Is it typical for endmills to work out of a chuck?

[slashmaster]

I was just trying to trim about a 1/16th off some steel. I was cranking just the X wheel and without even touching the Z wheel the endmill was slowly working it's way downwards. I'm guessing the endmill was working it's way out of the chuck. Is this common? What do I do about it? Feed slower? Or just try to tighten the chuck tighter?

[tool_man]

If I understand correctly,you are using a drill chuck to hold the end mill?If so,it doesn't matter how much you tighten the chuck.The end mill will work it's way out.You should be using the proper size collet.If your machine uses R-8 collets,you need to buy a set.They are not real expensive.

[cheetahcnc]

I have chucked up a mill in a drill chuck and plunge milled in a pinch, but any side load will usually pop the morris taper loose. Things get messy then...

Jim

[tobyaxis]

You can use the suggestion above or if you want to spend some $$ you can buy an Albrecht Diamond Chuck. It is Ideal for holding carbide tooling, but feeds and speeds will be much lower than a collet (suggested above and better than a drill chuck) and cutting forces will have to be reduced significantly.

You better off with a Collet or a Solid Tool Holder (ETM is Iscar).

http://www.albrechtchucks.com/tech_i...oated_jaws.cfm

http://www.use-enco.com/CGI/INPDFF?P...PARTPG=INLMK32

[slashmaster]

Originally Posted by tool_man If I understand correctly,you are using a drill chuck to hold the end mill?If so,it doesn't matter how much you tighten the chuck.The end mill will work it's way out.You should be using the proper size collet.If your machine uses R-8 collets,you need to buy a set.They are not real expensive.

I see, I was not aware this would happen. Would it work to drill and tap one of the holes that you put the chuck key into so you can put an allen screw in it to keep the endmills from going down?

[tobyaxis]

Originally Posted by slashmaster I see, I was not aware this would happen. Would it work to drill and tap one of the holes that you put the chuck key into so you can put an allen screw in it to keep the endmills from going down?

How will you centralize the tool? Besides that you might have a tough time drilling and tapping through the chuck. I have never done it myself, but I can imagine it is Hardened or Forged. Not very friendly.

[slashmaster]

Originally Posted by tobyaxis How will you centralize the tool? Besides that you might have a tough time drilling and tapping through the chuck. I have never done it myself, but I can imagine it is Hardened or Forged. Not very friendly.

It looks like as long as I don't use an allen screw too big I will have room so that I can use both, the jaws to hold it in center, and the allen screw to keep it from going down. But yeah it does look hardend. I was thinking about buying this collet from harbor freight so I won't have to wait but it doesn't seem to say what size it is http://www.harborfreight.com/cpi/cta...emnumber=46004 Does anyone know another store like that which might have them in stock so I don't have to wait?

[Crevice Reamer]

You are missing the point. You should NEVER use an endmill in a chuck. IT'S DANGEROUS!

Chucks are only held to the arbor by friction. Side force can loosen the arbor, sending it at YOU. Imagine a whirling sharp endmill ripping your skin.

Get yourself some Tormach quick change holders in 1/4, 3/8 and 1/2 and some same shank end mills. Or invest in a collet set.

http://littlemachineshop.com/product...itFast=tormach

CR.

[msomerville]

You need to be careful about buying tools from harbor freight. I guess even if the collet was not ground properly it would still be better than using a drill chuck.

Get some decent collets.

[One of Many]

As stated already. Get a set of decent R8 collets.

Cheap HF quality drill chucks will not keep the jaws parallel enough to grip an EM shank under side loading cutting steel. They are primarily for axial thrust cutting forces, not radial. For that matter cheap chucks barely hold a drill on center. If it isn't the jaws that fail to grip tip to tail, it will be the taper holding the chuck to the mounting shank that can losen. Either case, yes..it does get ugly when they come untogether at several hundred RPM.

I am no fan of the ER-like collet setup you linked to. The more connections you add to a spindle, the worse the runout and lower rigidity. Not to mention the HF quality again.

DC

[John Welden]

Originally Posted by slashmaster I see, I was not aware this would happen. Would it work to drill and tap one of the holes that you put the chuck key into so you can put an allen screw in it to keep the endmills from going down?

Trust the other comments and get some collets. You can plunge with a endmill in a drill chuck but thats about it. I guess if it was life or death you could do the set screw mod you're talking about. You could also glue your wheels on your car if you couldn't find any lug nuts. Maybe use coffee as motor oil since its the same color.

[One of Many]

Originally Posted by John Welden Trust the other comments and get some collets. You can plunge with a endmill in a drill chuck but thats about it. I guess if it was life or death you could do the set screw mod you're talking about. You could also glue your wheels on your car if you couldn't find any lug nuts. Maybe use coffee as motor oil since its the same color.

While drinking my morning motor oil and nearly spitting it all over the screen wrapping my mind around the contemplation after posting. The setscrew idea won't work at all. The jaw bores do not have a space between them to access what ever is being held. A good way to make a bad chuck even worse! Dho!

Ya still gotta admire inge-nub-ity and desire. We were there once too Slash. Learn and move on!

DC