Thread: Is this bit too big for my router ?

Perhaps the real reason is that they are designed for use on a router table only?

If you're going to make comparisons, at least compare with something real, not the BS story you quote (see here).

Ray

This tit for tat is getting tedious.

I've got a box of Chinese 1/4"" bits that I bought for a few $ that are dangerous. It is criminal they are being sold. Two have self destructed under very light use. If you want to pursue safety issues perhaps it would be more constructive to target the idiots selling crap bits weekend warriors buy by the truck load rather than picking a case against a seasoned professional try a controlled experiment with a quality bit and due consideration to the potential risks involved.

Originally Posted by Fuzzie

I've got a box of Chinese 1/4"" bits that I bought for a few $ that are dangerous. It is criminal they are being sold. Two have self destructed under very light use.........

Just say (TM PL) more drivel than is useful.

Bit of bad luck on the purchase but what does (TM PL) stand for?

Originally Posted by Christos

Bit of bad luck on the purchase but what does (TM PL) stand for?

Sorry Christos, a lapse on my behalf. It's totally irrelevant to this forum. It's the end of a long week where a couple of things didn't work out quite right....

Originally Posted by Fuzzie

This tit for tat is getting tedious.

Agree and I've been overly guilty of indulging and let my emotions take over with unwarranted comments (apologies). Admin: maybe this post should be closed?

Originally Posted by sjt

Agree and I've been overly guilty of indulging and let my emotions take over with unwarranted comments (apologies). Admin: maybe this post should be closed?

Closing a thread is usually a last resort and things have calmed down a bit anyway.

Originally Posted by Groggy

Closing a thread is usually a last resort and things have calmed down a bit anyway.

Groggy

Agreed.

Adults should not need to be treated like mischievious children or miscreant adolescants, but this thread has come periously close at times.

I have to confess that this thread ultimately has left me quite disturbed and a little confused..

I found myself unable to distinguish between banter, sarcasm, tongue-in-cheek good natured humour and unrivalled silliness of the potentially dangerous kind. Now this may be a failing of mine. I have many failings and it came as a great shock to me the day my wife assured be she loved very dearly but said I wasn't "perfect!". All those delusional years...

There are two fundamental issues here to my mind. Can a large diameter router bit be used in a hand held router and can a large diameter router bit be used in a router that does not have variable speed?

Two quite separate questions: To take the second question first, the issue is tip speed. In a variable speed router spinning at 8000rpm an 81mm diameter bit peripheral speed will be a little over 2km/min.Compare this to a spindle moulder with a 100mm dia cutter which will be travelling at close to 3km/min.

The 81mm bit in a router without variable speed, and let's assume here that it rotates at 21000rpm, (it could be more) will be moving at over 5km/min (300km/h in your family sedan)! A router with it's modest 1/2 inch shaft is not built to withstand this level of abuse. There is every likelihood bits of the router and the router bit will find an affinity to your person. I don't like to think of pieces of copper, tungsten carbide and steel passing through through the very feeble skin and bone of the human. Yuk.

The spindle moudler with it larger shaft (19mm or 30mm) and more robust construction is a very different machine and able to withstand the centrifugal forces generated.

Now to the question of hand held. Many woodworkers reading this thread will be inexperienced with routers and will not be aware of how fearsome a large router can be. Just rotate (gently) a large router with the motor running and wittness the gyroscopic forces. We are talking about huge potential energy.

If a novice decides that it is acceptable to use large bits in hand held router he is potentially puting himself at risk and as responsible people we should not encourage that practice.

Let me quote a story of a friend who many years ago was racing a car and was on the same track during practice as Graham Hill. My friend asked the great Graham Hill what rpm he took particular corner at. GH replied 5000rpm. So my friend promptly tried this, spun off and crashed. He was unhurt and quizzed GH, who explained that he took the corner in fourth gear not fifth!

A little knowledge can be dangerous. Placing a large bit in a hand held router is fraught with danger.

This is the crux of my point about this thread. It is difficult to know who is jesting. In fact, I suspect there was a degree of jest initially and then suddenly offense was taken when criticism was too vitriolic to take in jest any more.

So, please, no large bits in single speed routers and for the vast vast majority of people no hand held routing heroics, but arguably that should be for everybody. I would not like to hear of any inadvertently sanctioned or condoned accidents.

Regards
Paul

Originally Posted by Bushmiller

Groggy

Now to the question of hand held. Many woodworkers reading this thread will be inexperienced with routers and will not be aware of how fearsome a large router can be. Just rotate (gently) a large router with the motor running and wittness the gyroscopic forces. We are talking about huge potential energy.

On that note, something I learnt while I was doing a wood machining course last year: a 2 gram imbalance in a four-side-moulder cutter block spinning at 8,000 rpm translates to 12kg of force on the spindle.

Even if you scale the imbalance down to compensate for the much smaller size, it's still spinning 3 times as fast.

Just a thought....

There used to be a door maker in High Street Prahran a number of years ago that I chatted to. He used to grind his own profile cutters for the router, freehand out of bar stock. It has always stuck in my mind how out of balance those bits would have been, but then again he had been doing it for years. It's always possible to get away with doing risky things, I personally believe bad habits have a cumulative effect that eventually results in catastrophic failure, sorta like Steve Irwin.

Then again, Sam Maloof used his bandsaw like a pencil - carving a piece of walnut like he was drawing on it. Having said that, I have many times used a 89mm panel raising bit in the router mounted in the triton table using the big triton router. I can vouch for one thing - the speed must be turned down on these large cutters to ensure safe routing. Even then a few passes gradually working toward the maximum cut is required for 1. safety and 2. a good quality cut. My tuppence worth.
Regards
Les

I wouldn't have done it if there was bad vibration, when I started up.
I wouldn't have done it first on a denser timber.
I wouldn't have done it without a wider base
I wouldn't have done it without a good quality bit, with sharp blades.
I wouldn't have not cautiously taken light cuts before deciding a one shot was quite possible.
I wouldn't have done it not wearing my safety glasses.
I would NEVER EVER EVER have done it just out of spite.

I don't think there's really any empirical evidence here on the true danger. Or will ever be. Some factors are being excluded with their fear statements. Like cutter and timber type. And feedrate is still as humanly inconsistant. And I'd say this is whats happening with most accidents. dangerous catches that pressure the collect. And this is still here regardless of whether or not its a router table or freehand.

some thoughts I've had as to why its not clearly ' very dangerous ' .....

At slower speed I believe your'll have more accidents on a router table (just because I don't have a router table doesn't mean I have no experience in it) than with the freehand method I described above. Because hands are not moving towards a cutter with freehand. with something like this I would feel far more comfortable doing this freehand (also keep in mind this cut is to be done on chair seats....inconsistant curved surfaces. Haven't got the stability of a router table fence. No powerfeed)

At higher speed, even though its throwing more weight, I believe the blades are less likely to catch because its cutting smaller amounts of material......and its the catches I believe, that have most significance when it comes to that grenade like explosion.....I bet the true stats on this (if ever to be worked out) would be very surprising to many here. To a point probably, in some circumstances its be more dangerous to have it at a slower speed. IMO.

with the round over bit, IMO, there's no sudden full blade contact. Don't really have full blade contact till the very end when all the stocks removed anyway. Meaning there's a lot of control. Creep up on it really easily. plenty of warning signs to stop ie. the type of profile is a big influence....cutting speeds vary along the blade....... I've got a flush router bit that I would think is far more taxing on the collect than this large round over bit because its cutting pretty much all the time with full blade contact. Can feel it pressuring the collect in not a pleasing way pretty much all the time. . YET, this bit runs well within the the safe speed settings thrown at me at the beginning of the thread. ..........

After trying it, IMO, there are far more dangerous practises that go on in a workshop (thats how easy I felt it was) . practises that would draw far less drama over, or considered even acceptable because they've been normalised.

I brought this up origionally because I wanted to hear someone tell me ....somehting like .......' jake don't do that. I made a setup like that, and even though it was good initially, after a week of constant use the router started developing serious vibration ' .........save myself a router and time spent on a series of processes relient on it. ........but now that I've done it, I'm sorry, but I just don't think its going root the router.