits would too.  You can get a biscuit cutter for your router fairly cheap.

6. 
   Indigo1557 | Jun 27, 2005 04:10am | #17

   Lock mitres are the spawn of the devil.

1. 
   WillGeorge | Jun 28, 2005 12:33am | #18

   Lock mitres are the spawn of the devil..

   Yes the bit will get a bit HOT on oak.. But.. for case work in 3/4 inch ply I love my whiteside 2 1/2 (I think that is the diameter)....

   On a router table with a HIGH fence and long bed... Pre-cut angle on TS... Cut the profile in the slab using two depth cuts.. BOTH small cuts..

   Have a glue bottle with a roller I cut on a lathe to match the profile....

   I don't do it every day but often enough... Cut panels to 'almost' size.. Cut panels with angle where the bit will be used... Cut lock miter in two passes.. Run glue roller over both edges... All glue profiles....

   Stick together.. four to 8 clamps clamps hold it all together depending on size..

   I have NEVER had a failure in the glue joints... OR worse yet.. Trying to square something and get all the clamps on while holding up all sides at the same time... and the Glue dried up!

   With good ply the joint is really easy to make.. YES.. I have some set-up blocks to set the depth of cut for horizontal and vertical cuts...

   Lock miters sure can make life ALOT easier during glue-up's .. Especially on big cases...

   EDIT:: I work ALONE!

   Edited 6/27/2005 5:34 pm ET by Will George

1. 
   BertieUK | Jun 29, 2005 02:22pm | #19

   I do agree! I started this trail because I had real problems with birds eye maple splitting disastrously. I too work alone and was handling/mitering 6 foot long boards that were very awkward. Despite all the problems I would use lock miters again in this situation (maybe not that timber though!) as the positioning of the joints and clamping is so much easier. Cutting the joint alone on a long length of wide board is awkward and it is easy for the board to move out of line - a further problem - but in my experience the assembly benefits outweigh the cutting difficulties.

1. 
   tjh | Jun 29, 2005 06:24pm | #20

   Patrick Nelson wrote at least one article on using this joint to simulate Stickley-style leg making. It allows a quarter sawn face on all four sides of a leg.  FWW published it in a book on mission style furniture.  He also shows how to make a couple sleds to make control of the wood piece easier.  It's still a bit of a pain - but glue up is pretty easy, and you get to make a lot of noise when you run red oak through the router.

1. 
   WillGeorge | Jun 29, 2005 11:22pm | #22

   and you get to make a lot of noise when you run red oak through the router..

   Try Hickory or purpleheart.....

   I never cut in one pass.. I take a really light cut at first.. See what happens.. A goof is easy to fix if ya got SOME wood left to cut!

2. 
   WillGeorge | Jun 29, 2005 11:20pm | #21

   I had real problems with birds eye maple splitting disastrously.. Ya out to try Purpleheart... That stuff is like a Claymore mine....

    

   and was handling/mitering 6 foot long boards that were very awkward..

   I have one router table that has a really long bed.. Well, the outfeed is 8 feet and in-feed is four feet.. Top is only about 6 inches wide...

   High fence.. Well, about 12 inches.. I use several feather boards.. Ya know.. Them plastic store bought ones to keep the stock firm to the fence... Just a light kiss.. NOT pressing on the wood hard...

   I have ruined a few cuts.. but not many...  in my day...

   By the way.. I have a plum line hanging at the end of the table I look at once in a while to make sure I'm doing OK!