What's this thing for?

[Chunky]

I just bought a mill. It has a chuck just like a drill press. Do I need one of these things (see pic), and do I need one for every size end mill? Thanks

[mxtras]

That appears to be a Morse Taper Weldon style endmill holder.

The 'Weldon' part refers to the method of retaining the cutter in a precision bore with a set screw. It works fine but not all end mills have flats for the set screw(s) and this can be a problem if you plan to use solid carbide cutters unless you have a way to put a small flat on the shank of the tool.

The 'Morse Taper' part refers to the end that fits into the spindle of the machine.

You need a way to hold the cutters - yes. If you have a morse taper (MT2, MT1, etc) in your spindle, then this is one way to go. Hopefully, you don't have a morse taper in your spindle - they hold, but not that well and are a bad choice for milling in my opinion.

Do you know what taper the inside of your spindle is?

Personally, I would look into using collets if you can.

Scott

[ViperTX]

The drill chuck should be removeable....what sort of taper does the spindle have R8, Morse taper, etc. I tend to use 3/8 inch collets and get the end mills with that size fo shank.

[Chunky]

The drill chuck should be removeable....what sort of taper does the spindle have R8, Morse taper, etc. I tend to use 3/8 inch collets and get the end mills with that size fo shank.

I've learned that I have an MT2 spindle.

1) Why is that bad (per MXTRAS)?
2) Why don't you put the mills in the exiting drill chuck?
You can tell I know a lot about musheening.

[mxtras]

Chunky -

You may not know about mushrooming, but I really like the fact that you are not afraid to ask!

Morse Taper tools are held by nothing more than the taper. There is no drawbar to make sure the tool stays in the spindle. Morse Tapers are wonderful for drills but not for milling. All of the forces of drilling are acting to keep the tapered fit tight. But with milling, the forces are acting sideways, obviously, on the taper and it will loosen.

Additionally, morse tapers are more subject to failure due to trash. If you have built up crap in the spindle the tool can let go and fall out. On an R-8 spindle, the drawbar makes sure the tool (or at least the collet or arbor) stays put - you may have runout but at lest the tool won't hit the deck in the middle of a cut.

Mills in a drill chuck? Not recommended. The clamping area is not great enough nor is the accuracy. A tool that is running out will grab, chatter and fail quickly because a portion of the cutter is doing most of the cutting - the rest is going along for the ride. The overloaded portion of the cutter will dull quickly - there are a host of issues with tool runout. Can you run a cutter in a drill chuck? - yes. It's just not a good idea and I would not do it.

Any other questions?? Fire away, Chunky!!

.....why do you call yourself Chunky, anyway (if you don't mind my asking)?? How big 'a boy are 'ya?



Scott

[Chunky]

Originally Posted by mxtras .....why do you call yourself Chunky, anyway (if you don't mind my asking)?? How big 'a boy are 'ya? Scott

Friends finally convinced me that I was stupid to be using my real name online. When I was trying to think of a name some guy on the radio said he'd seen an old friend who'd gotten rather chunky over the years. I was in a hurry at the time so I went for it.

[mxtras]

LOL - Good answer, Chunky - good answer!

On your tool holder situation -

If you are stuck with the Morse Taper and have to use it for machining - here is my advice to you:

Keep all of your holders clean and well oiled - especially the Chinese ones as they seem to rust just by breathing on them. Keep an eye on them - pull everything out of storage every once in a while and make sure that the uncommonly used ones don't become neglected.

Keep the inside of your spindle spotless - clean it every time you unload a holder to prevent build up.

If you live in a humid region, keep you holders in a warm cabinet - a small light bulb in a cabinet works for me here in 'spit in the air to make it rain' Virginia - rust from condensation is a constant battle here.

Each time you load a holder, wipe it with a clean rag.

If you are milling for extended periods, you may want to remove the holder after the first few minutes of cutting - just to check the 'tightness' of the fit. If it comes out pretty easily, then you'll know to keep a close eye on it. If it comes out tight like it should, then you can go longer next time before you check it again. There are few things that will screw up you nice, new machine and tooling faster than having a holder come out of the spindle during cutting - especially at the faster spindle speeds.

If when you extract a holder you notice a black, sooty looking powder on the shank it is from the lack of correct taper fit. If all of your tools do this, then the taper in the spindle may be inaccurate and with import machines this is a possibility - not likely but it is a possibility. If the sooty looking stuff is noticed on only one or two holders then it may be the holder. Keep an eye on the ones that do this - avoid using them. You won't see the sooty looking stuff on drills - just milling holders. If the tapers do not match there will be movement between the holder and the spindle producing a fine metal powder. This is an indication of eventual failure (tool falling out of the spindle during use) so pay attention - you don't want a cheap holder to ruin your spindle bore (or your pretty new machine table, or vise, or your arm or leg!).

You may notice that the new holders don't hold as well as ones that are used - at least I have noticed this in the tailstock of my lathe when using less than premium tools. I may get flamed for this suggestion but I will put a light cross hatch pattern on the shank of new holders with Scotchbrite then mist them with light oil before stabbing them into the spindle. This improves the holding reliability. Some may think this is not a good idea but I have had holders that fit poorly and this method resolved the issue. Let the flaming commence.....

If I recall any other suggestinons, I pull post them up if you find these suggetions worthy.



Scott

[CNC Darren]

Originally Posted by mxtras Morse Taper tools are held by nothing more than the taper. There is no drawbar to make sure the tool stays in the spindle. Morse Tapers are wonderful for drills but not for milling. All of the forces of drilling are acting to keep the tapered fit tight. But with milling, the forces are acting sideways, obviously, on the taper and it will loosen.

Just as a side note, I use a 3 in 1 smithy that has a 3MT spindle in the mill head but it DOES use a drawbar to hold it in. The normal floor drill press my dad has also has a MT head but no drawbar. I'm guessing that it depends on the machine that its going in.

I'm still new to all this to but thats something I noticed.

Darren

[mxtras]

Standard MT tooling has no drawbar. Hopefully Chunky's mill does but I doubt it......?

Scott

[CNC Darren]

OK. the only endmill holder I have came with it so I wasnt sure. I'll have to remember that when looking for different size holders.

Darren

[Chunky]

I really appreciate all the time you guys are putting in to these responses. It really makes a difference to me and maybe others watching. I'm taking all this advice seriously and I'm glad I asked BEFORE I started ordering. I don't have a single mill for my mill. I started to order some from Harbor Freight but then realized I had no idea what I needed. I mean- I knew I needed some end mills. But I didn't know if they just went in the drill chuck that came with the mill or what. What I'm going to do now is go to the WEB and get some pictures of a draw bar. Then I can look at my mill and see if I have one. Sad ain't it.

[ViperTX]

The draw bar will go down the center of the spindle from the top...If you have one you'll see it at the top, in the center of the pulley/bearing mounted at the top end of the spindle. Usually end mills are held by a collet. For end mills you'll want some center cutting 2 and 4 flute ones...for your machine I would look at 1/8, 1/4, and 3/8 and with 3/8 inch shanks....that way you'll only need a 3/8" collet. Start with HSS end mills and then graduate to the coated ones...TiN, etc.