[slcoleman]

I have a MicroMark benchtop milling machine which came with a tapered shaft/chuck assembly for holding the endmill, and it seems as soon as the bit touches the workpeice the chuck falls of and damages the project. It doesn't matter how hard I try to seat the chuck on the taper. For drilling holes this would work fine, but using it with an endmill seems to be a lost cause. Is there a special trick to properly seating the chuck, or is this setup a waste of time for milling?

I have been unable to use the mill for any meaningful projects thus far. I'm thinking that I need to replace the tapered shaft assembly with something that has a chuck directly attached to the shaft, but have not found where such a part if one is available and have not had the luxury of the time to design and make one as I only (attempt to) use it for occasionally. Other than trying to braze the chuck onto the shaft I don't see how this setup can possibly work for milling. Are there any after market replacement parts for this problem? Any Ideas?

[M250cnc]

The simple answer is, the chuck you are using is a drill chuck. It is not designed for side loads only drilling.

You need to use collets directly in the spindle or get a milling chuck and a set of collets.

What you are finding is that the cost of the mill is just the beginning of spending loads of money.

[rowbare]

Are you using a drill chuck for milling? That is a no-no. Drill chucks and the tapers that hold them aren't meant to handle side loads. Use collets or endmill holders.

Endmill holders and collets are threaded for a drawbar. The drawbar keeps the holder/collet firmly against the taper.

I am assuming that your mill is and MT3 taper. You need something like this: LittleMachineShop.com - End Mill Holder Set, 5-Piece 3MT - 3/8-16

or
LittleMachineShop.com - Collet & Chuck Set, 3MT, ER-32

or simple MT3 collets like this: LittleMachineShop.com - Collet, 1/4" 3MT

plus of course a drawbar.

Good luck!

bob

[slcoleman]

Thanks Bob!

I knew I was missing some equipment but didn't know where to go look for it. Its been more than 30 years since I touched a mill, and had not thought of looking for collets to fit the machine. The only time I used a collet in the past was with a lathe.

[pp7]

I have a MicroMark benchtop milling machine which came with a tapered shaft/chuck assembly for holding the endmill, and it seems as soon as the bit touches the workpeice the chuck falls of and damages the project. It doesn't matter how hard I try to seat the chuck on the taper. For drilling holes this would work fine, but using it with an endmill seems to be a lost cause. Is there a special trick to properly seating the chuck, or is this setup a waste of time for milling?

I have been unable to use the mill for any meaningful projects thus far. I'm thinking that I need to replace the tapered shaft assembly with something that has a chuck directly attached to the shaft, but have not found where such a part if one is available and have not had the luxury of the time to design and make one as I only (attempt to) use it for occasionally. Other than trying to braze the chuck onto the shaft I don't see how this setup can possibly work for milling. Are there any after market replacement parts for this problem? Any Ideas?

I don't have any room to make fun of anyone for this. I started learning to mill 2 weeks ago when I got my zx45 and I did the same thing. I tried to mill using a drill chuck but it kept falling out. I ended up ordering one of these end mill holder sets on ebay: end mill holder set items - Get great deals on Business Industrial items on eBay.com!

They seem to work fairly well.

[spuddevans]

I have a MicroMark benchtop milling machine which came with a tapered shaft/chuck assembly for holding the endmill, and it seems as soon as the bit touches the workpeice the chuck falls of and damages the project. It doesn't matter how hard I try to seat the chuck on the taper.

I could be wrong here ( it has happened to me once or twice before ) but it sounds like you are missing a drawbar to tighten and hold the chuck or collet in the spindle.

You can make your own drawbar with a short length of threaded bar that matches the thread on the thin end of you chuck, you just need enough to stick up a little above the top of the spindle ( remove any removable cap on the top of the spindle ), then cap it with a good sized washer and then finally a nut to tighten the whole arrangement. ( you dont have to tighten it by much, otherwise you will be hammering on it to release when you want to change chucks/collets )


Tim