Tightening the Hitachi M12V Collet Chuck - Anthony Leonard - How to do it

Oct 24, 2026

A practical, safety-first guide for owners of a Hitachi M12V router-trimmer with a loose collet chuck. The author describes how to unplug the tool, remove the base plate, springs, guides, shaft-lock components, then take out the brushes and bottom housing screws. After removing the armature assembly, the guide covers cleaning and applying an appropriate Loctite (preferably a specified green-type), tightening the collet and reassembling in reverse. Safety checks and notes on curing time and test startup are included.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages3

Reading Time8 min

AccessFree to download

Tightening the Hitachi M12V Collet Chuck

Preparation and Base Plate Removal

Brush and Bottom Housing Removal

Armature Handling, Loctite, and Reassembly

Tightening the Hitachi M12V Collet Chuck By Anthony Leonard My Hitachi M12V had a loose collet chuck. I couldn’t figure out how to tighten it as there was no shaft lock mechanism. So, I called Hitachi’s 1-800 line and got help from one of their technicians. I’m summarizing what he told me, and my experience to share with other M12V owners. This is meant as an aide, if you aren’t comfortable with this sort of operation, please find your closest authorized service center and let them do it for you. You can find owner’s manuals and service center locations online at the Hitachi site ([http://www.hitachi.com/hpt/wood/10routertrimmer/halp-ZZZ7GNOZ7CC.html](http://www.hitachi.com/hpt/wood/10routertrimmer/halp-ZZZ7GNOZ7CC.html)). I suggest that you familiarize yourself with the assembly before you take the router apart. The first thing to do is MAKE ABSOLUTELY SURE THE THING IS UNPLUGGED!!! My collet chuck was loose enough to remove just by spinning it by hand (which is why I did this whole thing in the first place!) Now, we need to remove the base plate from the shafts. This is done by first locking the plunge lock and then removing the nut(s) on the threaded rod that controls the plunge depth. Be careful, when you release the shaft lock with the nuts removed, the base will fly up pretty fast. Remove the base, springs, guides, the brass pill from the shaft lock, etc. You’ll probably notice that the shafts are dirty and make a mental note to clean them and wax them before you put them back together. Now we need to remove the brushes. There are two plastic caps on the sides of the body that are removed with a flat tipped screwdriver to release the brushes. I noticed that mine were loose and made a mental note to check them periodically. When you remove the cap, the brush assembly may jump out, so be ready. I suggest you make keep the orientation so you can put them back in the same way they came out. I noticed that both of mine had a corner knocked off (I wondered if that was the leading corner?) . Once the brushes are removed, you can now remove the four Phillips head screws that hold the bottom housing on. These are pretty tight, so make sure you use the proper size screwdriver to avoid stripping the screws. The technician said I might need two flat tipped screwdrivers to lever the casting, but mine came off without the need for prying. Be careful when you remove the assembly as the armature is coming out with it. (note that the \#37Stopper Piece may fall out – see it next to the top bearing?) Now you have the armature and the bottom cover (the cast metal part) out as a unit. The Hitachi technician suggested wrapping a cloth around the armature to protect it and chucking it into a vise. My vise has wooden cheeks that are pretty soft, so I didn’t bother with a towel – maybe I should have to be safe. Once it’s in the vice good and snug, I cleaned the threads on the collet and the armature shaft. The technician said to use green Loctite and tighten the collet chuck “good and snug.” I asked for a torque spec, but there was none. I looked at the 15 different types of Loctite at AutoZone and the red seemed most suitable. The green was for “after-assembly” and was a penetrating type. So, check out the Loctite (or other brand) and follow their instructions. They also specify to clean with some kind of special cleaner. One spec. on their chart was the thread diameter – I don’t know the number, but I think it is 10 or 12mm. I think the size of the flats on the collet is 23mm. What I did was use the 21mm wrench that came with the router and tightened the collet by using the wrench on the top piece of the collet. That may not be the best way todo it as you have to tighten the collet along with the chuck threads. But, I figured since it only needed to be “good and snug,” I wouldn’t be doing any harm (no more than when I install a bit) . Now, I’m chicken, so I turned the whole thing upright such that any excess Loctite would run awa

FAQs

What should you do before attempting to tighten the Hitachi M12V collet chuck?

Make absolutely sure the router is unplugged. The guide notes the base can fly up quickly when releasing the shaft lock.

How do you remove the brushes and bottom housing safely?

Use a flat-tipped screwdriver to remove the two side caps and be ready for the brush assembly to jump out. Then remove the four Phillips screws holding the bottom housing, using the proper screwdriver size to avoid stripping.

Which thread-locking agent does the guide recommend and how is it applied?

The technician suggested green Loctite and tightening the collet “good and snug.” The author applies Loctite after cleaning threads, follows the product instructions (including curing time), and reassembles in reverse.

Oct 24, 2026

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