Pocket vs. M&T
 

Pocket screw setups look much easier than mortise & tennon and,
apparently, are just as strong. Unless a through tennon extending
beyond the rail is required for structural or decorative reasons, are
the two systems actually interchangable?

FoggyTown

foggytown Feb 18, 6:38 am show options


"From: "foggytown" - Find messages by this author
Date: 18 Feb 2005 06:38:12 -0800

Pocket screw setups look much easier than mortise & tennon and,
apparently, are just as strong. Unless a through tennon extending
beyond the rail is required for structural or decorative reasons, are
the two systems actually interchangable?"

No. Pocket holes work extremely well in some instances, such as face
frames, but are close to dead worthless in others. For example, I'd
never use pocket holes to attach legs to a table apron when that table
is going to get any heavy use. For headboards and footboards of beds,
M&T is much more secure. I like pocket holes for face frames, but don't
use them for much else.

"foggytown" wrote in message
oups.com...
Pocket screw setups look much easier than mortise & tennon and,
apparently, are just as strong. Unless a through tennon extending
beyond the rail is required for structural or decorative reasons, are
the two systems actually interchangable?

Short answer: No.

My gut says that M&T will be considerably stronger, but PH is plenty strong
enough for all but the very most demanding applications.

IMHO pocket holes look like sh*t.

If you aesthetics matter *and* the joint shows, skit PH and use M&T

Otherwise PH is fast and effective.

Exception: IMHO, PH does not belong in heirloom quality construction,
because "style" counts even where you can't see it.

I love pocket screws and use them where ever I can.

But don't forget they are a mechanical fastener. If you aren't able to get
several in over a reasonable length, anything subjected to torque will
gradually move more and more, until you have failure.
I have used them where there was room only for one screw, but only when no
torque was possible; like a divider in a very rigid frame.

Just for emphasis, I agree completely with Charlie and toller. Pocket
holes aren't as strong, durable, or attractive as mortise and tenon
joints.

foggytown wrote:
Pocket screw setups look much easier than mortise & tennon and,
apparently, are just as strong. Unless a through tennon extending
beyond the rail is required for structural or decorative reasons, are
the two systems actually interchangable?

FoggyTown

"foggytown" wrote in message
Pocket screw setups look much easier than mortise & tennon and,
apparently, are just as strong. Unless a through tennon extending
beyond the rail is required for structural or decorative reasons, are
the two systems actually interchangable?

For the *right* application, PH joinery can be hard to beat. However, and
for my way of working and what I make, that "right" application is almost
exclusively limited to face frame construction.

--
www.e-woodshop.net
Last update: 11/06/04

Well... PH's are not as strong as M&T, I agree they are ugly and they
are not a good replacement for all M&T but my experience says they are
not as bad as some portray.

Look at http://www.sonomaproducts.com/Furniture/JL-ET-RO.htm

It uses pocket screw joints for all the upper aprons, pockets under the
shelf and one screw up at an angle from under the lower spreaders arch
up into each leg. Combined with dowles in the pickets and the top
attached with table buttons this unit forms one hell of a strong frame.

I have proof of this, one that I shipped was destroyed by a FedEx
Ground contractor. It was eventually returned with fork lift tire marks
on the box. The top was broken from the unit, two pickets were
completly dislodged and the frame was still solid and stands on all
four legs as flat as when I shipped it. I intend to repair it someday.

Would M&T be stronger? Yes. In fact I plan on building a set of this
line for my home and I'll be using M&T, but pocket screws can save time
and provide a strong joint.

I also use them occasionally on solid wood case work, table
legs-to-aprons (with added transvers braces), etc. and have not had any
problems. On occasion I'll add longer screws if using a soft wood or
landing in an over-running panel dado.

On 18 Feb 2005 06:38:12 -0800, "foggytown" wrote:

Pocket screw setups look much easier than mortise & tennon and,
apparently, are just as strong. Unless a through tennon extending
beyond the rail is required for structural or decorative reasons, are
the two systems actually interchangable?

FoggyTown


no.


pocket screws leave butt ugly holes. fine for hidden locations and
rough and ready shop furniture.

pocket screws are strong in one direction, weak in the other. M&T are
strong both ways.

there is really very little overlap in application.

On Fri, 18 Feb 2005 10:12:46 -0500, "Stephen M"
wrote:


Exception: IMHO, PH does not belong in heirloom quality construction,
because "style" counts even where you can't see it.



that's a little too broad a statement. get underneath some really nice
100 year old furniture and you'll see pocket screws holding cleats and
the like in place.

Exception: IMHO, PH does not belong in heirloom quality construction,
because "style" counts even where you can't see it.



that's a little too broad a statement. get underneath some really nice
100 year old furniture and you'll see pocket screws holding cleats and
the like in place.

Point well made. Hoever, the pocket holes used in quality antiques were made
with big-ole honk'n screws with 1/4" shanks on them. Although it is a screw
in a pocket, they are nothing like the "the kreg system".

Which, BTW, is not a slam at the Kreg system, I think mine is great, it's
just like comparing a Honda Civic (had one of those and loved it too) to a
Hummer.

Swingman wrote:

For the *right* application, PH joinery can be hard to beat. However, and
for my way of working and what I make, that "right" application is almost
exclusively limited to face frame construction.


For me, add shop jig construction to the face frame work. I've also
started to use pocket holes more than biscuits for finish (trim) work.

Furniture gets more traditional joinery.

Barry

On 18 Feb 2005 06:38:12 -0800, "foggytown" wrote:

Pocket screw setups look much easier than mortise & tennon and,
apparently, are just as strong. Unless a through tennon extending
beyond the rail is required for structural or decorative reasons, are
the two systems actually interchangable?

FoggyTown


Pocket screw joints are strong but I would not use them for
everything. The primary advantage of pocket screw joinery is speed
of construction. Personally, I would not use pocket screws in fine
furniture and find the oval holes plain ugly. A mortise and tenon
joint is load bearing, handles compression well, resists tension and
racking, and still holds up well after years of abuse. A M&T joint
usually gives a warning before failure, unlike most other joints. I
don't have any studies showing the pocket screw is just as good as the
M&T, but I'd be interested in learning more about this. Many
woodworkers shy away from metal fasteners, only using them as a last
resort.

On Fri, 18 Feb 2005 14:23:56 -0500, Stephen M wrote:

Which, BTW, is not a slam at the Kreg system, I think mine is great, it's
just like comparing a Honda Civic (had one of those and loved it too) to a
Hummer.

Yes, I'd say something that's well made and efficient, compared to
something that's oversized and unnecessary, is a valid comparison ;)

Love my Kreg jig too, but there's times for doing it other ways.

On Fri, 18 Feb 2005 14:23:56 -0500, "Stephen M"
wrote:

Exception: IMHO, PH does not belong in heirloom quality construction,
because "style" counts even where you can't see it.



that's a little too broad a statement. get underneath some really nice
100 year old furniture and you'll see pocket screws holding cleats and
the like in place.

Point well made. Hoever, the pocket holes used in quality antiques were made
with big-ole honk'n screws with 1/4" shanks on them. Although it is a screw
in a pocket, they are nothing like the "the kreg system".

Which, BTW, is not a slam at the Kreg system, I think mine is great, it's
just like comparing a Honda Civic (had one of those and loved it too) to a
Hummer.





not meaning to be in a flame war or to be too picky about language or
whatever, but I guess that:

Exception: IMHO, PH does not belong in heirloom quality construction,
because "style" counts even where you can't see it.

should have been:

***Exception: IMHO, Kreg screws do not belong in heirloom quality
construction,
***because "style" counts even where you can't see it.


I think we are really in agreement.

Dave Hinz wrote:
On Fri, 18 Feb 2005 14:23:56 -0500, Stephen M
wrote:

Which, BTW, is not a slam at the Kreg system, I think mine is
great, it's
just like comparing a Honda Civic (had one of those and loved it
too) to a
Hummer.

Yes, I'd say something that's well made and efficient, compared to
something that's oversized and unnecessary, is a valid comparison ;)

Reminds me of my favorite news group signature

"Get rid of the Range Rover. You are not responsible for patrolling
Australia's Dingo Barrier Fence, nor do you work the Savannah,
capturing and tagging wildebeests."
--Michael J. Nelson

I guess at the end of the day a pocket hole joint is nothing more than
a reinforced butt joint and, if well done, shouldn't look any different
to an M&T. The strength of the joint is another matter and I'm not
competent to comment on that. Any structural engineers in here? :)

FoggyTown

"toller" wrote in message
...
I love pocket screws and use them where ever I can.

But don't forget they are a mechanical fastener.

As opposed to M&T that is non mechanical?

"foggytown" wrote in message
oups.com...
I guess at the end of the day a pocket hole joint is nothing more than
a reinforced butt joint and, if well done, shouldn't look any different
to an M&T. The strength of the joint is another matter and I'm not
competent to comment on that. Any structural engineers in here? :)

-----------------
I have a Trend PH jig and use it quite a bit. It's quick and easy but not
suitable for everything. So, when a MT is required I use another gizmo:
BeadLock. It is a loose tenon gizmo that lets you make perfect fitting and
very strong MT joints with minimal skill and just an electric drill and
clamp. Like the PH it meets all the requirements, as in quick and easy. If
you've got both options you're pretty much covered.

Check it out: http://www.beadlock.com/

On 18 Feb 2005 14:27:51 -0800, "foggytown" wrote:


"Get rid of the Range Rover. You are not responsible for patrolling
Australia's Dingo Barrier Fence, nor do you work the Savannah,
capturing and tagging wildebeests."
--Michael J. Nelson

Don't laugh, but I actually live near a school where a guy teaches
off-road driving to dentists, Wall Street suits, etc... in Range
Rovers.

Rover provides vehicles to the school. The guy has been featured in
several magazines and makes an excellent buck doing it. I see it as
no different than the Richard Petty Experience for Outback wannabees.
G

The school is in East Haddam, CT.

Barry

foggytown wrote:
Pocket screw setups look much easier than mortise & tennon and,
apparently, are just as strong. Unless a through tennon extending
beyond the rail is required for structural or decorative reasons, are
the two systems actually interchangable?

FoggyTown

Chris Schwarz wrote a really nice review comparing the two types of
joinery in the most recent issue of Woodworking Magazine...