Routing Question

[jronman]

Lets say I need to cut a specific path in a board. I make a template with my cnc and attach to the workpiece. The workpiece is 1-1/2 inches thick. What would be safer? Do I just take my 1/2 inch spiral flush trim bit and just do a full send on the piece or should I jigsaw close to the template path and cleanup with the flush bit? I tried the jigsaw method previously and my board was hard to control when I wanted to flush trim. I was getting unintended climb cuts which are scary. Thankfully no injuries. My theory on the full send was maybe since there is material on both sides of the bit the desire for the bit to climb cut on each side would cancel itself out. Thats just a theory. I could be very wrong in my thinking. I don't exactly need a bit that long every day and therefore I don't have much experience with longer bits apart from school when I had access to a shaper and pneumatic work holding sled.

I know a work holding sled would help but I didn't have one at the time and it would have to be custom because of the irregular shapes. I Know the template/workholding sled will need a way to swap out templates and have them secured plus have the ability to secure the workpiece to the sled. I was thinking the sled could have countersunk through holes for screws that would go into threaded inserts on the templates. on top of the sled would be a few pieces of t track to have some toggle clamps to hold the workpiece.

 

[peter halle]

Personally I would trim close with the jig saw and then do multiple shallower trims even if that means that a new router bit is in order with a reduced cutting length.  Taking on 1 1/2" of wood at one time is risky.  or at least I would consider it risky.

Peter

 

[woodferret]

Jigsaw and use a hand held router on a wide base with handle.  Learn to vary and back off the engagement as need be.  You don't have to bury it to the bearing.  Take light passes.  The base acts as a pseudo pin.  Table pins tend to only get used on start and rarely does anyone return to it for more control.

 

[jeffinsgf]

Lets say I need to cut a specific path in a board. I make a template with my cnc and attach to the workpiece. The workpiece is 1-1/2 inches thick. What would be safer? Do I just take my 1/2 inch spiral flush trim bit and just do a full send on the piece or should I jigsaw close to the template path and cleanup with the flush bit? I tried the jigsaw method previously and my board was hard to control when I wanted to flush trim. I was getting unintended climb cuts which are scary. Thankfully no injuries. My theory on the full send was maybe since there is material on both sides of the bit the desire for the bit to climb cut on each side would cancel itself out. Thats just a theory. I could be very wrong in my thinking. I don't exactly need a bit that long every day and therefore I don't have much experience with longer bits apart from school when I had access to a shaper and pneumatic work holding sled.

I know a work holding sled would help but I didn't have one at the time and it would have to be custom because of the irregular shapes. I Know the template/workholding sled will need a way to swap out templates and have them secured plus have the ability to secure the workpiece to the sled. I was thinking the sled could have countersunk through holes for screws that would go into threaded inserts on the templates. on top of the sled would be a few pieces of t track to have some toggle clamps to hold the workpiece.

A 1/2" cut 1-1/2" deep is asking a lot. I would cut just off the template. What I would suggest is getting a flush trim/pattern bit...that is one with a bearing on both ends of the cutter. With just a little bit of practice you can read the grain and anticipate the grabs. With bearings on both ends you can flip your piece over, adjust the bit height and always work downhill and/or with the grain.

The following suggestion makes my first suggestion unworkable, but I've done both. You were describing a sled that would accept interchangeable templates. It also sounds like you don't want to engineer that right now. I don't blame you. Another option is to create a one-off template sled. A big, heavy sled that keeps you away from the bit is a big confidence builder.

 

[bobtskutter]

I did something similar on a recent table project I made for my son.  I had a piece of plywood 54mm thick to trim to a template.
I drew around the template, then trimmed with the jig saw.
Then used a guide bush to position the cutter and trim a little off the work piece.
I changed the guide bush to a smaller one and then trimmed again.
Eventually I ran the bearing guide around the template to trim to the final size.
https://www.festoolownersgroup.com/member-projects/a-train-set-table-for-my-son/?action=dlattach;attach=359286;image

A lot of work, but it for me (I'm not a pro).

Regards
Bob

 

[jronman]

Lets say I need to cut a specific path in a board. I make a template with my cnc and attach to the workpiece. The workpiece is 1-1/2 inches thick. What would be safer? Do I just take my 1/2 inch spiral flush trim bit and just do a full send on the piece or should I jigsaw close to the template path and cleanup with the flush bit? I tried the jigsaw method previously and my board was hard to control when I wanted to flush trim. I was getting unintended climb cuts which are scary. Thankfully no injuries. My theory on the full send was maybe since there is material on both sides of the bit the desire for the bit to climb cut on each side would cancel itself out. Thats just a theory. I could be very wrong in my thinking. I don't exactly need a bit that long every day and therefore I don't have much experience with longer bits apart from school when I had access to a shaper and pneumatic work holding sled.

I know a work holding sled would help but I didn't have one at the time and it would have to be custom because of the irregular shapes. I Know the template/workholding sled will need a way to swap out templates and have them secured plus have the ability to secure the workpiece to the sled. I was thinking the sled could have countersunk through holes for screws that would go into threaded inserts on the templates. on top of the sled would be a few pieces of t track to have some toggle clamps to hold the workpiece.

A 1/2" cut 1-1/2" deep is asking a lot. I would cut just off the template. What I would suggest is getting a flush trim/pattern bit...that is one with a bearing on both ends of the cutter. With just a little bit of practice you can read the grain and anticipate the grabs. With bearings on both ends you can flip your piece over, adjust the bit height and always work downhill and/or with the grain.

The following suggestion makes my first suggestion unworkable, but I've done both. You were describing a sled that would accept interchangeable templates. It also sounds like you don't want to engineer that right now. I don't blame you. Another option is to create a one-off template sled. A big, heavy sled that keeps you away from the bit is a big confidence builder.

I was using a Woodpeckers Ultra Shear up and down cut combo.https://www.woodpeck.com/ultra-shear-half-inch-spiral-compression-flush-trim-router-bits.html Just the bearing on the one end of the cutter.
I did see an 1-5/8 inch length 3/4 diameter ultra shear with the bearings on both ends of the cutter. I might have to get that one eventually if I want to be able to flip the boards

Sounds like a jigsaw method is better than the full send method. Also sounds like using a sled with lots of mass is a good idea. I expect I will do these types of cuts on a regular basis. I think having a purpose built jig that can be reused will be a better option than a one off jig.
I was also using an old Porter Cable Speedmatic 7538 in my router table with a starting pin and some Grr-Rip Blocks if I had enough space on the work piece for Grr-Rip Blocks. The router doesn't sound as nice as my Festool OF1400 but that could just be how it is supposed to sound or maybe it needs new bearings. Online manual has a 2004 print date but I am thinking it could be even older. Maybe closer to 1990. I don't know if my uncle did any work on it when he gifted it to me. Its previous life was in his cabinet shop before he retired. I expect it got some major use before I got it.

I made 4 similar boards this past December. I jigsawed each edge close to my line. The guide line was made from my Shaper Origin using a 1/4 inch in diameter bit. I had no template. No Board had the same cutouts. Here is a picture of the one that was most prone to climb cut. After it unexpectedly tried to climb cut a few times when I was flush cutting I decided to borrow a spindle sander from a friend and finished flushing the board with the sander.