Single flute carbide cutters

I'm thinking that they may not be as effective as a 2-flute cutter at plunging since with only one flute cutting (instead of one and a bit) the direction of the resultant force in the X/Y plane is going round in circles. Whereas with 2-flute I imagine the the forces are almost equal, and they are opposite ... so they should at least partially cancel out. That does not take into account swarf ejection though...

We used carbide 2-flute cutters (2mm and up) on the little router at school all the time with various plastics. They lasted a long time.

So do these single flute carbide cutters on ebay have a centre cut for plunging?

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Originally Posted by Karl

So do these single flute carbide cutters on ebay have a centre cut for plunging?

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the cut passes the centre and because of the rake and clearence etc if you plunge a blind hole you end up with a small dome at its base

make sure you measure the radius of your cutter when you buy them !!!!
mine sold as 3.175mm however the cutter was much closer to 3mm and the shaft was 3.175mm..... took me ages to work out why some of my parts were under/over sized:whistling:

I have tried several of these single flute cutters and results vary relative to the quality. You can buy them in solid carbide from US$ 4 to US$ 60, in HSS from US$1 to US$ 10. This price is for a 6mm cutter.
As blackburn mark mentions, measure the exact diameter. Especially the cheaper ones vary slightly (some up to 0.1mm).
I can plunge even the cheap ones in aluminium at twice the speed than 2 flute milling cutters without any vibration. I have cut solid hardwood, MDF and acrylic with great results and performance in aluminium is even better. And it does not die if it takes a chunk out of your vice either. I use them on my router and my mill.

If you thought your router would be not solid enough to cut aluminium, give these a try. You could be up for a nice surprise.
On my home made router I cut 16mm MDF in one cut at 400mm/min @ 12000rpm.

The cutters arrived ... and they're excellent! Not measured the diameter yet as my sister has borrowed my micrometer (long story).

I've only used one so far, and on aluminium. Cut some lots of parts from 4mm aluminium sheet with 0.5mm depth of cut and no coolant at 550mm/min ... no problems and left a good finish. I used a spiral path, so no plunging.

Also used one to cut two spindle mounts from 5/8" aluminium, again pretty good finish this time with 0.7mm depth of cut and cutting fluid. The swarf is ejected much better as expected.

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0.5mm depth of cut

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that doesnt sound like you jonathan !!

in acetal (like butter to cut) ill go up to 3mm depth with the 3.175mm cutter at 200mm feed and adjust spindle speed untill the chips are nice chunky curl and do a 0.5mm finish at full depth (upto 20mm)
i use a fish tank type air pump to blow the chips away... its a tiny amount of air but with the nature of acetal chips it doesnt take much to clear them even in a slot

they are quite good in abs as well, with the reports i had heard i was exspecting meling problems but i didnt get any of that, im guessing my spindle speed was aprox 2000rpm

iv snapped a couple of small single flute cutters in plastic when braking out of slots that arent perpendicular to the exit face, when the cutter exits the material it can pull itself out of the exit and try to walk around the corner .... pi**es me right off when its a fresh cutter, im guessing a lower feed or higher spindle speed would stop this but it seems to happen at what i would cosider the sweet spot (i might be overly aggressive:whistling:)

I think I'm going to buy some as I have no cutters for aluminium any guidance on sizes would be greatly received or should i buy a kit?? and add to it as and when I need it

James

Bigger diameter cutters are *much* more rigid, so you want to use the biggest you can for a particular part. Within reason though as clearly a bigger diameter cutter will remove a greater volume of material, so the cutting force is higher for a given depth of cut. It's a balance ... I thought 6mm was good in general, but if you're only cutting say 5mm sheet then 4mm would probably be fine. I wouldn't advise anything bigger than 6mm for a router.

I've got some 0.5mm, 3mm and 4mm on the way, though they are two flute (oops).

what about plunge cuts of flat bottom hole ??

James

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Originally Posted by Jonathan

I've got some 0.5mm on the way

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Blimey, you're brave :eek:

OTOH maybe you are cutting cheese or these are in stub length :naughty: