Query about circ saw on a 'bot

[johnm]

Folks -

I recall someone setting up a circ saw on their Z axis for ripping a mess 'o hardboard - found the tread, but haven't gotten a response from the poster (Paul...."X" I think it was)

I need to cut scoring lines - miles of them, in hundreds of sheets of particle board with melamine. The scores are .090 wide and .150 deep - I figured I'd get better cut quality with a reground narrow kerf blade rather than the expense of a custom .090 bit, or a few dozen of them. I want to do the scores in a single pass, rather than use a .625 bit.

Any ideas, remarks, cautions?

Thanks!

John

[johnm]

Folks -

A follow up on this... I think I would use a small 4.5" grinder and a trim saw blade - I can get one of the same diameter. It looks like I could suspend the grinder vertically on the Z tower and that this would fit better than the horizontal configuration of trim saws and standard circ saws.

What about the return springs? I'd prefer not to have to remove the spindle, but build the saw carriage to allow easy detachment and have it so the saw blade was below the end of the spindle. Ideally, I'd have the offset between the center of the collet and the center of the saw blade some even figure, so that the calcs for figuring out where the saw was didn't get too "mathy"...

Thots?

TIA,

John

[harryball]

Sounds like a project indeed.

FYI, Onsrud makes a 3/32" bit which is very close to your spec. of .090, being .0937 in diameter. It is part# 10-01 and it should retail for less than $8. It's of HSS not carbide but it's something you might look at.

I run 1/8" grooves every 1/2" about .10 deep into full sheets of ACX plywood. I use a 1/8" carbide bit and run at 12 ips on my Alpha.

Robert

[johnm]

Robert -

Thanks, but the 3/32 bit is too big. Gotta be .085 or .090 max

John

[bleeth]

For the difference John, you can get the bit and have it ground. I bet Onsrud would do it for you.

[johnm]

Dave -

Yes, in fact, I am getting a quote on that. But my point is, I think that for as much as I need to cut, I could get better speed and cut quality with a narrow sawblade. Plus, predicting bit life in quoting the job is sketchy at best...

John

[davidallen]

I put a Skil saw on my PR several years ago.

I used it strictly to rip pieces of ply. On that model, I used a mounting fixture. A carrier with the tool was mounted on a holder. Each tool used a different carrier. The idea was you could switch out tools easier while still maintaining alignment.

The saw required a custom carrier but tools like drills, grinders or routers could use the standard design.

The grinder with a saw blade may or may not be a good idea. If there's a lot of flex and you don't get the blade square to the direction of motion, at best you'll get a bad cut. When a high speed saw blade shatters, you get shrapnel. Unlike a bit which is just 1 piece.

There are small panel or trim saws that run at more reasonable speeds. Remember, since you're not using the foot plate, it can be removed and the saw mounted at any angle.

You may also want to consider if you really need a z-axis. Once you get the depth set, do you need to change the height? you could just run off the end then move in the y direction to make the next pass.

If you can keep the saw guard in place, It makes a nice mounting support for the vacuum hose.

da