# biscuit joint on door frames?



## sawdustman (Jan 23, 2010)

I am making an entertainment center and am thinking of using biscuit joints on the glass door frames. Would there be a problem with that? 

thanks for your input.


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## bb71 (Jan 23, 2010)

I've been doing that for years. I've had one failure (slight separation not falling apart) and it was because of starving the joint when gluing. The joint also had only one biscuit. Ensure the joint has plenty of glue. I also double biscuit (2 x #0 biscuits) each joint. I typically use 7/8" thick stock for rail / stile doors so that give an extra bit of space for the double biscuit. I use original Titebond usually.


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## cabinetman (Jul 5, 2007)

sawdustman said:


> I am making an entertainment center and am thinking of using biscuit joints on the glass door frames. Would there be a problem with that?
> 
> thanks for your input.



If you are planning either a butt joint or a miter, I wouldn't use biscuits. For a butt joint I would use a half lap joint, and for a mitered joint I would use half lap miters.


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## woodnthings (Jan 24, 2009)

*Or a splined miter*

Like this:
http://www.woodworkingtalk.com/members/woodnthings-7194/albums/kitchen-cabinets/

Or a half lap like this:


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## cabinetman (Jul 5, 2007)

woodnthings said:


> Like this:
> http://www.woodworkingtalk.com/members/woodnthings-7194/albums/kitchen-cabinets/
> 
> Or a half lap like this:



There's a few problems with machining the frames which captivates the glass. They are a PITA. In doing any finishing it would require handling with the glass, taping, and cleaning. Next would be to replace in case of damage. 

Rabbeting the back of the frame solves those problems.


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## woodnthings (Jan 24, 2009)

*Yup that's the way I did it*

Can't tell from the photos though. Point well taken. I made small "L" brackets to retain the glass and used foam cushions to soften the closure impact. I don't want to ever repair those glass panels...IYKWIM.
:no: 
new photo of splined miter and for anyone interested I made them on the RAS with the blade rotated horizontal to the table and a jig to hold the frame members. I still have the jig just in case.....:blink: bill
BTW I don't like biscuits unless they're soaked in honey along with black coffee...


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## bb71 (Jan 23, 2010)

Take a look at Fine Woodworking #111 (pg 58). There is an article on joint testing they performed in door joints. According to their testing, two biscuits outperformed a mortise and tenon. Only slightly, but still better. Considerably better than dowels or tongue and groove.

They're good for more than just dunking in your coffee.


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## woodnthings (Jan 24, 2009)

*Joint strength test link*

http://www.finewoodworking.com/ToolGuide/ToolGuidePDF.aspx?id=31926

the video:http://www.finewoodworking.com/skillsandtechniques/skillsandtechniquesarticle.aspx?id=32281


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## bb71 (Jan 23, 2010)

Thanks for pointing out the newer testing. Interesting they didn't test the double biscuit joint like they did last time. The single biscuit fails at 545 lbs in the new test but according to the older testing, a double biscuit failed at 2800 lbs. I wish they had included the double biscuit in the newer testing.

One thing not to overlook that they point out in the article, most of these joints are more than strong enough for a door frame application. Even the cope and stick joint which performed second to last is fine in most applications.


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## jlhaslip (Jan 16, 2010)

To secure the glass into the door, lay the door face down, place the glass into the rabbet and a bead of silicone around the outer edge of the glazing will keep it there.


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## GeorgeC (Jul 30, 2008)

bb71 said:


> Take a look at Fine Woodworking #111 (pg 58). There is an article on joint testing they performed in door joints. According to their testing, two biscuits outperformed a mortise and tenon. Only slightly, but still better. Considerably better than dowels or tongue and groove.
> 
> They're good for more than just dunking in your coffee.


I thought that is was doughnuts that were dunked.

This is an age old debate about which joint to use that continues on this discussion group and all others across the world. It will go down in history along withthe one about the chickin and the egg.

Actually the simple answer is probably that the best joint is the one that the individual is most comfortable in making. If he/she is comfortable with making a specific type of joint, then they will probably do the best job making that joint.

George


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## RLFX (Feb 2, 2010)

cut your 45 biscuit flip her over put another in good to go..


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## sawdustman (Jan 23, 2010)

*Have Decided*

Thanks to all of you who took time to reply. Your input was very helpful. I have decided to go with double biscuits for now as I have the most confidence in that joint and it is rather simple to make with my porter Cable joiner. Later, I am going to attempt other joinery to expand my options on future projects. :yes:


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## seanmacdougal (Feb 5, 2010)

Just a minor point which was spurred by the photo of the mitered door. Rail stile joints in doors are typically done to appear as a butt joint. According to my deep-seated prejudices, only a moulded part should be considered for mitering. Flat stock would be joined, by whatever means, to appear butted. You would need smaller biscuits for this perhaps, but it would produce a fair strong joint over the short and probably medium term. I possess a number of very old pieces of furniture (all 240 years old or more) and I never seen a door on something this old that was not tenoned AND pinned. The glue on these failed centuries ago, yet those doors are as tight as they day they were made. The glue on our work, modern and strong, will eventually fail in cross grain mortise and tenon constructions. I see it in my older work. 
Anyway, the biscuit will produce a very strong joint. The point someone made about the failure tests is valid only to a point. These tests employ far too high a strain rate to tell us about long term joint failure due to movement. I build to last forever, and with that outlook, the only joint that will answer is the pinned mortise and tenon.


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