Squaring edges from a circular saw cut (1 Viewer)

[Garret_O]

Hey all,

Well, my table saw connection fell through so now I've resorted to cutting my MDF with a circular saw and a straightedge. It is working ok thus far but the one thing that is annoying is at the end of the cut it seems the edges aren't 90 up/down (the 3/4" width). Anyone have hints on the best way to square these up?? I've read that some use a router or possibly an orbital sander. I have both so any hints would be great.

I'm seriously considering picking up a BT 3100 from Home Depot (since I lost my cutting hookup). The circular saw/straightedge thing takes me forever to line up and cut, and I'm getting these "slightly" off edges at the end. I figure the BT would be decent as it is fairly small and seems to be portable (only have 1 car garage).

ANy thoughts and/or suggestions would be helpful.
THanks in advance,

Garret

 

[Darren_T]

It's gonna be tough without machinery. You can try with a sander.

The best thing to do is square up the circular saw blade to the sole. Tackle the problem at the source.

Darren

 

[Dan Wesnor]

Square up the saw blade. Get a nice machinist's square. Never trust the angle gauge that's on the saw.

 

[Garret_O]

Hey Darren, Yeah, I tried to square it up at the sole. I checked it with my t-square. Is there a better method to that madness?

I'm thinking I could just clamp the two pieces that should be the same together and sand them so at least they will be equivalent, but i'm still really close to just buying the table saw.

Later,

Garret

 

[Darren_T]

The table saw will be the ultimate solution but you'll need to square it up also after you purchase it. It could be right on but you still should check. As Dan said, use a good machinist's square. They are only like $15 and dead accurate. Use this square only to check other squares and to tune equipment. Never drop it and always keep it in a safe place. It will be your reference. A "T" square is not a good tool to try and square a blade, they are usually waaaaaaay off. Good for framing but not even close to accurate enough for machine tuning. Same goes for a contractor square. I've never bought one that was even close to square.

Darren

 

[Dan Wesnor]

You should check your table saw blade for square every time you use it. It doesn't matter how much money you pay for the saw, the blade will move over time.

And like Darren said, a framing square is not a good square.

This is a good square:

http://www.amazon.com/exec/obidos/tg...&s=hi&n=228013

 

[Garret_O]

I'll have to grab a machinist's square. I just knew the squares I was using weren't square. Darnit. I just wasted a chunk of MDF. I was lining up the rip guide with a t-square and a carpenter's square. They were off.

I have to find a combination/machinist's square asap! I'm sure HD has them right? (looks like they don't have "good" ones)

Later
Garret

EDIT: Sorry- I just saw your note Dan, Thanks.

 

[ChristopherD]

Would it be possible to set up a straightedge and go down the side w/ a spiral bit in the router?

 

[Garret_O]

Yes, I'd imagine I could do that. Just another thing to set up and try to get straight right? It is just tricky when you are looking at 1/16th of an inch difference.

 

[Dennis XYZ]

Use a flush trimming bit in the router with a factory MDF edge as a guide (check to make sure it's straight.) Cut the piece a hair big (you may not even need a straight edge) and flush trim it to the lines.

Best for this:
http://www.mlcswoodworking.com/shops.../bt_patrn.html

Also useful:
http://www.mlcswoodworking.com/shops.../bt_flush.html

 

[Garret_O]

Ok Dennis, so I just clamp a factory edge on top of the cutt edge and use the flush bit? Looks good to me.

Thanks for the tip. I'm guessing a 1/2" collet with a 1" depth would be good.

I wonder if I can find something similar locally.

Woodcraft

Looks like that would trim veneer nicely as well (bottom bearing).

 

[Dennis XYZ]

so I just clamp a factory edge on top of the cutt edge and use the flush bit?

Yep, you've got it!

That pattern bit is also great for mounting weird shaped drivers if you have a lot of them to do. Take your time making a good pattern and then use it for all the cuts.

 

[Jacques C]

For a long term solution the BT3100 is a good way to go. The rip fence (once aligned, which is straighforward) is repeatably straight.

I have the BT3000 and am very happy with it. I think the promotion for the free accessory kit is still going as well. There is some very nice stuff in there.

Take care.

Sand

 

[John Walker]

The straight edge and router is the only way to go if you don't have a quality table saw (and panel cutting jig).

I have Home Depot "rough cut" all my sheet goods to 1/4" oversize and then trim and square at home. Works fantastic - better than a table saw if you're careful.

*Use a 1/2" shank - 3/4" cutter WITH A TOP BEARING. The top bearing is the only way to go because you clamp your straight edge ON TOP of the work piece (where you can see your pencil marks) and zip off the edge. There is no calculating the offset from the router base etc when using a bearing bit. As far as I know top bearings are only available in larger cutter sizes because the bearing has to be big enough to fit over the shaft (unlike a bottom bearing which fits on a tiny set screw).

Use a piece of MDF with a factory edge for your straight edge. It should be about 8" with to fully support the router and accommadate clamps. It should also be longer than the work piece so you don't ruin the end.

Once you use this technique (cut over size and router/straight edge trim) you'll never go back.

John