View Full Version : Bits ... the selection of bits, truth, myth, etc.

Thu 02 December 2010, 10:12
Well, I start this thread not to give advice, I'm not the right one, but .... having finished the MechMate, the next problem is ... make it works. To do so you need to lear the software and you need Bits to make practice.
So after searching on the forum for info and "google-ing" around, I contacted some producer here I report and share my info.

On the forum I have learned that solid carbide is the right choise, and better avoid HSS (source: Gerard)
It was difficult to find solid carbide for woods, but many reported that metal bits are ok ....
Three out of Three producer/distributor of solid carbide bits told me the same things: their bits are not suitable for woods, I insisted that I know it's ok to use metal bits, and those are the answers:
1) www.europatool.co.uk told me: "Our products are not suitable for wood, they are for metal cutting." after insisting they sent me their catalog.

2)HITACHI TOOL ENGINEERING EUROPE GMBH told me (after my insistence): Actual we donít have any mills which can be used in wood.
For wood you need sharp uncoated end mills. Our end mills are all coated.
Thatís the reason.

3) www.dhfitalia.it : Our mills are only for metal, their geometry is not suitable for woods.

Serching in the forum I saw tha Onsrud ave a choice of mills suitable for woods, but not that easy to find in Italy

then our friend "renraku" (Italian from Rome) told me he has a lot of CMT mills for wood that he bought locally.
It seems they have a good choice, there is a shop in rome where they sell only woodworking stuff and they have stock of them.
I bought some CMT I will report my inexperienced impressions.

It would be nice if others here corect me,and/or give their contribution to general knowledge. For example: can somebody tell the difference between straight, spiral, compression, upcut, downcut ..... ecc. ?

Thu 02 December 2010, 10:42
check out this site.


Thermwood is a very expensive device, but this supplies site looks like it has a lot of items focused towards us MMers.

Gerald D
Thu 02 December 2010, 11:03
Sergio, go and try the cheapest, 2-flute, up-spiral, solid carbide bit that you can find. Do not look at catologues. Tell the salesman that you are cutting aluminium if he really wants to know the material. He should find you something from under his counter with no name on it, that he imports from Asia. This type of cutter has been the most economical for us on cutting "wood" (MDF).

Thu 02 December 2010, 11:07
Thanks Mike very interessing site I have to study a bit !

Here there are many answer on the questions I posed in post 1 (upcut, downcut ecc) page 89 of the catalog.

thanks Gerard, on that multilanguage catalog with pictures even a "dummy" like me can understand (translation is important: upcut downcut ecc are difficult to explain to an italian salesmen, at least it's good to know better than him what he is trying to sell you :-) )

Sat 04 December 2010, 09:08

I've went down the exact same road you are traveling on now. I ended up using cheap MM straight bits that are about $2 dollars a piece and they have held up well with MDF. I use vac hold down so I avoid up-cut bits if I can. I've snapped a number of MM bits but the MM two flute straight bits work well for me. Good luck!

Gerald, correct me if I'm wrong but in my neck of the woods, bits designed specifically for aluminum tend to be more expensive than the average two flute carbide end mill. To my understanding, bits designed for aluminum have a very aggressive chip removal geometry. I use them quite extensively for cutting acrylic with excellent finishing results. I've never tried them with wood as they are a little expensive but I'll give a well used one a try.

Sat 04 December 2010, 09:22
Dave, I just got quotes from my friendly local hardware stores. Carbite bits for AL are expensive... but those Cr coated are really palatable... will this be good enuf for acrylic?

Gerald D
Sat 04 December 2010, 12:51
David & Ken, the last time I personally looked for bits (my son does that now) the local companies supplying cheap imported Asian bits did not have special Al cutting bits, so their cheapest bit had to do the job. And it did the job fairly well.

Sat 04 December 2010, 20:58
so their cheapest bit had to do the job.

My kind of approach :)

Sat 04 December 2010, 22:32
We have found single cutter straight bits to offer the best longevity.


We've tried upcut 2-flute solid carbide from bosch and a couple others whose names escape me at the moment. We've also tried 2-flute straight cutters. The single flute bit outperforms.

In 1088 marine ply, we run about 200ipm peak speed @ 20,000 rpm @.25" DOC.

If we had a spindle, or really huge ipm speeds we'd reconsider 2-flute designs.