[DaleFiorillo]

I have a piece of 1/4" hardboard cut to 6x12". My challenge is to get a perfectly centered 4x4" square cut out, with smooth edges and sharp corners. It will be a template. I don't want it to take forever. The layout is no problem, just getting straight and smooth sides. The ol'saber saw is not smooth enough. Any ideas? I thought about routing, but I'd need a template to make a template :laugh2:

 

[Stick486]

plunge cut a template w/ a table saw ....
cut the final w/ a router from the template or just use the plunge cut piece...

 

[MT Stringer]

Any ideas? I thought about routing, but I'd need a template to make a template :laugh2:

I have done that exact thing. Used double sided tape to stick pieces of mdf around the layout. Then use the jig saw to cut away most of the waste. Next, use a 1/4 inch pattern bit to rout the inside of the temporary template by following the mdf with the bearing on the pattern bit. Then you will have to hand trim the corners.

Think about it, maybe do a test or two on scrap, then go for it.
Good luck.

FYI - here are some videos to check out.
https://www.youtube.com/results?search_query=make+a+template+for+router

 

[john60]

plunge cut with multipurpose tool with square blade or find someone good with scroll saw

 

[Danman1957]

Dale,

Is there a local laser cutting company close by, this would be so easy for them, I can't imagine they would charge too much and it would be very precise.
Dan

 

[CharleyL]

I frequently cut needed templates with my scroll saw. Perfectly straight cuts are a little difficult on a scroll saw, but the error is usually so little that a sanding stick will straighten it with just a few strokes. The scroll saw cuts so clean that I rarely need to do anything else before putting it into use.

Charley

 

[harrysin]

In my years of experience of template making this is the only way to make a perfect "cutout" Modern adhesives will certainly hold the four pieces together even with hardboard.

 

[Garyk]

A cross cut sled on a table saw would work IF you have one straight side to begin with. If no side is straight you can make a sled that goes against the fence from a piece of plywood (factory edge) with a few hold downs that gives you a straight cut to have a good side to start with. Posted in 2013: http://www.woodworkingtalk.com/f27/s...rip-jig-40532/

Down the road such jigs come in handy so the moral of this story is you never have too many jigs.

 

[DesertRatTom]

I'd probably start with laying out the cutout, finding center then use a large Forstner bit to hog out the center. Then some smaller bits in the four corners, then chisels for the rest. I'd probably leave it a little proud then some sandpaper on a block to perfect the sides and corners. But the best way to do this would depend a lot on your tools. If I used a chisel in the corners, i'd sharpen the heck out of it first, and I'd scribe the line so it didn't splinter.

I also might choose to use four guide boards as Harry suggests to rough cut the center opening. Cut the outside dimension with the table saw, then lay four boards close around it to define the opening and use a bottom bearing trim bit to cut the inner opening, and use sandpaper to perfect the opening. This would only work if you have your bit perfectly centered. I'd use a trim router because it's smaller and more manageable. You'd have to place the guide boards so the inside cut was accurate, or a little proud so you can sand it flat.

This is definitely going to depend on what tools you have. Or, take it to a local CNC shop and get it done quick and easy.

Lots of ways to skin this cat.

 

[DesertRatTom]

I'd probably start with laying out the cutout, finding center then use a large Forstner bit to hog out the center. Then some smaller bits in the four corners, then chisels for the rest. I'd probably leave it a little proud then some sandpaper on a block to perfect the sides and corners. But the best way to do this would depend a lot on your tools. If I used a chisel in the corners, i'd sharpen the heck out of my chisel first, and I'd scribe the line so it didn't splinter.

I also might choose to use four guide boards as Harry suggests to rough cut the center opening. Cut the outside dimension with the table saw, then lay four boards close around it to define the opening and use a bottom bearing trim bit to cut the inner opening, and use sandpaper to perfect the opening. This would only work if you have your bit perfectly centered. I'd use a trim router because it's smaller and more manageable. You'd have to place the guide boards so the inside cut was accurate, or a little proud so you can sand it flat.

This is definitely going to depend on what tools you have. Or, take it to a local CNC shop and get it done quick and easy.

Lots of ways to skin this cat.

 

[harrysin]

I'd probably start with laying out the cutout, finding center then use a large Forstner bit to hog out the center. Then some smaller bits in the four corners, then chisels for the rest. I'd probably leave it a little proud then some sandpaper on a block to perfect the sides and corners. But the best way to do this would depend a lot on your tools. If I used a chisel in the corners, i'd sharpen the heck out of it first, and I'd scribe the line so it didn't splinter.

I also might choose to use four guide boards as Harry suggests to rough cut the center opening. Cut the outside dimension with the table saw, then lay four boards close around it to define the opening and use a bottom bearing trim bit to cut the inner opening, and use sandpaper to perfect the opening. This would only work if you have your bit perfectly centered. I'd use a trim router because it's smaller and more manageable. You'd have to place the guide boards so the inside cut was accurate, or a little proud so you can sand it flat.

This is definitely going to depend on what tools you have. Or, take it to a local CNC shop and get it done quick and easy.

Lots of ways to skin this cat.

Tom, the four pieces ARE the template. As shown in one of the shots, the simple formula to calculate the size of opening in the template is: dia. of template guide minus diameter of the bit plus the size of the finished project.

 

[bfblack]

I agree with harrysin's suggestion. I used this technique on jigs that require square corners as in the attached photo of a band saw jig for cutting an inside radius.

 

[beserkleyboy]

I vote for Harry's idea. I use that very idea for lots of things. If concerned about joining the 4 pieces, just fasten another overlapping layer on top. Masonite or MDF is perfect. I use 23ga headless pinner to fab jigs and such. With this method, you could have a template in 10 minutes flat...cheers, guys
Jim Pearson
30 yr expat in AUS

 

[tomp913]

Needing to cut some slots of the legs for my adjustable workbench, I made this jig from 1/2" MDF - as said, takes about 10 minutes (plus drying time). I made extra length of the center block once I had the perfect fit on the guide bushing so I can make more in the future.