Author Topic: Clamping mitred boxes  (Read 3677 times)

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Offline Greendave

  • Posts: 29
Clamping mitred boxes
« on: January 02, 2017, 07:18 AM »
Happy new year all!
So i've been making a lot of plywood boxes with mitre joints and gluing them up one at a time with the use of 4 Bessey Band Clamps (the ones with vario corners). This has generally been working well but the process is slow and fiddly. Does anyone have any other methods of gluing up smallish (40 x 40 x 40cm) boxes that lend themselves to batch production so no using endless amounts of g-clamps and angled clamping blocks etc?

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Offline HarveyWildes

  • Posts: 363
Re: Clamping mitred boxes
« Reply #1 on: January 02, 2017, 09:52 AM »
Blue painters tape works for stuff that isn't too heavy.  Lay the pieces out flat on two pieces of tape, then wrap them together.

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #2 on: January 02, 2017, 10:27 AM »
Yeah that works great on small boxes but these are too heavy for that, it's 15mm plywood with dominos and a 9mm plywood back with an open front.

Offline mcooley

  • Posts: 153
Re: Clamping mitred boxes
« Reply #3 on: January 02, 2017, 12:04 PM »
I've had some luck with this design from Bessey. (Oops realized these are what you are using now)

I don't particularly like the "ratchet" design like what Rockler offers. It is too easy for the strap to bind.

http://www.besseytools.com/en/subcategory.php?ASIMOID_MC=000000000001f3f000030023&ASIMOID_SC=000000020003ebc900020023

Another design I would like to try for doing larger pieces are these. For small batch production these seem quick and easy to setup. My plan would be to use these at the corners and then once they are in place run your Bessey's in from the edges to get even pressure.   

https://www.fine-tools.com/frame-clamp.html

These are also nice given they don't weigh much and seem easy to adjust. They make it with a "miter attachment" which is on the second link below.

https://www.fine-tools.com/bar-clamp.html

https://www.toolsforworkingwood.com/store/dept/CDC/item/MS-ABAR.XX

https://www.thebestthings.com/newtools/uniclamps.htm
« Last Edit: January 02, 2017, 12:19 PM by mcooley »

Online Birdhunter

  • Posts: 1726
  • Woodworker, Sportsman, Retired
Re: Clamping mitred boxes
« Reply #4 on: January 02, 2017, 12:19 PM »
I use splines to achieve mitered joint alignment. My saw blade cuts a 1/8" kerf and I use 1/8" aircraft grade plywood as the spline. The spline keeps the sides from sliding out of alignment while being glued.

If I am worried about the splines showing, I use the same species as the sides for the splines.

Technique works well.
Birdhunter

Online Peter Parfitt

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Re: Clamping mitred boxes
« Reply #5 on: January 02, 2017, 01:25 PM »
@HarveyWildes has the right idea despite the reservations of @Greendave

Take a look at the way I did these long mitre glue-ups using ordinary masking tape. I had perfect results throughout this project using this method.



I know a chap who makes humidors that have solid silver hinges, lots of other bling and they retail at over $40k - he uses this same method for the boxes and some of them are not small at all.

Peter

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #6 on: January 02, 2017, 02:47 PM »
I've had some luck with this design from Bessey. (Oops realized these are what you are using now)

I don't particularly like the "ratchet" design like what Rockler offers. It is too easy for the strap to bind.

http://www.besseytools.com/en/subcategory.php?ASIMOID_MC=000000000001f3f000030023&ASIMOID_SC=000000020003ebc900020023

Another design I would like to try for doing larger pieces are these. For small batch production these seem quick and easy to setup. My plan would be to use these at the corners and then once they are in place run your Bessey's in from the edges to get even pressure.   

https://www.fine-tools.com/frame-clamp.html

These are also nice given they don't weigh much and seem easy to adjust. They make it with a "miter attachment" which is on the second link below.

https://www.fine-tools.com/bar-clamp.html

https://www.toolsforworkingwood.com/store/dept/CDC/item/MS-ABAR.XX

https://www.thebestthings.com/newtools/uniclamps.htm

Thanks for the links, i'm in the UK though so cost would be an issue with those. I can't actually see how they would work on a long mitre joint though or am I missing something?

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #7 on: January 02, 2017, 02:47 PM »
I use splines to achieve mitered joint alignment. My saw blade cuts a 1/8" kerf and I use 1/8" aircraft grade plywood as the spline. The spline keeps the sides from sliding out of alignment while being glued.

If I am worried about the splines showing, I use the same species as the sides for the splines.

Technique works well.

Thanks it's not an alignment issue though as i'm using dominos for that, it's the clamping that's the 'problem'

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #8 on: January 02, 2017, 03:01 PM »
@HarveyWildes has the right idea despite the reservations of @Greendave

Take a look at the way I did these long mitre glue-ups using ordinary masking tape. I had perfect results throughout this project using this method.



I know a chap who makes humidors that have solid silver hinges, lots of other bling and they retail at over $40k - he uses this same method for the boxes and some of them are not small at all.

Peter

Thanks Peter, that certainly does look like it works well but i'm not sure if it lends itself to batch production though. If i'm doing 25 boxes that's a lot more fiddling about with the tape than the method i'm currently using. I'm using a few of the smallest dominos for alignment so they may get in the way when carefully closing the mitre as you do in this video.
« Last Edit: January 02, 2017, 03:05 PM by Greendave »

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #9 on: January 02, 2017, 03:04 PM »
I'm looking for something more along the lines of this I think...pic attached

Offline Tim Raleigh

  • Posts: 3398
    • Oakville Cabinetry
Re: Clamping mitred boxes
« Reply #10 on: January 02, 2017, 03:08 PM »
Does anyone have any other methods of gluing up smallish (40 x 40 x 40cm) boxes that lend themselves to batch production so no using endless amounts of g-clamps and angled clamping blocks etc?

Use some clear packing tape along the outside of 3 miters, and one on the fourth edge, turn over apply glue, tape fourth side and let dry.
Doesn't require a lot of pressure.
Tim

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #11 on: January 02, 2017, 03:13 PM »
Does anyone have any other methods of gluing up smallish (40 x 40 x 40cm) boxes that lend themselves to batch production so no using endless amounts of g-clamps and angled clamping blocks etc?

Use some clear packing tape along the outside of 3 miters, and one on the fourth edge, turn over apply glue, tape fourth side and let dry.
Doesn't require a lot of pressure.
Tim

Thanks Tim, do you think I even need the dominos for alingment using this method, i'm not sure they add any strength anyway. Would just the glue be sufficient for a sturdy box that will be taking a lot of weight and more than one stacked on top of each other?

Offline Tim Raleigh

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    • Oakville Cabinetry
Re: Clamping mitred boxes
« Reply #12 on: January 02, 2017, 03:28 PM »
Would just the glue be sufficient for a sturdy box that will be taking a lot of weight and more than one stacked on top of each other?

It really depends on how much weight and quality of the wood and or orientation of the long grain. I would try it without first. If long grain to long grain, mdf or chipboard you usually don't need reinforcement unless you are applying a lot of weight. If end-grain, you definitely need reinforcement. I don't like dominoes for these joints as they can create more problems than they solve. I use biscuits, but cut them close to the inside to avoid telegraphing through on the front from the swelling biscuit.
Tim

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #13 on: January 02, 2017, 03:36 PM »
Would just the glue be sufficient for a sturdy box that will be taking a lot of weight and more than one stacked on top of each other?

It really depends on how much weight and quality of the wood and or orientation of the long grain. I would try it without first. If long grain to long grain, mdf or chipboard you usually don't need reinforcement unless you are applying a lot of weight. If end-grain, you definitely need reinforcement. I don't like dominoes for these joints as they can create more problems than they solve. I use biscuits, but cut them close to the inside to avoid telegraphing through on the front from the swelling biscuit.
Tim

I'm using 15mm birch plywood and they will be taking a lot of weight so thought dominos would help with that. OUt of interest what kind of issues did you have with them?

Offline Bohdan

  • Posts: 672
Re: Clamping mitred boxes
« Reply #14 on: January 02, 2017, 07:22 PM »
I used to make loudspeaker boxes and used the steel packaging bands with waxed aluminium extrusions for the corners for alignment. You crimp the bands on the boxes leaving an excess piece of banding so that when you cut them free the bands can be reused on the next box.

With sufficient corners you can glue all day long, the next day you cut the straps, wash and wax the corners and start again.

When the bands were used up on the big size you then used them on the next smaller box.

Offline Z48LT1

  • Posts: 36
  • My excuse is I never expected to be caught.
Re: Clamping mitred boxes
« Reply #15 on: January 02, 2017, 08:03 PM »
Would something like a pair of these work?

http://www.garrettwade.com/frame-clamp.html

They seem simple enough to cobble together in the shop.

Instead of the corner blocks, one could use a length of square stock with an edge removed like the pic in your post #8, also easy to construct.
« Last Edit: January 02, 2017, 08:22 PM by Z48LT1 »

Offline Tim Raleigh

  • Posts: 3398
    • Oakville Cabinetry
Re: Clamping mitred boxes
« Reply #16 on: January 02, 2017, 10:39 PM »
Out of interest what kind of issues did you have with them?

To close the miter with the glued dominos in place requires some pressure which pushes one or the other side of the miter out of alignment unless you use blocks and clamps at right angles to the miter.
[ Specified attachment is not available ]
You could try to use the domino in a hole with the widest setting to reduce the fricton.
Do a test with the miter fold technique described above.
Tim
« Last Edit: January 02, 2017, 11:08 PM by Tim Raleigh »

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #17 on: January 03, 2017, 05:45 AM »
Out of interest what kind of issues did you have with them?

To close the miter with the glued dominos in place requires some pressure which pushes one or the other side of the miter out of alignment unless you use blocks and clamps at right angles to the miter.
(Attachment Link)
You could try to use the domino in a hole with the widest setting to reduce the fricton.
Do a test with the miter fold technique described above.
Tim

Thanks, i'm definately giving that method a go but i'm concerned about strength when just using glue.

Offline Tim Raleigh

  • Posts: 3398
    • Oakville Cabinetry
Re: Clamping mitred boxes
« Reply #18 on: January 03, 2017, 11:43 PM »
Thanks, i'm definately giving that method a go but i'm concerned about strength when just using glue.

I just glued up some 1/2" 13mm mdo as a test for a plinth I am making and it is very strong. I stood on the corner and I can't break it.
Tim

Offline CNC Paul

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Re: Clamping mitred boxes
« Reply #19 on: January 04, 2017, 07:35 AM »
Dave,

I made these clamps for my boxes, I got fed up trying to hold the straps and corners on the Bessey clamps, these are all made from 18mm birch plywood.

I have changed the clamp nuts to plywood star handles with inserted T nuts.
http://www.fretworks.co.uk/

2D & 3D CNC Machining.  Laser cutting & engraving.

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #20 on: January 04, 2017, 09:46 AM »
Thanks, i'm definately giving that method a go but i'm concerned about strength when just using glue.

I just glued up some 1/2" 13mm mdo as a test for a plinth I am making and it is very strong. I stood on the corner and I can't break it.
Tim

Thanks Tim that's reassuring, i'm making one today with no dominos to test strength.

Offline Greendave

  • Posts: 29
Re: Clamping mitred boxes
« Reply #21 on: January 04, 2017, 09:49 AM »
Dave,

I made these clamps for my boxes, I got fed up trying to hold the straps and corners on the Bessey clamps, these are all made from 18mm birch plywood.

I have changed the clamp nuts to plywood star handles with inserted T nuts.

That's the kind of thing I need, less faffing around. Yep I agree the bessey clamps can get annoying especially when those vario corners pop off or get twisted.