MFT/3 trick. Probably been done before

[iamnothim]

Take the screw knobs you never use from the "Clamping Elements" and secure a ratchet strap to the top of the MFT with the cleat part under the table.
Now you can secure large items to the top.

 

[Zacharytanner]

Great Idea

Frank

 

[Administrator_JSVN]

First time I've seen it. Nice one.  [thumbs up]

 

[gsdvorak]

Thanks for sharing- I will definitely be using this trick!

Regards,
Gerald

 

[Sparktrician]

Great idea!!! 

 

[sancho57]

I never thought of that. Ill have to keep it in mind when I need something like that

 

[iamnothim]

Thanks for the positive feedback guys.   [smile]

Do you think it would work to put a caul on top of the cabinet, that is slightly larger, and pull it down for glue-up?

BTW:  It worked great securing my upper cabinets while adjusting the doors.

 

[Sparktrician]

Don't forget to take into consideration the relative weakness of the MDF of the MFT top.  By that I mean, don't put do much stress on it by cranking down hard on the strap over a caul and have the MDF blow out. 

 

[iamnothim]

Don't forget to take into consideration the relative weakness of the MDF of the MFT top.  By that I mean, don't put do much stress on it by cranking down hard on the strap over a caul and have the MDF blow out. 

yup.
duly noted.

 

[bkharman]

I did something similar in the past.  I actually had the straps going around the workpiece and the exterior frame of the MFT.  I also put some tiger wood boards between the MFT and box to made the MDF a bit more rigid. 

Nice job "using what you have"

cheers.  Bryan.

 

[iamnothim]

I set this up because I wanted to see if I could fix a cabinet the was greatly out of square.
I just now tried it and I can't believe it worked.  It wouldn't budge by hand.

Now I can affix a square piece behind the back and it "should" hold it square.

I'm amazed.
Any recommendation from cabinet makers on  how to hold it square will be appreciated.

 

[rst]

If? you have a a long enough clamp, you can place the clamp diagonally across the corner and GENTLY pull the cabinet into shape.  The cheap pipe clamps work well for this as you can just buy 3/4" black iron pipe for any length.  I actually have made 10'ers to clamp up store displays like this.

 

[wow]

If? you have a a long enough clamp, you can place the clamp diagonally across the corner and GENTLY pull the cabinet into shape.  The cheap pipe clamps work well for this as you can just buy 3/4" black iron pipe for any length.  I actually have made 10'ers to clamp up store displays like this.

I have some 8' K-body clamps that I have used for this. For those who haven't done this before:

1. Measure corner to corner diagonally (imagine measuring one of the lines in an 'X'). Write down your measurement
2. Now measure the other diagonal. Write it down.
3. Add the two dimensions together, then divide by 2. This is your ' true square' length that both lines of the 'X' should be equal to.
4. Place clamp across longest dimension and CAREFULLY tighten it until it is the correct length. Your cabinet is now square, but may not stay that way once the clamp is released, so

5. Attach a back piece, brace, or whatever to hold the cabinet square. To compensate for spring-back I will often tighten the clamp a small amount beyond square, then brace the piece and slowly release the clamp.

6. If necessary, repeat steps 4 and 5 until square.

 

[tiralie]

I set this up because I wanted to see if I could fix a cabinet the was greatly out of square.

Just take the back off next time and you will be able to move it by hand.

Now I can affix a square piece behind the back and it "should" hold it square.

Maybe, but I wouldn't bet on it. Doing this you have loosened the joints. Over time it is likely to move back to the old position. You need to remove the back and put a new one on there to hold it in position. Measure the legs and horizontal and make sure they are all the same size.

Any recommendation from cabinet makers on  how to hold it square will be appreciated.

Remove the old back, rabbet the back of the shelf top and legs and cut and attach a new back that fits tightly into the new rabbet.

Tim

 

[iamnothim]

WoW and Tim,

Thanks for the tips.
When I first stated looking at it I figured a new back might be the only solution.  It just made sense.

I tried the straps. It turned out the ratchet straps didn't do much. (Other than lift the table up.)  A corner was square in one direction.... of the long edge on the square, not the other.

After poking around I determined that most of the problem is warped sheet goods.  If I pushed the bottom out and I got it close to square.  I also added the top and bottom stretchers using pocket screws on three sides.  Then I hung the doors and discovered that some of the stiles and rails are warped.  I can’t fathom how this happened.  The cabinets are made of 3/4 pre-finished birch ply.  The styles and rails are made out of 3/4 “Medex” brand MDF.  I paid a premium for this.  I checked some of the base boards I also ran out of Medex and picked up a bowed one straight away.

I’ve had the material a couple weeks.  I live in Southern California with near perfect weather.  I happen to have a Temp/RH data logger in the garage that was left over from another project.  I put it in because I have veneers.  Anyway the between March and May, 21,000 samples, the logger calculated an average RH of 46% and an average temp of 62 deg.

I’m at a loss.  The only thing I can figure is the materials were defective when they were delivered.

 

[tiralie]

After poking around I determined that most of the problem is warped sheet goods.

So your sheet goods were warped when you built the case or did the Medex warp?

I’m at a loss.  The only thing I can figure is the materials were defective when they were delivered.

Probably. Always check for and then return crap.

The styles and rails are made out of 3/4 “Medex” brand MDF.  I paid a premium for this.  I checked some of the base boards I also ran out of Medex and picked up a bowed one straight away.

Medex or MDF is not a good solution for rails and stiles and certainly not ones as long as yours. Use solid wood poplar or maple or what ever.

I’m at a loss.  The only thing I can figure is the materials were defective when they were delivered.

[/quote]

 

[iamnothim]

After poking around I determined that most of the problem is warped sheet goods.

So your sheet goods were warped when you built the case or did the Medex warp?

I’m at a loss.  The only thing I can figure is the materials were defective when they were delivered.

Probably. Always check for and then return crap.

The styles and rails are made out of 3/4 “Medex” brand MDF.  I paid a premium for this.  I checked some of the base boards I also ran out of Medex and picked up a bowed one straight away.

Medex or MDF is not a good solution for rails and stiles and certainly not ones as long as yours. Use solid wood poplar or maple or what ever.

I’m at a loss.  The only thing I can figure is the materials were defective when they were delivered.

[/quote]

I guess I was mistaken that MDF is more inert than solid lumber. I'll give that a try next time.
Thanks for replying.

 

[tiralie]

I guess I was mistaken that MDF is more inert than solid lumber. I'll give that a try next time.

MDF will bend if you look at it wrong. If you sprayed one side and had it in a drying rack it will sag. If you lean a piece against the wall, and your dog comes along and pees on it it will bend.

You have to carefully consider construction techniques when using MDF. A door needs to be structurally sound. MDF isn't the best for structural work, but if designed properly can be used as a structure.
For instance mdf constructed as a box or even an I beam can be used structurally.
Tim

 

[iamnothim]

I guess I was mistaken that MDF is more inert than solid lumber. I'll give that a try next time.

MDF will bend if you look at it wrong. If you sprayed one side and had it in a drying rack it will sag. If you lean a piece against the wall, and your dog comes along and pees on it it will bend.

You have to carefully consider construction techniques when using MDF. A door needs to be structurally sound. MDF isn't the best for structural work, but if designed properly can be used as a structure.
For instance mdf constructed as a box or even an I beam can be used structurally.
Tim

Actually Sierrapine Medex MDF is different.  I wanted to use it for my baseboards but was concerned about water effecting it, so I tested it by submerging a foot long piece underwater overnight.  Nothing happened.  When it came out it was as hard as a fresh piece.  I think I didn't pay attention to the sheet(s) that were delivered.  I have some similar issues with 3/4" birch ply that I got from the same outfit.