End mill length needed for cutting through 1.5" hardwood

[sakle2k]

I just got a couple of jobs that will require cutting through 1.5" thick cherry. The .25" endmills I have only have a cutting length of 1.25". Will they be ok to cut all the way through since the kerf has already been cut?

[Pete marken]

Even though the kerf is cut, there will be no way for the chips to evacuate the cut. This will probably cause excessive heat build up.

[sakle2k]

Even though the kerf is cut, there will be no way for the chips to evacuate the cut. This will probably cause excessive heat build up.

I'm assuming you're saying that as when the bit has cut down the 1.25", there won't be any cutting edge left at the top of the cut to pull the chips out, is that correct? If so, then a bit with a longer cutting edge would solve that. My thought was to use a down cut bit to start and then switch to an upcut. Does this sound right? Are there any bits that are long enough that you might recommend?

Thanks!

[gtgmarine]

I recently cut some HDU that was 1.5" thick with an extra long 1/4" bit with a 1.5" CL. As Pete said above, the chips had a hard time getting out of the cut once the depth was over 3/4". In my case I had to pause the job and run an allen key through the kerf to clear the chips up and then vacuum them out.... and this was with HDU foam.
You could do the same thing or maybe try using a long 1/2" up-cut or compression bit. Pricey but the wider kerf might make it easier to get the chips out.
Good luck.

[Jim Becker]

You an buy a relieved shank .25" endmill that can do deep cuts but these were primarily designed for materials like foam. You will likely get chatter and you cannot do a "final pass" since the LOC is far shorter than your full depth of cut. I have one of these and tried to use it for cutting out guitar bodies, but switched to a .375" endmill with a 1.75" LOC for these deep cuts.

[sakle2k]

Thanks guys, I appreciate the feedback. Glad I asked before trying this, I hadn't considered the issue of evacuating the chips. I'm gonna have to think this through.

[Charlie_L]

I’d call Joey at USRouter tools for ideas.
I have used 0.5 inch tools with lengths from 1.5 to 2.5 inches.

[sakle2k]

I’d call Joey at USRouter tools for ideas.
I have used 0.5 inch tools with lengths from 1.5 to 2.5 inches.

Good idea, thanks.

[sakle2k]

You an buy a relieved shank .25" endmill that can do deep cuts but these were primarily designed for materials like foam. You will likely get chatter and you cannot do a "final pass" since the LOC is far shorter than your full depth of cut. I have one of these and tried to use it for cutting out guitar bodies, but switched to a .375" endmill with a 1.75" LOC for these deep cuts.

Thanks Jim, good to know what worked for you. Did you use an upcut or down cut bit on the guitars?

[Jim Becker]

Thanks Jim, good to know what worked for you. Did you use an upcut or down cut bit on the guitars?

The specific cutter I have is an up-cut, Cobra brand off Amazon, and very reasonably priced. I consider it a specialty cutter and it's fine for the purpose. I'm also not a production shop. In addition to the guitar bodies, I've used it to trim slab ends and other utilities like that where the material is thick. I generally cut with a small allowance (.02-.03 mm usually) and do a last pass to clean the edge.

[rcrawford]

1/2" endmills cut better in hardwoods than 1/4", especially if you are cutting 1.5". Its counterintuitive, but the larger endmills actually cut easier than the 1/4" in hard woods.

[sakle2k]

I picked up an Amana Tool 46323 SC Spiral Plunge 3/8" upcut. Went through it like it wasn't there, lol. I did follow the cut to manually clean chips left in the kerf but worked out well, thanks again to everyone.
Russell, I will pick up a 1/2" at some point.