Is it safe to use a collet adapter with upside-down routers?

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BradyS

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Good day,

The title basically explains everything. I'm having a hard time after I accidentally purchased the wrong size extra collet for my Triton TRA001 (got a dupe 12 mm instead of buying the 1/4" one). I got a good deal on some 6 mm and 1/4" spiral router bits. Since I'm building my shop (in Romania), having to buy other collets and ship them to my country would delay me with another month. So I'm curious whether collet adapters like the ones in the link below could be an option.

My current setup is the TRA001 fitted to a dedicated Incra plate.

Moreover, I'd like to use some 1/8" bits for fine detailing (not in the Triton, in something smaller like a Makita RT0700 which I haven't purchased yet due to this issue). Makita doesn't offer a 1/8" collet either.

Collet Adaptor Shank Reducer Bit CNC Spindle Router 1/2" 1/4" 1/8" 3/4/6/8/10mm | eBay

So, the first question is how safe is it to use such adapters with upside-down routers?
Secondly, how safe is it to use such adapters with normally oriented routers?

Some advice from hands-on experience with these guys would be mostly appreciated.

Wish you all better days,
Brad
 
I use a Trend T11 in a table and nearly always use a collet adapter for 1/4" cutters - I find that to use the cutters it is otherwise sometimes difficult to have them pushed fully home and get the cut height I need, and the length of exposed 1/4" shank required is longer than I would like. Using an adapter allows a shorter length of exposed 1/4" shank because the adapter sticks out perhaps 5-8mm from the 1/2" collet.
 
I use a Trend T11 in a table and nearly always use a collet adapter for 1/4" cutters - I find that to use the cutters it is otherwise sometimes difficult to have them pushed fully home and get the cut height I need, and the length of exposed 1/4" shank required is longer than I would like. Using an adapter allows a shorter length of exposed 1/4" shank because the adapter sticks out perhaps 5-8mm from the 1/2" collet.
So that gives you an extra length. Didn't think of that, good point.
 
I make my own reducers and would never ever concider using the type shown in that eBay link.

Reducers should grip 'parallel' throughout their length, those are more like straight collets rather than reducers with the back end solid which means that they will only clamp on the front edge.

This is how I make mine, with one complete split along the full length and 2, 3 or 4 partial slots depending upon the size and amount of reduction.
Collet Reducer.png

This means that they will always deform 'parallel' and grip the tool along the whole length.

I have them for my Porter Cable Router Unit ½" to 12, 10, 8, 6mm & ¼" plus 8 > 4 - - (½" > 4mm is a bridge too far)
 
Last edited:
I make my own reducers and would never ever concider using the type shown in that eBay link.

Reducers should grip 'parallel' throughout their length, those are more like straight collets rather than reducers with the back end solid which means that they will only clamp on the front edge.

This is how I make mine, with one complete split along the full length and 2, 3 or 4 partial slots depending upon the size and amount of reduction.
View attachment 165751
This means that they will always deform 'parallel' and grip the tool along the whole length.

I have them for my Porter Cable Router Unit ½" to 12, 10, 8, 6mm & ¼" plus 8 > 4 - - (½" > 4mm is a bridge too far)

Truth be told, I made a mistake and realized it only when reading your post.
So the actual reducers are these ones

1693949118314.png


Bought from https://www.aliexpress.com/item/100...der_detail.order_detail_item.4.4b8df19ctOXTQh

These seem to have a similar profile except for the three slots instead of four.
It's amazing to have the ability to make your own (or have somebody able and willing to). I don't. And here nobody astes their time to fulfill custom orders of a few pieces. So this is the next best thing. I just wasn't sure if the very idea of 'reducers' is viable as a permanent solution. Meaning instead of using the appropriate collet.
 
These seem to have a similar profile except for the three slots instead of four.
The number of slots depends upon the size difference. The ½" to 12mm naturally only has the one 'through' slot, - a wall thickness of 0.35mm doesn't leave much space! - the 10mm has 1 through + 2 partial and so on.
It's amazing to have the ability to make your own (or have somebody able and willing to). I don't. And here nobody wastes their time to fulfill custom orders of a few pieces
Ah. . . having a metal-turning lathe (and the knowledge to use it!) helps :rolleyes:
 
I make my own reducers and would never ever concider using the type shown in that eBay link.

Reducers should grip 'parallel' throughout their length, those are more like straight collets rather than reducers with the back end solid which means that they will only clamp on the front edge.

This is how I make mine, with one complete split along the full length and 2, 3 or 4 partial slots depending upon the size and amount of reduction.
View attachment 165751
This means that they will always deform 'parallel' and grip the tool along the whole length.

I have them for my Porter Cable Router Unit ½" to 12, 10, 8, 6mm & ¼" plus 8 > 4 - - (½" > 4mm is a bridge too far)
Most high quality collets have a different slot cuts scheme: The slots are cut from an end and stop close to the other end, and the slots are cut alternating the slot open end... The design you are showing does have a higher Runout, because the clamping has only one slot open at only one side. A better design has at least four slots that run from an open end and have a short lenght not cut open, alternating their orientation; the very best ones for routers, have eight slots alternating the open slot end one towards one extreme and the next one having the open end of the following slot open towards the other end of the collet (or reducer) Thus, the collet or reducer has many "fingers" that uniformly clamp the shank of the bit,
foto reductor Amana.jpg
centering it much more precisely.

The photo shows an AMANA brand reducer intended to hold 3/8" bit shanks into a 1/2" router collet, you can see that the slot on the upper side of the image runs open from the left end of the reducer, until close to the right side, but stops short of the end, while the slot on the bottom of the image runs from the right side end of the reducer towards the left side, but stops close to the left end, therefore the four slots alternate in their solid unopened lenght that keeps the reducer in one piece. An 8 fingered collet would be still better in respect to centering and lower "runout", but both the four-fingered and the eight-fingered designs are better than a single slot collet or reducer. By the way, my cheap Bosch GF-550 trim router has a single slot collet, being a cheap design made in China and sold under the Bosch name... But my cheriched METABO straight grinder and my Milwaukee 2 1/4 HP router both have 8-fingered collets, and both exhibit lower runout, about one third of the single slot collet on my Bosch trim router...
 

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