The hydra is a mythical beast, with multiple heads, and when one is lost, another grows in its place. I’ve never imagined I’d speak of the creature, the hydra, and router bits in the same sentence, but there you go.
In the past, router bits are a solid unit, with the sharp edge (tungsten carbide commonly these days) brazed to the body of the router bit. The science behind the brazing can be quite profound, allowing the brittle tungsten carbide survive significant abuse. These router bits can be resharpened, but you need to get them done professionally to achieve the best result. Tungsten carbide on cheap bits is dull, often even painted to disguise the (lack of) quality. I have also been told in the past that tungsten carbide is tungsten carbide, so cheap bits are the equal of the “overpriced other ones” Bullsh*t! Sorry, but I have been told that on more than one occasion, and I really wish those who don’t know (or don’t care) wouldn’t continue to spout such crap. It is like saying all diamonds are the same, and we know that is not true either.
Oh – bit of an aside – you may well ask, if carbide is so wonderful, why are there not diamond router bits? Might surprise you, but there are! There is diamond embedded in steel router bits, used to rout glass – such as putting a chamfer on glass. Even more recently, in the Amana Tool catalogue, there are polycrystalline diamond router bits, with an edge that lasts up to 200 times longer than tungsten carbide. Not sure why, but for CNC machines only. The Amana Tool catalogue is scary – sooooo many awesome router bits. Drool.
Ok, so we have established that some router bits (the most common) are all machined and brazed together. The cost of replacing the edge requires the replacement of the entire bit.
The next approach has been detachable carbide, held onto the bit with one or two (hex) bolts. Larger pieces of carbide is often used, thicker, and they can also use harder (and more brittle) pieces due to the thicker section, giving longer edge life. If something goes wrong, and the carbide breaks (or dulls from use), it is a very cheap replacement.
A few of my bits have replaceable tips, such as my surfacing bits. The two that have replaceable tips can be rotated to present 4 edges in total, providing significant life expectancy, and the tips are cheap even when they all do wear out.
Now the point of all this is there is another option. Replace the head! Its the hydra model for router bits!
It is a fascinating model, and there are some distinct advantages. I’d never heard of them before, but the guys at Toolstoday.com recommended them, and they haven’t steered me wrong yet :)
The tungsten carbide is brazed to the head, so the body of the head does not need to be as ‘chunky’ to support a threaded section to hold the tips on. The head can be machined so each tip is accurate, and the whole assembly becomes rather cost effective when you start running through the consumables. Not sure how much it matters, but exchanging the consumables is faster than replaceable carbides, as you don’t have to do each tip individually. They are called the EZ-Change Replacement Head router bits, and you can change the head while it is still attached, and set up in the router. This is particularly useful if running large jobs and you don’t want to have to recalibrate the setup because you’ve had to change router bits to get a sharp edge again.
There are two types here – whether you require the bearing to be below or above the cutters. The spare packs come with 3 replacement heads. The cost won’t kill a budget either – $US18 for the router bit (including a head), and a 3 pack of heads is $27 – less than $10/head.
What will they think of next?!