YAKAMOZNew Design 1/2 Inch Shank Router Collet Extension Chuck Converter Adapter, Extends The Router Bit an Additional 2-1/4", Convert 1/2-Inch & 1/4-Inch Shank Bits

Had to correct (rewrite) my review of this item due to my error.This collet is well built and I checked to make sure the extension doesn't have excessive runout. I found it to run true with no vibration. I primarily will be using this with the 1/2" insert.

Very nice extension collet, seems well made and worked well in my plunge router. Only one complaint - they should include the necessary spanner wrench with the purchase. I’m a tool junkie, but I didn’t have a spanner for this! Minor inconvenience but it would be worth it to me if I had the option to buy it with wrench included for another $5 - $10.

Used on my slab flattening set up. No vibration and works great

Purchased this for a specific task involving a deep router job. This extension did just that extended the reach of the router bit. Excellent quality extension which did not bend during use allowing router options to router right to the point needed. Highly recommend this extension if an extension is what you need.

I was really hoping this would work for me, but with my router the vibrations ended up being way too great. I have a cheap router, so I am not sure if it was the collet extension or my router that caused the problem. The collet looks to have all the right features, it just didn't work in my case. I ended up just buying a router bit with a longer shaft for the project I was working on.

Its a nice product but you can not use it with out the spanner wrench that is sold separatelybut not offered with the unit or even mentioned when you are about to submit an order for one.Suggestion: Sell it with the spanner wrench.

I purchased the collet extension adapter for the same reason as everyone else; limited range of router position to accomplish much reach past the deck of the router table.In principal, I like the concept of the Yakamoz adapter; interchangeable collets with a single mandrel that can remain in the router while quick changing collets (these collets are from the ER system used in the machining world, this form factor being ER20).The mandrel (alone) appears to be machined with decent quality and, when mounted into the router, holds centering to an acceptable level (total indicated runout as low as 0.002" can be achieved if you fuss with it a bit), and runs at router speed with fairly minimal imbalance.The problem comes when a collet & cutting bit are chucked up for use; runout (as measured on the ground smooth cutter shank) degrades to 0.005" and worse and, when run at router speed, produces excessive vibration. In my view, it PRESENTS A LIKELINESS FOR DAMAGE TO THE ROUTER AND PUTS THE OPERATOR INTO HARM'S WAY. I tried fussing with the setup quite a bit, and went through all this again with a second kit, all without success.I believe that the real problem lies with the ER20 collets supplied and, with better collets, the system could be a winner. I looked into buying better collets from a machinery supply house, and it can be done, but the final cost to get there is just not justifiable.I returned these kits to Amazon and tried one of these...https://www.amazon.com/gp/product/B00IG6YGBE/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1… also known as ASIN B00IG6YGBE.This extension adapter does much,much better and will be the one I keep. This model only accepts cutters with ¼" shank, and in the future I may have to buy a separate model to accept 1/2" shanks, but for now I have a solution that works with the majority of my cutters.

Very difficult to tighten, threads are fragile and easily damaged. Wrenches don't stay on well, slip constantly when tightening or loosening router bits.Has to abandon using it.