Used router / mill bits?

[DennisCA]

I came across a section in a local flea market that had a lot of different bits. I think they might be meant for metalworking rather than woodworking, I was curious though if the spiral bits could work in a wood router? 4-8 euros per bit which is cheaper than any spiral bits I've found, here's a 2 flute cutter which I understand is what wood router bits usually are but there where 3 and 4 flute cutters as well:

 

[marcros]

yes, as long as you can grip them. This tends to mean you are restricted to 1/2".

i have used an HSS bit on oak which gave an excellent finish. I havent used a carbide one, but it is worth trying given the price. Pete Maddox (I think) gave me the tip.

 

[pcb1962]

The 2 flute cutter in the first picture is a 'slot drill'. The 2 cutting edges on the sharp end should overlap so it can plunge as well as cut sideways. The 4 flute cutters are 'end mills', the 4 cutting edges on the sharp end most likely do not meet and so it cannot be plunged, only used for traversing into or across the workpiece starting from an edge.
I'll add a couple of pictures to show you what I mean when I get home.

 

[graduate_owner]

If you intend to use these in a 1/2" router then make sure you do get 1/2" cutters. They come in metric sizes as well and a 15mm shank won't fit correctly - unless of course you have metric collets for you router as well as 1/2".

I have used cutters from my milling machine on wood, but the miller does rotate much more slowly than a router. The cut is not as clean, although the cutter was very sharp, so it's probably the low speed that's at fault. I was using the set up to cut a mortise, so the finish was not important.

I'm not sure what would happen if the milling cutter was used at router speed, because they are not intended for such high speeds and may overheat - just a guess.

K

 

[graduate_owner]

If you intend to use these in a 1/2" router then make sure you do get 1/2" cutters. They come in metric sizes as well and a 15mm shank won't fit correctly - unless of course you have metric collets for you router as well as 1/2".

I have used cutters from my milling machine on wood, but the miller does rotate much more slowly than a router. The cut is not as clean, although the cutter was very sharp, so it's probably the low speed that's at fault. I was using the set up to cut a mortise, so the finish was not important.

I'm not sure what would happen if the milling cutter was used at router speed, because they are not intended for such high speeds and may overheat - just a guess.

K

 

[Hemsby]

The 3 types are designed for engineering use cutting metal etc the 2 flute is a slot drill is used primarily for plunge & slot cutting, using a full width x full depth cut.(can be used for axial cutting but not a preferred use)

The 4 flute end mill is used for full width cut but at a max depth of about only 1/3 of their diameter, or full depth x 1/3 width of diameter on an axial cut.

The 3 flute is just a compromise of the 2 & 4 flute, its plunge cut is poor compared to the 2 flute as is its performance against the 4 flute. It is a combination tool avoiding cutter change in production applications.

These figures & comments are for when used in metal.

As they will be HSS the 2 & 4 flute (not sure about the 3) will cut timber well, possibly with a degree of clogging, due to their spiral flute form

A new HSS cutter will produce a better finish than Tungsten Carbide in any timber, but will not have the life span of the latter.

I have run HSS small end mills at very fast speeds on CNC milling machines cutting aluminium but as with all cutting operations speeds & feeds are dependant on various factors, cutter diameter, feed rate, depth of cut and rigidity of work piece

If you look at speeds for HSS drills in materials such as Aluminium, brass & plastics they certainly don’t shy from fast speeds. Im sure if you look on the net you will get advice on speeds for use in timber.
Regards,
Keith

 

[DennisCA]

Thanks for the replies, and to answer graduate_owner, I have only an 8mm router for now, but they kindly provided a caliper to measure with (a mitutoyo even, wanted to buy it but it said not for sale) and I found several 8mm bits. Given the price I may get a 2 flute cutter and see how it performs then.

 

[siggy_7]

I use end mills for routing a lot - the spiral flutes give a much smoother cutting action and also clear chips a lot better than straight bits. They are also a lot cheaper than spiral router bits. I use a collet extender from Axminster with ER20 collets, these are available in any size up to 13mm and provide good grip over a 1mm size range (most router collets only give a secure grip on a very precisely sized shank). You can get end mills designed for plunge cutting - mine all are. You can identify this by checking the bottom face to see if there is a cutting surface that extends to the centre. Because they are flat they won't plunge as well as a slot drill, but I find they work acceptably for morticing.

 

[Claymore]

the price is pretty good, i used similar ones in my CNC and they were expensive to buy, never used them for wood so can't comment. Last year i went to a carboot and bought a job lot of "old tools" for ten pounds and after checking the contents found out they were worth £700+ and were from a small company who had gone out of business.

 

[Wildman]

be aware the spiral will pull itself out of the chuck unless very tight, even on brass