Alternative to sleeve adaptor for router collet

[siggy_7]

I am planning to buy a 3/8" carbide end mill for cutting deep mortice joints with my router, a Triton TRA001. The Triton only has 1/2" and 1/4" collets, and I can't find a dedicated 3/8" collet. As the cutter is long and will be working hard, I don't think using a Trend sleeve is a very sensible idea. I had an idea that I could cut a right hand thread on the end of the shank, and machine a steel sleeve to screw over this on the lathe, with a precise outside diameter of 1/2". The cutter's action should act to tighten the sleeve on the bit, so shouldn't come loose. Is this a good idea, and will the results be more secure than a collet sleeve?

 

[9fingers]

I reckon the cutter will chatter inside your sleeve as the shank will not be gripped at all.

Bad idea in my book. Buy a 1/2 shank 3/8 cutter. Try Wealden such as TX1409.5M

Bob

 

[siggy_7]

Thanks for your reply, sounds like it might not be such a great idea after all then.

My reasons for wanting to try this are several:

1. I'd like a spiral fluted bit for cutting deep mortices
2. Spiral fluted router bits are rip-off expensive compared to end mills
3. Router cutters, including spiral bits, have much less reach than long end mills

E.g. Wealden's 3/8 spiral bit is £50 and is limited to a 31mm deep cut. Adequate for most operations granted, but there will undoubtedly be times where I will find that a limitation.

See http://www.finewoodworking.com/item/20779/end-mills-vs-router-bits-for-mortising for more info on why I'd like to use end mills.

 

[9fingers]

OK if you want to use end mills then you need something a bit like a Clarkson Autolock collet. i.e. a thread to locate the end of the cutter at the back and a split sleeve to grip the diameter of the shank.
Doable but needs careful machining.
Before you get too involved in the collet making, check the cutter shank to see if you can cut a thread. After the cutter manufacture, those shanks are likely to be tougher than a whore's heart.

Those cutters shown in the FW article are solid carbide - not a cats chance of threading those - you might be able to find some ready threaded 20tpi for milling chucks

Bob

 

[jasonB]

You won't cut a thread in a solid carbide cutter.

Carbide router cutters have a completely different geometry to allow them to clear the chips faster than a slot drill/endmill

And on a safety note solid carbide cutters are very brittle, drop one on the floor and it will shatter, with a router even in a table you can't control the feed like you can in a mill so there is a risk of snapping the long cutter, they make the router ones short for a reason.

J

 

[Racers]

Hi,

I have a couple of adaptors made for 6mm and 10mm shanked end mills made for my 1/2" routers, just like a 1/4" to 1/2" adaptors. they work very well. screwed or ones with a flat on them work fine as long as you don't try to clamp on the screw of flat.

My most used 1/4" milling cutter is a solid carbide one it works very well and it has stayed sharp for ages.
End mills are very cheap compaired to router bits, you can get some bargins from the USA.

So just make a adaptor that had a 1/2" od and 3/8" id and cut a slot and off you go.

Pete

 

[siggy_7]

Thanks for the advice everyone. I think I'll try a collet sleeve and see how I get on, unless my searchign luck changes and I find a proper 3/8" collet.

 

[jasonB]

One other thing to remember is that a typical "endmill" will not be suitable for plunge cutting so not a lot of good for mortices. You need a two flute cutter which is generally in the UK termed a "slot drill" these have the end of one of the flutes ground long enough to go across the centre so they can plunge cut.

There are exceptions, just look for cutters that are termed "endcutting" or "centre cutting"

Oh and just been looking through a couple of my engineering supply catalogues, you won't get much change out of £50 for a long series 2-flute solid carbide cutter.

J

 

[Racers]

Ebay.com is loads cheaper even with postage

http://www.ebay.co.uk/itm/NEW-1-2-4-FLU ... 2c5e7e1e1f

I agree about slot drills they are better for mortaces.

Pete

 

[jasonB]

But you do get what you pay for. I use the "cheap" cutters for general work and good quality FCY cutters for small items and keep my decent Dormer ones for jobs that matter both HSS and solid Carbide.

This is a good source for cheapies.
http://richontools.com/index.php?main_p ... x&cPath=15

And don't forget its not just postage to add to those prices, there will be import duty, VAT and the post office charge.

 

[siggy_7]

I liked the look of these cutters myself, should cut nice and deep when necessary (and also the long flutes will be ideal for jointing thicker material on the router table) :

http://www.ebay.co.uk/itm/300402937...AX:IT&_trksid=p3984.m1438.l2649#ht_500wt_1054

The also sell a 4" long 1/4" cutter with 1.75" flute length, and a 1/2" cutter the same length as the one above. Need to check if they are centre cutting, but the images look like two of the flutes extend to the centre. Slot drills generally don't cut flat bottomed holes, in my experience a cutter that is capable of plunging that cuts flat bottomed is usually called a centre-cutting end mill rather than a flat bottomed slot drill, although both are correct terms.

I've used mostly Wealden cutters in the past and been very happy with the quality, but their 1.5" flute length 1/2" two-flute up cut spiral bit is £72. With solid carbide end mills from the states around half that price (and built to cut steel all day long) I don't see the logic myself.

 

[Andy RV]

One option is to use the axminster collet extension which uses standard ER20 collets which are available a wide range of sizes, then buy yourself a 3/8" collet for it.

http://www.axminster.co.uk/axcaliber-router-collet-extension-(1-2-shank)-prod804844/

 

[siggy_7]

Thanks Andy, that's a great idea. I'm a bit worried about the leverage of a long bit in combination with an extension collet, but I guess it will probably do a better job than a 3/8" sleeve.