Thread: Straight edge.

Try an aluminium spirit level for smaller sizes. Even the cheapies are usually very straight.
Otherwise I have used the edge of a sheet of mdf or chipboard as the giude to make a timber straightedge.

How accurate do you want? I've been using a 1900mm length of 100X30mm box-section aluminium since 1980. I've mounted 2 spirit level inserts into it and have used it for general purpose framing and fixing. It's been used and abused and it's still straight.

Of course, I wouldn't use it to measure flatness on my tablesaw.

Yep, agree with Bob and monoman.

Aluminium spirit level will be my #1 choice.
I will also suggest you to buy a 1m or 1.2m (not sure about the size) steel rule.

I have both.

Just a cautionary word about buying (and using) spirit levels. Please test the level in both planes (plumb & level) at the shop before buying it. This is real easy to do.

Plumb test:

hold the leve against some unmovable vertical object like a door jamb or wall, note where the bubble is. Now rotate the level 180 deg so that the other long face is against the vertical surface, note the reading. True plumb is midway between the 2 reading. If both readings are the same, then the bubble had better be in the middle of the marks, otherwise the level is cactus.

Level test:

Same as above, except test on horizontal surface, and swing level 180 deg around for second reading.

When you find one that passes both test, put it in its bag and take it home. I once tried every level in three stores in Albury before finding one that was even close.

One other thing. When using a level, always take 2 reading in the same way described above, and split the differnce.

Good luck.

I just use a 6' bit of 3mm flat aluminium bar. Box section would probably be better because it's rigid. On the other hand, it's sometimes handy if it bends.

For setting up a table saw, you don't need a 6' straight edge.

Buy a 1 metre or 1.2 metre steel or stainless steel rule. They are built dead straight (but watch the flex of the rule) and are pretty handy devices for marking out lots of things.

It will never go astray....go on...you know you really need one!!

Cheers,

P

Originally Posted by bitingmidge

go on...you know you really need one!!

Thanks guys, off to the shop with me to get one of them 1.2 m rules.

Dan

Hey Dan

Don’t pay $30 or $40 to buy the ones for Japan, USA and UK. I got mine from Mitre10. It was from Taiwan and was only $12.50. It is very good and the readings are engraved not printed.

Cheers

For large work, I use a strip of aliminum 3" wide and about 1/8 thick cut off the length of a 8 X 4 sheet of aliminum using an accurate guilitine. U may be able to get one for next to nothing from a sheet metal shop (look in the rubbish skip). Mine came from a coach building company I worked for many years ago (forgot to return it).

Chum

I was talking to a patten maker about straight edges & he uses a 1mtr stainless rule. His advice was buy: #1 American, #2 Japanese, #3 English & stay away from Chinese or Taiwanise as there is little accuracy in their scales. QUOTE: "Those bastards can be anything up to a full mil out in the first 100mm!!"

Fair enough Major,

I will compare them next time I go to the hardware store (tonight). Anyway Dan is looking for a straight edge.

I've got 1', 2', 4' and 5' Rabone graduated straight edges as well as 18" and 24" Stanley squares. I use all of them at different times and a bit of 4"X1" hardwood that is about 40 years old and 8' long that I dressed up years ago. Some are dual scaled, others are one or t'other. except the hardwood that is just straight

IMHO you can't have too many!!

Jamie

G'day.

I got the same one you did Wongo, I use it for ruling lines & cutting with
a stanley knife etc, I don't use it for measuring other than rough stuff
like finding the middle of something in a hurry.

This subject was covered here....
http://www.woodworkforums.ubeaut.com...ead.php?t=9685

I went to the local Ali distributor & bought a whole 6M length of 50x25x3 box for $90 & had it cut into 2.5M, 2 M & 1.5M for straight edges.

To stop any unwanted flexing, glue the widest side of the box to a strip of 4mm MDF using a known good straightedge as a guide to keep the Ali straight, EI: the edge of a sheet of 12mm ply. Leave enough overhang each side to suit you fav circ saw on one side & your fav edge trimming router bit on the other side.

Then, once it's set dry & hard, to finish the guide, lop off the extra overhang each side, set you saw square & run it down the 'saw' side & do the same with your router on the ‘trim’ side.

When you want to rip/hack/trim a long edge straight/smooth, clamp the straightedge onto it with the appropriate edge along the line you want to rip/hack/smooth/straighten & plough in.
The guide edge of the power tool base follows the ali straight edge & the tool blade/bit runs along the already trimmed edge of the MDF & there you have it.

This is not a new idea but it is worth following.

& Midge, to answer your questions from last time....

I used Wellbond & I don't intend to take the old bit off,
just trim it back level with the Ali box & glue it to the new piece.

If it did get ripped up or wet, you could flip it over & use the other side of the Ali box.

A belt sander over the Ali box should also clean it up 'cos that surface is not
critical to the straight edge.