Cutting 45 degree angles

[kornnylike]

Hi

I am having some trouble cutting 45 degree angles and other angles. Also i want to know of a table saw is better at cutting angles than a circular saw.

Here is an eg. of the problem, if i have a peice of plywood that measures say 9" and both ends need to be cut at 45 degree angle. After cutting both ends of the plywood at 45 Degree and try to fit it the plywood measurement would came short.

Tips please

[kevinahcc20]

For miter cuts in material of moderate width a good sliding chop saw is the best tool, but its capacity is limited to the travel of the slides and the degree of the angle. Most 10" sliders will cut 12" widths at 90° and a bit over 8" (12*0.707) at 45°. At larger widths the tablesaw provides more capacity depending on the size of the table and miter bar...best results come with a sled set up to cut angles. There are two issues you need to address to get a successful miter joint. The 1st is setting the angle accurately which should be done with a 45° miter square. Then you have to mark and make the cuts at the proper location on the workpiece. A small angular error in a wide workpiece can leave a large gap when the pieces are mated together.

[tvrgeek]

The same tip as how to get to Carnegie Hall. "Practice man, practice"

Of course, the table saw with a big sled is better, but it takes up a lot of space and is not cheap. The little portable ones are for, well little portable use. ( They scare the heck out of me to use) Even with my big "Rigid" which is actually built by Emerson and the same as the bigger Sears, getting perfect miters is not easy.

Quality of the blade matters. Support for the saw and sufficient fence helps. I have seen work done with a $20 circular saw that could put a cabinet maker to shame. Getting the perfect 45 is a matter of cutting a a angle, flopping the board and placing then along a straight edge. You will see twice the error in the joint. Adjust , repeat, adjust, repeat.

If you happen to be in Maryland, I could make you a heck of a deal on a radial arm saw.

[ODougbo]

Yo Kornnylike,

There are several ways:

> 9” miters can be cut on one of the new sliding miter boxes.

> Use good quality 45degree router bit, use straight edge.

> Put a good size piece of scrap wood on a table saw fence. Bring the bade up until you are touching the wood (at the 45 degrees). Run the wood edge (only) through the saw – this will take micro adjustments to get it right, but works beautifully.

Issues cutting miters in a small shop:

Is the material perfectly flat? If not the material will “lift” and run off course.

Is the blade super sharp? If not the material will “lift” and run off course.

Is the table saw set up perfectly? Not at easy as it sounds.

An outboard table for a table saw is a must, level up everything.

[kornnylike]

Thanks for the tip do have any pic to show what you are talking about.

[ODougbo]

It threw me too when I first heard of this. The panel will have to be cut “perfect size” – before the miter.

In short: the table saw is converted into a 45degree cutter; almost like a shaper.

You can miter cut 8”, 12", 36"…whatever, the fence never moves; also the blade would cut into the fence if it wasn’t for the scrap wood.

I didn’t believe it would work until I tried it.

I'll send you a photo.

[kornnylike]

Originally Posted by ODougbo

It threw me too when I first heard of this. The panel will have to be cut “perfect size” – before the miter.

In short: the table saw is converted into a 45degree cutter; almost like a shaper.

You can miter cut 8”, 12", 36"…whatever, the fence never moves; also the blade would cut into the fence if it wasn’t for the scrap wood.

I didn’t believe it would work until I tried it.

I'll send you a photo.

Thanks for the help

[ltorcida]

I will go with a table saw....but even with this tool available, the calibration must be perfect to the 0.0001"
Is one of the most demanding cuts to do perfect. The longer the cut, the more prone to errors.
Practice, Practice and more practice, even with the right tool.

[pski]

Originally Posted by ltorcida

I will go with a table saw....but even with this tool available, the calibration must be perfect to the 0.0001"
Is one of the most demanding cuts to do perfect. The longer the cut, the more prone to errors.
Practice, Practice and more practice, even with the right tool.

No. A 1/32" will work. Nobody can do a ten thousandth of inch on a table saw. The angle accuracy is as important as the x-y.

P

[ODougbo]

The table saw calibration should be good as you can get it (not as easy as it sounds).
As mentioned in #4, the material is an issue; impossible to cut a good 45 on a warped/twisted board.

#3 is not a bad way to go if the material is not flat/straight, make up a long sled for the "skill saw" to ride on.