Bit wont tighten down in collet - Hitachi M12V2 3Router

This photo is from a Dremel (not Drill Master) but it should be similar. Your tool may have different size collets that take different size diameter shaft bits. You may have the wrong collet (collar) for the bit you want to use.
If your tool only has one size collet then there could be debris stuck in the collet slits which prevent the collet from compressing down on the shaft bit when the top nut is tightened. And sometimes it just takes more torque on the nut that screws over the collet to really tighten it down on the shaft

Inserting the bit should be the same on all versions of the Makita 3612 router. It does depend on the bit size. Press the shaft lock to keep the shaft from turning. I think the lock is close to the handle on one side of the router when you hold the router with the bit/collet up. For small shaft bits, insert the appropriate collet sleeve into the collet cone. Then insert the bit completely into the sleeve. For larger shaft bits, insert the bit completely into the cone. Use the wrench to tighten the collet nut securely. Unlock the shaft lock. Do not over-tighten or leave the bit loose in the collet cone/sleeve. Over-tightening can break the collet cone. Leaving it loose can result in the bit flying out of the collet cone. Either way, injuries can occur. To remove a bit, loosen the collet nut and then remove the bit (or bit and collet sleeve).

The manual is available on the product page: https://www.makitatools.com/products/details/3612 . The direct link to the manual is https://cdn.makitatools.com/apps/cms/doc/prod/361/df12a409-2bd0-48c3-aa38-d635a480a76e_3612_IM.pdf . See page 8.

I hope this helps.

Cindy Wells

In your kit, you will find some collets to hold the smaller bits. Unscrew the cap, insert the collet and replace the cap. Inset the smaller bit and tighten the cap. The collets have slots cut into them so they can tighten down on the bit.

it is easy, you may find first time that it will not be so, but if you follow advice, it will become even more easy.

1. switch off motor
2. unplug from power
3. find button on the base close to rotating bit, press and hold, this is shaft lock which if applied correctly (you may need to rotate shaft a bit till it fully engage) will stop shaft from rotating
4. apply small spanner (provided with set) to collet collar (collet have two indentations fitting perfectly little spanner)
5. if shaft is held up, turn spanner anticlockwise, then use your hand to undo collar completely
6. remove collet and bit - separate bit from collet
7. collet comes in many sizes, select correct size for new bit
8. insert collet into throat
9. lightly screw in collar
10, insert new bit, at least 2/3 of the bit shank must be inserted into the collet!
11. held shaft lock button pressed
12 hand tighten the collar till bit is locked firmly in place
13. do not use spanner to tighten! if collar do not held properly, re-tighten by hand only!
14. wear always glasses when operating dremmel, or any other rotating machinery, it is not a toy! and exploding bit will penetrate not only your bit of woo, or metal but your eye as well... and your have only two and no spares...

if you find my advice useful, please do not hesitate to vote4 for me, or leave comment, or both... thanx!

User Error! There are different diameter collets. I bet you are using a larger diameter bore collet than the bit outside diameter. Collet can be purchased at any hardware store. To remove unscrew nut, remove collet and replace with proper diameter.

the collet is either the wrong size for the shaft on the attachment or is missing alltogether

could be a couple things. First how is the shank on the bit e.g. is it worn down, second is it the right size for the collet being used (have to ask) and what is the condition of the collet and collet nut. What I would do is make sure there is nothing to prevent from completely tightening the collet nut. Also make sure if the collet locks into the nut that it is properly installed. Lastly make sure that you use the wrenches provided to tighten the assembly. If this doesn't help please provide the model number and brand and I will do some more research.

Any time I have ever come across this problem over the years the cause of it is a damaged collet due to overtightening. The solution is to replace the cone shaped piece ( the collet ) and take care not to overtighten in the future.

Changing Bits: 1. Unplug the tool. 2. Turn the knobs on either side of the tool to loosen the base. 3. Remove the base. 4. Press the spindle guide to lock down the shaft. 5. Use a wrench to loosen the collet. 6. Remove the bit and collet. You may have to tap on the collet to loosen; careful not to tap on the cutting edges of the bit. 7. Insert the new bit and collet. 8. Use a wrench to tighten the collet into place. 9. Replace the base.

Depends on the head you have on the tool. If it takes collets, you need to match the collet size to the shaft on the bit. There are I believe 4 different collet sizes.

You have the threaded shaft which is hollow and connected to the tool. then you put the proper sized collet inside that shaft and half of it will stick out. This is what actually holds the bit. Next, you put the 'nut' on the shaft, but don't tighten it yet. Put the bit into the hole in the nut as far as it willl go, then back it out about 1/8 inch. Now you can tighten the nut by holding down the button on the front of the tool until the nut does't turn any more. You can buy a 'nut' that works with any bit, no collets used, for about $10. Home depot, Lowes etc or online.

If you're not sure what I'm talking about, you can probably find pics of collets etc. by going to google images.
It would probably pay to contact Dremel or look online for the manual also.