Lock joint bit

Gerry Maul

Member
Messages
19
Location
dunsmuir ca
just picked up a 45 degree lock joint bit, pretty formadable looking. anybody have any luck with them ? any do's or don'ts? thanks Thanks Gerry
 
one of my very favorite cutters. haven't done it on a router table in a long, long time, but i do it on the shaper every chance I get. does take some practice and patience in the beginning. i'll be posting a flats project soon where the lock miter was integral.
 
The key to success, in my opinion, is
  1. For a given setup, all the boards must be identical thickness
  2. First set the height. When you flip one of two test boards over, they will join perfectly if the height is right.
  3. Second, set the fence (for the part that must be aligned against the fence). No matter how great the temptation, don't change the height while you are adjusting the fence. If the height needed changing, you wouldn't have gotten past the previous step.
  4. If you have instructions from an old issue of Fine Woodworking, don't believe it. There was an error in an often-referenced article, that suggested one side of a leg/box/whatever should be done flat, the other against the fence. The better way is both sides against the fence (for two of the four sides) and both sides against the table (for the other two sides)
 
Charlie,

Thanks for your answers. I have read a lot of thread about this bit that were negative. To me it seems like a great bit and I would like to try it someday, so.

I guess I would need to do this to understand, but I don't get # 4....

I'm sure your are correct because 1 - 3 make so much sense, but I am not visualizing # 4.

Thanks...
 
Charlie,

I'm sure your are correct because 1 - 3 make so much sense, but I am not visualizing # 4.

Thanks...

I don't want to speak for Charlie (but I will talk about him if you want to hear some good stories :D - Just kidding.) I think what he means is to cut the two opposing sides the same. For instance, sides 1 and 3 will oppose each other, so cut them both (all four edges) on the table, and then all four edges of sides 2 and 4 on the fence. This makes for a very simplified glue up. I also don't like to set things so that I get a knife sharp edge, which can have a tendency to chip, fray, or worse, cut you. I like to set things so the edge is blunted about 1/64", or there abouts. I also plan on planing the post after glue to my desired dimension (I feel this is easier than trying to get it perfect right from glue up) then the tiny flats I left disappear, leaving what looks like a solid post.

Hope this doesn't confuse the issue.
 
Charlie,

I'm sure your are correct because 1 - 3 make so much sense, but I am not visualizing # 4.

Thanks...

I believe Charlie is saying that instead of producing a "male" on one edge and a "female" on the other for each piece, you can produce two pieces that have both "males" and two that have both "females".
 
Can this bit be used on plywood?

I am planning a 'cupboard' for under my workbench. This looks like it could be useful to make the carcass.


Ian.
 
Hey Gerry,
I really like those bits. Way faster than dovetails. I built some dressers about 15 years ago with miter lock bits. The dressers take a lot of abuse but all the joints have held up perfectly!

My advice is to mill plenty of scrap and make a test box in scrap first. Once you get the hang of it, its easy, but hard to visualize that first time.
 
Another setup consideration that took me a while to figure out for this bit and a few others is the router must be set up so that a bits shaft is 90 degrees to the plate/table surface.
I have a Jessm Mastrlift and it took a little tweeking to get this right.

I have a piece of 1/2" round stock that I put in the collet to check this periodically.
Dan
 
This is so frustrating! Here's the key phrase:

"These joints can not be cut free hand."

And I'm told the same goes for molding. No matter how hard I try by hand, the slight variations in pressure, etc., lead to less than a perfect fit. So what I need is a power feeder. Yeah, ok. That makes sense. So how much is a power feeder? Well, this one's 300:

g4173.jpg


Under the rule "never buy the absolute cheapest one" the next one up is 500. Aargh! :doh:

So, I've got a bit like that, but never even try to use it anymore. It's sitting there collecting dust... just another in the long string of good ideas that didn't quite pan out. The drawer lock bits work well enough for shop drawers, but even those don't make a perfect fit *all the way along the joint*. For a long time, I thought it was just me, messing up as usual. But I think that's why the people who have power feeders love them so much...

Aaargh! ;)

Thanks,

Bill
 
Thanks guys, it will take me some time to assimilate all the information. I haven't got a power feeder and I don't see one in the future. I plan to start on the small side, no big corner joints! If I run into difficulty I'll get back to you. Thanks again Gerry
 
Both Sam and Charles are exactly right (of course). And if you want stories about Sam, just bring scotch, and I'm ready! (Sam prefers single malt, but I prefer large bottles).

It seems funny that any really good article from Fine Woodworking, the posts all seem to say "I can't find it, can you remember where...." But one of their few "mistakes" (what they published would work, but it makes a simple clamp-up hard), it seems that eveyone finds it, and it becomes part of every conversation on lock miters. If you do it like Sam and Charles said, then you only need clamps in one direction, which will pull all four joints together, and hold them square - one of the really neat things about the lock miter.
 
I have been considering getting one of these bits for a while now. Seeing it in practice from the link that Glenn posted, has me sold.

I do have a question, I know that the standard mitre lock bits are usually made for 3/4in thick stock. Does anyone make one for thinner stock, like 1/2in?

Thanks !
 
This is so frustrating! Here's the key phrase:

"These joints can not be cut free hand."

And I'm told the same goes for molding. No matter how hard I try by hand, the slight variations in pressure, etc., lead to less than a perfect fit. So what I need is a power feeder. Yeah, ok. That makes sense. So how much is a power feeder? Well, this one's 300:
Bill

Bill, what they are referring to when they say free hand, means NOT in a Router Table. Now there is still room to mess up:eek: even while using it/them in a router table, "IF" you don't use good Hold Downs located close to the bit, in both the vertical and horizontal direction. If you set them up properly so they will hold the material solidly against the fence and table, you just have to push the workpiece at a steady rate through the cut. To get the best cut, you may have to make a couple or three test passes to determine the proper feed rate for the bit and wood you are using. I think you should try this again and let us know how it works out, I think you'll get the hang of it and be pleased with the results, even without a power feeder. Note: I don't have a power feeder either.:D

One other thing that I failed to mention that will greatly improve the quality of the cut of most (if not all) edge treatment router bits, is to make a zero or near zero clearance cut in the fence on the infeed side by fastening the outfeed end of the fence to the table and with the router turned on, swing the fence into the bit until more than half of the bit is into the fence, then turn the router off and swing the fence back to the desired setting.

Good Luck.
 
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I have been considering getting one of these bits for a while now. Seeing it in practice from the link that Glenn posted, has me sold.

I do have a question, I know that the standard mitre lock bits are usually made for 3/4in thick stock. Does anyone make one for thinner stock, like 1/2in?

Thanks !

I have had good luck with the inexpensive bits/cutters from Woodline.

For the router bits, see www.woodline.com/c-55-45-degree-lock-mitre.aspx. I have the small 1420-2 ($29) but would buy the newer 1420-3 today.

For the "full size" lock miter I have the shaper cutter... www.woodline.com/p-1802-shaper-cutter-45-corner-lock-mitre-34-bore.aspx for $55 (but I thought I paid a little more than that)
 
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This is spooky.

I've just spent the day glueing up and sanding boards to make two bathroom basin units in solid oak which are to have mitred carcasses. I was going to biscuit the mitres but I've just logged on to this thread during my afternoon tea break.

I've never used one of these cutters. Should I order one up for the morning or stick with my biscuits?

Cheers
Duncan
 
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