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How to replace a cutter on a wood router (cordless and corded versions)

Find me something more annoying than changing a router cutter. It doesn’t matter if it’s a tool you’ve found buried in the workshop or your usual router cutter. You’ve slackened off the collet but the bit still won’t come out. There’s a few reasons this happens but primarily it’s down to being literally bound in there from either overuse or fused from a bit of rust.

If that’s not your problem and you are literally having trouble just removing the router cutter then no worries I am going to look at that too for you.

The first thing to know about a router is there is no set collet spanner size. I have power corded wood routers (half inch) with a 22mm spanner as well as a 24mm spanner – the Hitachi – what a piece of kit that is :).

I then have a Makita cordless router which I absolutely love (if you click the link you’ll see) and corded quarter inch routers using far smaller spanner sizes.

My router collet is really stiff and won’t budge – what to do?

Good old penetrating oil is your friend here. WD-40 is the choice of attack. Spray it and forget it for 24 hours, allowing the oil to run down behind the collet. Amazingly, this does work. However you need to ‘break’ the seal still. The way to do this is a damn firm hit on the spanner once you have the shaft lock engaged. If it still won’t budge it then becomes a job that is higher risk to the tool; hold the shaft lock in with a set of mould grips. Get a good firm grip on the shaft lock and you’ll then have two hands to get this collet free. A word of warning, if you have a plastic collet button, forget having a button after you’ve done this 😀

What we are talking about here is a last resort if the thing is completely seized. Definitely try to use oil and the correct technique first. This method will work, in fact I’ve never seen it fail, even on machinery far larger than we are discussing here but you want to be careful and realise the risk of damaging your router.

What if my router collet shaft lock to change the blade is not working or broken?

I don’t think there’s anything worse than being on site or at home for that matter, having to get a job done urgently and you can’t get the shaft lock engaged to change the router cutter. Eventually as you use your shaft lock (the button you push in that stops the shaft spinning) making a one spanner operation to remove the collet, eventually this fails from slipping or wear on the shaft. There’s only one real favourable solution for this – a set of mould grips. Absolutely as tight as you can get them, squeeze them in between the router and collet, with the toughest grip you can get on it. Yes, this will get you out of trouble once or twice, yes you’ll be over the moon and thank me now.

How to replace a router cutter – a look at the shaft lock

In time when you realise you’ve damaged the upper thread you won’t like me so much although this part of the thread isn’t engaged by the collet so no big loss, it’s not the ideal solution. You’ll need to replace the router shaft longer term unfortunately.

What do I do if I don’t have the right size spanner for my router cutter?

Measure. In one word, we need to workout a way that by the end of this you have a spanner, be it an adjustable or the right size that fits. It’s no good rushing off to toolstation for a cheap spanner set. I guarantee you the size you need is guaranteed to be missing 😀

Instead, let’s approach this sensibly. Place your tape over the nut holding the cutter (your collet) and get an accurate measure. Once you know what size spanner you need then it’s a case of buying an adjustable in this range or the exact size. There’s no magic bullet here, you need the right spanner for the job but be sure if you buy an adjustable it’s small enough to fit between the router housing and the fence. Some are too large – I know from experience sadly 😀

I’ve loosened the router collet but the router cutter is still jammed in there

Yeah that is a problem 😀 Sorry I had to…but don’t worry there’s a fix here. Basically it’s good ole WD-40 time again. What’s almost certainly happened is the router cutter has been pushed up in the collet so deep and hard its practically welded itself in there from prolonged use and heating binding it. This normally happens when you don’t change your router cutter all that often.

What you do is two things. Now you’ve sprayed the WD-40 you can give it a bit of a tap with a hammer. This will almost certainly be enough to break the seal and then put a set of mould grips around the shaft of the cutter and hit the mould grips downwards forcing the cutter out. Depending on whether or not the cutter is broken, you’ll need to decide where to place the mould grips.

Get a firm grip on your collet after giving it a good oil and push down hard

Let’s assume this didn’t work, you gave the oil 24 hours to really set in, followed the above to the letter etc etc. Now it’s time to put some heat on the collet. Heat it up. Don’t go mad, heat it up hot, not molten 😀 and then rapidly cool it. The expansion and contraction should well be enough to break the seal. If this doesn’t work it would be the first time in my life using a router (25 years nearly) that was the case and you’ll have to pop me a message for a solution with more exact pictures of the problem.

That goes for any other issues replacing or removing your router cutter. If there’s something I’ve missed then feel free to message me, I am sure to be able to help you 🙂