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View Full Version : How to use 1/8" bits in my 1/4" bore router?



RomanLini
02-09-2010, 07:09 AM
Hi, I asked this question in the "Wanted to buy" section of the forum, but didn't get a good solution yet. I'm reposting it here in the hope that someone will have an answer, I hope that is ok.

My router is an Australian brand small router with 1/4" bore. I have 1/4" tools but I also have a lot of Dremel etc 1/8" specialty bits. These measure in shank size from about 3.05mm to 3.30mm, I guess the 1/8" is a bit relaxed with some manufacturers.

Is there an easy/cheap solution to allow me to use these 1/8" bits in my 1/4" router? The collet in my router is about an inch long and has a tapered section on the front third of it's length.

Something that would be ideal (to my mind) would be like a little Dremel chuck that could take the 1/8" bits (and even 3/32" bits) and the rear of the chuck would be 1/4" to slide straight in my router.

So if anyone knows a solution like that, or can recommend something that would work please let me know. :)

jjobezo
02-09-2010, 07:47 AM
Hi, I asked this question in the "Wanted to buy" section of the forum, but didn't get a good solution yet. I'm reposting it here in the hope that someone will have an answer, I hope that is ok.

My router is an Australian brand small router with 1/4" bore. I have 1/4" tools but I also have a lot of Dremel etc 1/8" specialty bits. These measure in shank size from about 3.05mm to 3.30mm, I guess the 1/8" is a bit relaxed with some manufacturers.

Is there an easy/cheap solution to allow me to use these 1/8" bits in my 1/4" router? The collet in my router is about an inch long and has a tapered section on the front third of it's length.

Something that would be ideal (to my mind) would be like a little Dremel chuck that could take the 1/8" bits (and even 3/32" bits) and the rear of the chuck would be 1/4" to slide straight in my router.

So if anyone knows a solution like that, or can recommend something that would work please let me know. :)

Try the 4486 Dremel Keyless Chuck. It replaces the regular chuck on dremel tools but I am sure you could make an adaptor to allow you to mount it on a 1/4 inch router.

SanDiegoCNC
02-09-2010, 07:54 AM
Good luck finding an adapter. The wall thickness would be no more than 0.060 . I'm betting you'll either have to machine a bushing... not a collet, or make a whole new mandrel that will accommodate your smaller tooling. Just out of curiosity, what target price are you willing to pay for a bushing/arbor or a new mandrel?

Andre' B
02-09-2010, 08:11 AM
Have you called the manufacturer to find out if they have different sized collets?

Look like any of these?
http://gpcollets.com/allProducts.html

And some adaptors.
http://gpcollets.com/adapter_cross.html

mcphill
02-09-2010, 11:50 AM
Good luck finding an adapter. The wall thickness would be no more than 0.060 . I'm betting you'll either have to machine a bushing... not a collet, or make a whole new mandrel that will accommodate your smaller tooling. Just out of curiosity, what target price are you willing to pay for a bushing/arbor or a new mandrel?

How 'bout this?

http://www.mcpii.com/Nicknacks.html#anchor_96

RomanLini
02-11-2010, 10:21 AM
Thanks for the info guys. :)

Andre'B- I checked that web page for collets and adaptors, none of the collets look exactly like the one in my router. I've posted it's collet dimensions in the thread in the wanted part of the forum, hopefully precise bits will get back to me with some more info if they have a compatible unit.

Apart from that it's in limbo at the moment. I might lathe up a brass version of my collet that has a 1/8" bore and a 3/32" bore to hold the 2 main sizes of Dremel bits, the good HSS bits have good shank diameter tolerance and the dodgy 1/8" sizes are mainly aftermarket bits like diamond bits and some burrs etc.

I'm still thinking about cutting the shaft out of a Dremel type tool and cutting off the last 1.5" that has the dremel collet chuck and turning the shaft down to 1/4". That would be good as I have a range of tiny Dremel collets going down to PCB drill size, so functionally it would be like putting the Dremel in my router.

SanDiegoCNC
02-11-2010, 10:54 AM
Thanks for the info guys. :)


I'm still thinking about cutting the shaft out of a Dremel type tool and cutting off the last 1.5" that has the dremel collet chuck and turning the shaft down to 1/4". That would be good as I have a range of tiny Dremel collets going down to PCB drill size, so functionally it would be like putting the Dremel in my router.


I'd be quite careful doing this. Routers run at high RPMs.You need to indicate the shaft withing a few tenths or its going to vibrate at high speed. That vibration can lead to all sorts of nasty things happening to you or your machine tool.

Be aware that you will need to machine a few thousandths at a time on your OD and watch for tool deflection on the shaft. I'd go for a very sharp insert tool when machining the shaft... perhaps a CNGP43.0 (0.007R) or an NPR (0.004R) insert. Keep the OAL short. Just a few tips should you decide to go this route.

:banana:

diecutter
02-11-2010, 01:27 PM
I'm using a 1/4" to 1/8" adapter made by Rotozip for their Rotozip tool. It's inexpensive, well made, and is rated for high rpm. The cutter is secured by an allen set screw and the 1/8" cutter is a snug fit in the bore of the adapter. I did not see any negatives when using it for what that's worth.

monte55
02-14-2010, 03:12 PM
This is what I did. Hope it helps.
http://www.millerwelds.com/resources/communities/mboard/showthread.php?t=20315&highlight=collet

RomanLini
02-16-2010, 06:17 AM
Thanks SanDiego, I still think a Dremel chuck would be ok if I can make sure it has low runout and is mounted close to the router nut.

monte55- I ended up making 2 adaptors for now, quite similar to yours. One is 3/32" and one is 1/8" so they can do most of my better Dremel bits.

I used some 1/4" aluminium rivets that were in my junkbox, and trued them and drilled them. Then they are slotted totally on one side, and for 3/4 of their length on the other side (also like your adaptor! Great minds think alike haha). Because they only have a very small skin holding them they conform well to both the bit and the router bore. Maybe the soft alloy helps there too.

My dial gauge easily measures the 0.0003 runout of my lathe, and these were made at zero runout (past the limits of my dial gauge) and they maintain this even in the router.

I cut some very fine engraving today with the small bit, it was holding a .003 line easily.

Thanks again everyone, for the moment I am right for 3/32" and 1/8" adaptors. I would still like a Dremel collet chuck though to use my range of Dremel collets and for things like PCB bits and non standard 1/8" shank diameters.

Walky
08-07-2010, 02:42 PM
If someone finds this useful, I've been using this adapter and it has served me well:

http://cgi.ebay.com/ADAPTOR-CHUCK-ADAPTER-1-4-MINI-DRILL-PIN-CHUCK-3-COLLET-/350266611748?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item518d845824

Very low runout (unnoticeable by eye), enough for SMD. The thread is very strong, and 1/8" tools fit very tightly in the adapter (sometimes a little too much, I need to use pliers to get some tools out sometimes). I broke one of the internal collets once (my mistake, shame on me), and bought a new one and a spare just in case: the runout is still very low :D

I've cut wood (2-3mm doc) and aluminum with it (~ 0.15 DOC). The smaller collet fits dentist's tools, which is nice.

Here's a video I made using this adapter:
YouTube- ‪Grabado de PCB en fresadora CNC‬‎

ger21
08-07-2010, 02:54 PM
Didn't realize this was an old post, but you can also use these.
http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bushing_ball_bearings.html

RomanLini
08-09-2010, 01:31 AM
Thanks for the new links everyone. :)

The soltuion I ended up with was to hand-make collets on my little lathe that go direct into my router and replace its nasty Chinese collet.

My collets take a couple hours each to make in steel, but I take the time to get them to low runout, and I also extend the body of the collet right down the shank of the tool so they are very rigid, ie only the cutting end of the tool sticks out of the collets.

I've made many sizes including 1/4", 6mm, 1/8", 3mm, 3/32" etc and they work very nice, surprisingly the inner bore of the router shaft is quite good with very little runout, so making collets to fit direct has been a good solution although it takes a little time. :)