Getting a large-ish piece of ply square

[Wizard9999]

All

Stupid novice question, but at the risk of looking foolish I am going ahead and asking.

I have apiece of ply which is almost square, but not quite. I need it square. I can cut two face parallel on my tablesaw, but it is too big to cut using the mitre gauge to square it up. I don't have a sliding table on the table saw, I am at a loss as to how to square it up other than by using my plunge saw and track. Am I missing something or is that the best / only way?

Terry.

 

[Rod]

If it's too big for your table then 3:4:5 Triangles and your plunge saw.

Rod

 

[Mike G]

Or invest a few pennies in a roofer's square. Once you have one, you'll be surprised how often to use it.

 

[9fingers]

+1 for roofers square and totally agree about the rate of usage. Much more than I expected after completing the workshop roof.

 

[RogerS]

Or make a Square of Thales

http://www.ukworkshop.co.uk/videos/chec ... quare.html

 

[Woodbloke]

If it's too big for your table then 3:4:5 Triangles and your plunge saw.

Rod

:text-+1: and get hold of a roofer's square, very useful bit of kit - Rob

 

[9fingers]

Terry, So far people have been telling you how to measure the right angle rather how to cut it.

The first part of this video tells you how to make a panel cutter for your table saw.

Make sure the saw blade is set perfectly parallel to the table slots - you have possible done this already.
Use some or all of the techniques people ave given you to measure a right angle in the manufacture of the jig.

I can't remember if you saw mine when you visited but it is very useful indeed.

The video is from the Marmite of US woodworkers :lol: - I happen to like him but love him or hate him, this jig works!

https://www.youtube.com/watch?v=7Lc6ItDd7Q0

Bob

 

[Woodbloke]

... rather how to cut it.

Bob

Two of us have both mentioned plunge saws, such as the Festool TS55

If it's too big for your table then 3:4:5 Triangles and your plunge saw.

Rod

and me

If it's too big for your table then 3:4:5 Triangles and your plunge saw.

Rod

:text-+1: and get hold of a roofer's square, very useful bit of kit - Rob

...but I agree, if Terry doesn't have one, then other methods need to be used - Rob

 

[9fingers]

A track saw will only facilitate cutting straight lines
A panel cutting jig will enable right angles to be cut which I thought was the kernel of the question.

Bob

 

[Wizard9999]

Thanks guys, I do have a plunge saw, but I don't think I have what you are referring to as a roofer's square but I do have a very large folding square. Rather ironically the piece I want to square off is in fact destined to become a part of a sled for my table saw :lol: . Have been distracted for the moment and am building a cabinet for my drill to stand on, but more importantly it will give me more drawers and therefore storage which seems to be in critically short supply at the moment.

Experience so far has already made it clear that getting things square is gong to be a recurring theme for me. The cabinet I am making will no doubt be OK for the workshop, but it is by no means good enough for anything you could call furniture.

Thanks again for the tips.

Terry.

 

[Woodbloke]

A track saw will only facilitate cutting straight lines
A panel cutting jig will enable right angles to be cut which I thought was the kernel of the question.

Bob

That's true, but if you set the track up correctly, it will cut a true right angle. For cutting sheet material (and other stuff besides) these things are a revelation, so much so that for this particular application, I can't personally see the need for a huge (or even small) tablesaur - Rob

 

[RogerS]

Of course, Marmite's jig is only as good as the accuracy of how parallel the slot in the table saw top is to the blade.

The thing is that with cutting a large square piece, you only have to be a fraction of a mm out at the start for it to magnify into a much larger error by the time you've reached the end of your cut.

Rob, how do you set up a track saw to cut 90 degrees if you don't have a large accurate square?

 

[Woodbloke]

Rob, how do you set up a track saw to cut 90 degrees if you don't have a large accurate square?

I have such a beast and if I didn't, I know where to get one from - Rob

 

[9fingers]

Of course, Marmite's jig is only as good as the accuracy of how parallel the slot in the table saw top is to the blade.

Having thought about this a bit more, the parallelism of the blade and slot is irrelevant to the accuracy of this jig*. The accuracy is totally and solely dependant on the angle between the underside guide strip and the stop strip on the upper side.

The cut quality may vary with offset however.

Bob

 

[Rod]

I was thinking of much larger sizes than the ones shown on the video.
The other way is to make up a large shooting board and plane to an accurate line.

Rod

 

[RogerS]

Of course, Marmite's jig is only as good as the accuracy of how parallel the slot in the table saw top is to the blade.

Having thought about this a bit more, the parallelism of the blade and slot is irrelevant to the accuracy of this jig*. The accuracy is totally and solely dependant on the angle between the underside guide strip and the stop strip on the upper side.

The cut quality may vary with offset however.

Bob

You're right. While I was typing this, the little man who sits on my shoulder and usually nags me if I forget something was muttering 'Are you sure?' to me and, as usual, I ignored him!

He nags me but never tells me what it is I have forgotten. I ignore him at my peril.

 

[Rod]

I quite like Norm (apart from his safety techniques) and have made a few of his designs/projects.

I have been thinking what I've used in the past and although I have other sleds, I've never made one like Bobs. Probably because I use an Incra 1000SE mitre gauge on my TS which gives support of about 800mm (with one end just clear of the blade) - it extends from 18" to 31" .
My TS has a LHS side width of 20"

Rod

 

[Wizard9999]

I quite like Norm (apart from his safety techniques) and have made a few of his designs/projects.

I have been thinking what I've used in the past and although I have other sleds, I've never made one like Bobs. Probably because I use an Incra 1000SE mitre gauge on my TS which gives support of about 800mm (with one end just clear of the blade) - it extends from 18" to 31" .
My TS has a LHS side width of 20"

Rod

It was not the width to the left of the blade that was / is the problem, it is the space between the front of the blade and the mitre gauge on a roughly square piece.

However, I think the answer was hiding in the corner of the workshop all along. A while back I bought an MFT 'style' top from a chap on another popular wood working forum, I also have the necessary parf / bench dogs, so creating a right angle cut with my track saw should be a piece of cake. The top is not yet attached to anything, but I can clamp it to my outfeed table and as it is 1200mm long there is a lot more space to make the cut than the distance from the back of the table saw blade and the front of the mitre gauge.

Terry.

 

[Rod]

Oops you are correct Terry - me not thinking straight!

Rod

 

[TrimTheKing]

Hi Terry

I'm a bit lost with this thread and what you're actually trying to achieve, but I think you are making a sled and this is the tope. If that's the case, why do you care about how square it is?

If it's the top then it could be a triangle for all the difference it makes, the real issue is getting the slots in the table parallel to the blade and getting your back fence perpendicular to the slot, all the rest is irrelevant.

Excuse me if I've misread what you're trying to achieve!

Cheers
Mark

 

[Wizard9999]

Mark

Yes, you are right, but once the question popped up in my mind I wanted to put it out there.

Terry.

 

[AndyP]

Getting the back fence perpendicular is easy. Make it adjustable.

 

[Rob]

I've got a roofing square you can borrow by the way Terry.