Wood Router, Snapping Cutters

[routercnc]

I was cutting a load of 25mm MDF a while ago with a 6mm cutter like the one in the first post. About £3-£4 I think on eBay. I broke one about every hour or so until I swapped to an 8mm cutter and had no problems. The 6mm bits have that tapered section and this is exactly where they broke. The 8mm bits don't have that and the main body is straight with the cutting bits sticking out welded to the sides. Without that stress raiser that seems to make them more durable and with the thicker body they probably vibrate less. Worked for me . . .

[mike os]

what does it sound like when it cuts? i am wondering of your feed & speed are causing resonance in the cutter

[gorbo]

I use these cutters in Ply, hardwood and MDF, yes I have had some break ( I use 3mm single flute), but I found they cut better and broke less at a higher pass speed and lower RPM, I found at a low pass speed they over heated and snapped clean off, just a thought

[Tenson]

I just got some of the 1/8" (3mm) dia. single-flute cutters from toolstation for cutting 9mm birch ply. I'll let you know how it goes. http://www.toolstation.com/shop/p67412

Before these, I've been using 3mm 2-flute solid carbide. I've cut for hours on end with no problems. I've run 13000rpm and 2000mm/min and also 18000rpm and 4000mm/min. Both 4mm DOC. http://www.ebay.co.uk/itm/5Pcs-3-175...item5422121974

However I wanted something with a thicker shank so I could extend it further out the collet for various reasons.

I've used spiral flutes but up-cutters leave a horrible finish on the top edge. Down-cutters make it difficult to leave a constant thickness skin on the bottom cut to maintain vacuum.

[gorbo]

I just got some of the 1/8" (3mm) dia. single-flute cutters from toolstation for cutting 9mm birch ply. I'll let you know how it goes. http://www.toolstation.com/shop/p67412

Before these, I've been using 3mm 2-flute solid carbide. I've cut for hours on end with no problems. I've run 13000rpm and 2000mm/min and also 18000rpm and 4000mm/min. Both 4mm DOC. http://www.ebay.co.uk/itm/5Pcs-3-175...item5422121974

However I wanted something with a thicker shank so I could extend it further out the collet for various reasons.

I've used spiral flutes but up-cutters leave a horrible finish on the top edge. Down-cutters make it difficult to leave a constant thickness skin on the bottom cut to maintain vacuum.

I have brought some of those cutters too from Tool Station, see how long they last, I tend to use 3mm more than anything else

John

[Tenson]

Got some cutting on them today. I was about to post that they are working well and then SNAP!

I got about 2 hours continuous use on it. Birch ply @ 4.5mm DOC. Partly 2000mm/min at 16K RPM. Partly 4000mm/min at 20K RPM. Broke on a 4000mm/min 4.5mm DOC pass. Perhaps I'm asking too much of the little thing.

It worked well right to it's last breath. Cheap as chips so not too annoyed.

https://goo.gl/photos/KEqAuwNygLijbgoH7

https://goo.gl/photos/QNcDwZJaf82N3Lfm9

[Tenson]

I note however, that the red paint rubs off which means it is rubbing on the wood. This part of the cutter should be slightly under-sized so only the blade comes in contact with the wood. Perhaps this causes the heating and breakage? Maybe I'll sand it off first and see how long it lasts.

[gorbo]

I note however, that the red paint rubs off which means it is rubbing on the wood. This part of the cutter should be slightly under-sized so only the blade comes in contact with the wood. Perhaps this causes the heating and breakage? Maybe I'll sand it off first and see how long it lasts.

I would lower the DOC to 2mm and try again, you can`t expect top notch cutting from a cheap bit

[Tenson]

You are probably right but the job will take longer so I'll just throw cutters at it when they cost almost £1 each.

[Tenson]

To be fair GWizard suggests a DOC @ 2mm with 4000mm/min and 20K RPM.