.............. Does anyone have experience with this? My concern is that the bit is fastened with a hex-screw rather than a threaded nut. The other option I am considering is CMT 796.001.00 Router Collet Chuck Extension for 1/2-Inch Collets, 1/2-Inch Shank with the limitation that it accepts only 1/2" bits. Any guidance will be appreciated.
I have both. First I got the CMT one. I needed an extra 1" due to my table's thickness which I was unable to change. It frightened the heck out of me and due to it's length, the bit would not go below the table.
Then I found the Xtreme XTension. Wow, chalk and cheese. It worked great immediately, no fear, locked it into the router and used a straight bit immediately with a great result. It gave me the extra height I needed and it is transferrable to any 1/2" router. Using 1/4" bits is also no problem. Just shove in the 1/4" thingy with the slot in it's side lined up with where the allen screw goes through to tighten it. Then just tighten away.
I now have above table bit changing, so no need to go diving under the table.
I have read some users have experienced the allen screw breaking or rounding out after a time so they bought stainless steel ones. I got 4 stainless steel ones and replaced mine, keeping the other 3 for future use, nothing like being prepared. Also shiny stainless steel in the shiny extension does look pretty
I have never had a bit come loose and no experience of wobble due to it being out of balance, unlike the CMT one.
Hope this helps.