milling tool holder question

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mikeamick
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Location: San Diego

milling tool holder question

Post by mikeamick » Fri Dec 02, 2011 3:53 pm

I want to start playing with my mill ... and need some advice as what tooling I need.

I'm thinking of getting a mt3 collet chuck .... then a couple of collects of popular sizes
like 7/16 1/2 9/16 .. I don't really have the money to buy a big set.

Oh and I see they are available in er23 er25 er32 er40 .. should I just go with the
er40 or what.

Then some endmills .. 2flute 4flute ..

I'm stopping by the metal store today and picking up so alum rod (to lathe) and some small blocks
to practice milling on.

I have a cheap vice to start with.

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SteveM
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Re: milling tool holder question

Post by SteveM » Fri Dec 02, 2011 4:14 pm

For end mills, you'll want end mill holders - they have a screw that holds them from pulling out. The spiral on an end mill can pull the cutter out and give you the wrong depth of cut. Don't ask how I know.

Note that the setscrew is for anything with a "Weldon" shank - that's a round shank with a flat. That's my you see flats on end mills. My fly cutters have them too.

Here's what one looks like:
Image
Get them with drawbar threads.

http://www.use-enco.com/CGI/INPDFF?PMPA ... PG=INLMK32

You can get a whole set in MT2 for $80:
http://www.tools4cheap.net/proddetail.php?prod=mt2em

MT3 may be harder to find, but I'm sure someone has them.

Not that the ER collet chuck won't come in handy. It may very well.

Steve

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mikeamick
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Re: milling tool holder question

Post by mikeamick » Fri Dec 02, 2011 7:23 pm

Thanks Steve .. will look for those. Just got back from the metal store and picked up
a good variety of metal to play with. pic included .. I know you don't use your drill
chuck for milling .. but .. I am afraid my butt is on fire .. so .. I'll load one of those
end mills up in the chuck and take some little nibbles just to see what happens.
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alum.jpg

Torch
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Re: milling tool holder question

Post by Torch » Fri Dec 02, 2011 10:36 pm

Stick to light cuts on the aluminium. I'd avoid the brass in particular as brass is known for "hogging" -- a tendency for the tool to dig in and pull. This can be a real big problem using the drill chuck. If you have the chuck firmly tightened on the end-mill, the mill may pull the chuck off the JT taper and now you have that nice spinning mass flying off in whatever direction it chooses. Don't Ask Me How I Know This(tm).

The same sort of thing can happen when taking heavier cuts on other materials too, just because of the vibration and side loading. When it happens in steel, you can kiss the end mill goodbye, even if the chuck doesn't launch itself off into space. Again, DAMHIKT.

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mikeamick
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Re: milling tool holder question

Post by mikeamick » Fri Dec 02, 2011 11:30 pm

Well .. the drill chuck came off its taper .. lol .. Not like you called it or anything .. grin

But I did get a little taste. Because of my lathe chuck .. I couldn't get the work very close
to the head stock (and under the mill) .. what is the normal thing to do, pull the lathe
chuck ? It just unscrews right ? How do you hold the main lathe turret still to do this ?

Oh .. and I got an alum and brass flat bar(?) because I don't have a gib/shim on the tale stock
and didn't know if it mattered what metal I used for it.

Torch
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Re: milling tool holder question

Post by Torch » Sat Dec 03, 2011 6:48 am

The gib is normally steel. The problem with using a soft material like aluminium or brass -- aside from the fact ductile materials can compress and deform in general -- is that soft materials can get hard materials like chips, dirt or grit embedded in them. At which point they act like sandpaper.

The lathe chuck may thread on some machines, but IIRC you have an HF 5980. On these machines the lathe spindle has a flange and the lathe chuck is bolted to that with 3 bolts that pass through the holes in the flange and thread into the chuck. The flange has a slight raised boss and the chuck has a slight recess so they are a tight fit to ensure concentricity. Once the bolts are loosened, give a tap around the circumference with a rubber mallet or dead blow. If you do it with the bolts still engaged, it won't drop on the lathe bed and damage things. A block of wood below the chuck is good insurance.

bedwards
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Re: milling tool holder question

Post by bedwards » Sat Dec 03, 2011 10:41 am

SteveM wrote:For end mills, you'll want end mill holders - they have a screw that holds them from pulling out. The spiral on an end mill can pull the cutter out and give you the wrong depth of cut. Don't ask how I know.

Note that the setscrew is for anything with a "Weldon" shank - that's a round shank with a flat. That's my you see flats on end mills. My fly cutters have them too.

Here's what one looks like:
Image
Get them with drawbar threads.

http://www.use-enco.com/CGI/INPDFF?PMPA ... PG=INLMK32

You can get a whole set in MT2 for $80:
http://www.tools4cheap.net/proddetail.php?prod=mt2em

MT3 may be harder to find, but I'm sure someone has them.

Not that the ER collet chuck won't come in handy. It may very well.

Steve
So...... the last milling project I did and had a depth problem, I was using just a R8 collet to hold the end mill and it kept moving. :oops: I feel stupid now. I have so much to learn.
thanks SteveM

be

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SteveM
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Re: milling tool holder question

Post by SteveM » Sat Dec 03, 2011 11:05 am

Just make sure that you get end mill holders with a threaded hole for a drawbar and not ones with a tang, otherwise it will pull the whole thing out instead of just the end mill holder.

I've been looking for B&S7 tooling and I've found end mills with B&S7 shanks, but with tangs. I can't see that these would ever hold, unless all you were doing with them was counterboring.

Steve

Harold_V
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Re: milling tool holder question

Post by Harold_V » Sat Dec 03, 2011 5:03 pm

bedwards wrote:So...... the last milling project I did and had a depth problem, I was using just a R8 collet to hold the end mill and it kept moving. :oops: I feel stupid now. I have so much to learn.
While it's difficult to diagnose what went wrong without having seen your setup, don't be quick to dismiss the use of collets for holding end mills. That's a perfectly acceptable method, and often yields benefits that are lost when using an end mill adapter (like the one shown). To be clear, I never used end mill adapters in all my years of machining (all on manual machines--no CNC involved) and had but one incident with an end mill pulling out.

An adapter can be to advantage, especially when clearance is a consideration, but they are not a mandatory accessory, and can be a poor investment for a guy with limited funds. You're far better served buying the few collets that are common shank sizes.

One of the negative aspects of using the adapter, in particular on flimsy machines, is the extension of the cutter beyond the bottom bearing of the machine. That's commonly the source of chatter and deflection.

Assuming the draw bar on your machine has a long engagement length with the collet (at least as long as the thread diameter), don't be afraid to tighten the drawbar. If you use a timid approach, you can expect the end mill to move, often out of the collet, a function of the helix angle of the end mill.

Harold
Wise people talk because they have something to say. Fools talk because they have to say something.

bedwards
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Location: Birmingham, Al

Re: milling tool holder question

Post by bedwards » Sat Dec 03, 2011 7:38 pm

Harold, I'm sure your right. I was timid in tightening the drawbar. I have since made me a dedicated wrench just for the drawbar (instead of a crescent wrench) and a deadblow hammer to tighten it. This was really the first project that I have used the R8 collets on. In the past, I have mainly used the machine for face milling.



Bryan

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