Spiral router cutters

[dm65]

I've been looking at spiral cutters today and it got me wondering (like most things do)

Am I right in assuming that if you have your router in a table you need an up cutter as this will actually pull the bits down away from the cut ?

If so, when would you use a down cutter ?

Regards

Den

 

[marcros]

As I understand it, up spiral brings the chips out of the hole, whichever way up the router is. Down spiral forces them in but gives a better surface finish to the entry hole of the hole.

 

[dm65]

As I understand it, up spiral brings the chips out of the hole, whichever way up the router is. Down spiral forces them in but gives a better surface finish to the entry hole of the hole.

So would be better for a through cut rather than say a trench ?

 

[Oryxdesign]

Spiral cutter can handle much higher feed rates than straight cutters. Up cut are the fastest down cut for a better finish.

 

[dm65]

Spiral cutter can handle much higher feed rates than straight cutters. Up cut are the fastest down cut for a better finish.

Have since read on Wealdons website that slow feed (that'll be me, one piece at a time on a router table) is quite damaging to these bits

Also read somewhere (Trend ?) that the down cutters are best for not producing tear out on the surface which seems to make sense

Thanks guys

 

[Oryxdesign]

one piece at a time is fine, just make sure you set yourself up well with good guards and whizz them through, obviously don't force it but try to keep up with the cut. I use an upcut on veneered mdf and still get a very clean cut.

 

[dm65]

one piece at a time is fine, just make sure you set yourself up well with good guards and whizz them through, obviously don't force it but try to keep up with the cut. I use an upcut on veneered mdf and still get a very clean cut.

I'll bear that in mind, thanks

Already ordered traditional two flute cutter now though, the fact that it was less than half price of a spiral cutter helped make the decision but I'll remember this for when I replace it

 

[Oryxdesign]

The spiral cutters are expensive because they are solid carbide rather than carbide tipped.

 

[Ian]

I came across this company http://www.cutweltools.co.uk/home/routing-tools when needing milling cutters and they have now introduced router cutters, I have tried their downcut HSS spiral and the results were fantastic and also they were about £12 each!

Worth looking at.

Best

Ian

 

[siggy_7]

Have since read on Wealdons website that slow feed (that'll be me, one piece at a time on a router table) is quite damaging to these bits

Slow feed is damaging to any cutter, in particular carbide ones. If you feed too slowly, the cutter will essentially be rubbing against the wood at high speed rather than taking decent chunks, i.e. lots of friction. The slow movement along the workpiece further encourages the build-up of heat. Whilst tungsten-carbide is a very heat resistant material (as well as being very hard), the binder used to hold the particles together isn't. The breakdown of the binder is what causes carbide tools to blunt, which is much exacerbated by slow feed rates. That's one of the main reasons why you should take repeat passes at a higher feed rate, rather than slow and heavy passes. Spiral bits may be more affected by this.

 

[dm65]

Slow feed is damaging to any cutter, in particular carbide ones. If you feed too slowly, the cutter will essentially be rubbing against the wood at high speed rather than taking decent chunks, i.e. lots of friction. The slow movement along the workpiece further encourages the build-up of heat. Whilst tungsten-carbide is a very heat resistant material (as well as being very hard), the binder used to hold the particles together isn't. The breakdown of the binder is what causes carbide tools to blunt, which is much exacerbated by slow feed rates. That's one of the main reasons why you should take repeat passes at a higher feed rate, rather than slow and heavy passes. Spiral bits may be more affected by this.

Cheers Siggy

I already thought I was being too gentle, but am new to this so I will remember what you've said

The reason I've been looking at the spiral cutters is that when I've made some practice cuts, the groove is often full of waste and has to be cleaned so I thought that the appropriate up/down cutter would clean as it went

 

[No skills]

Far to late to this party but I remember there being a company making triple or quad fluted cutters, might be worth looking at come replacement time. Hopefully one of the forumites can remember the company name.