Best Collets For A Round Column Mill Drill?

HBilly1022

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Waiting for my King PDM-30 mill to arrive and wonder what is the best collet system for round column mills. I have no experience with mills and only recently discovered there are different collet systems for the R8 taper in this mill drill. From info supplied on another thread, I understand one of the issues of the round column mill is that the X Y register is lost whenever the head is moved vertically. So I wonder if it is better to use an ER system than a drawbar collet. I envision the drawbar collet system requiring more vertical clearance to make changes from one size end mill to the next, since the whole collet has to be removed and they are much longer than ER collets. Can drill bits be used in ER collets?
 
Either collets will work. Yes you can hold drill bits in ER collets
 
Your mill has an R8 spindle taper. It holds R8 collets and other r8 tooling, nothing else. You can put an ER collet INTO your R8 collets, or get an ER collet chuck with an R8 arbor to fit your machine, but you cannot put a ER collet directly into your spindle. R8 collets work well, and are available inexpensively. They work. Downside is that they only hold tools and work that are within a few thousandths of the nominal collet size. So you can end up buying a bunch of collets. ER collets have a wider range of holding capacity. It takes fewer ER collets to cover a whole range of possible sizes. That said, most end mills and other tooling can be easily found to fit the most common nominal R8 collet sizes. The ER collet chuck will end up sticking out of your spindle, reducing the available space below for work, vises, rotary tables, and other things that eat up the headroom of your machine. The ER collet is shorter, but it is already hanging down further from your spindle. You can go either way or both, and both have advantages and disadvantages. It all depends on what you plan to do with your mill and how much you want to spend doing it.

There are several ways to regain your XY position after moving the head on round column mills.
 
I recently changed to the Tormach type tooling, which consists of one 3/4" R8 collet, and the tool holders all have 3/4" shanks about 1 1/2" long. I chose the ER20 collets, which will allow up to 1/2" end mills or drill bits. A set of 14 collets will cover all 29 drill bit sizes. A set of screw machine drill bits help to keep the length more consistent with other cutters and taps, etc, as they are 5/8th the length of jobber bits.

I modified my mill to allow quick tool changes with the push of the quill handle. See my post: Power drawbar for RF30 in the Enco,Jet,and Rong Fu forum.
 
I understand one of the issues of the round column mill is that the X Y register is lost whenever the head is moved vertically.


While true, one workaround is to move the X or Y axis to move the work from under the tool to make the tool change. Another way is to work with the quill out a bit so when all the way up you have clearance to change a tool.
 
I recently changed to the Tormach type tooling, which consists of one 3/4" R8 collet, and the tool holders all have 3/4" shanks about 1 1/2" long. I chose the ER20 collets, which will allow up to 1/2" end mills or drill bits. A set of 14 collets will cover all 29 drill bit sizes. A set of screw machine drill bits help to keep the length more consistent with other cutters and taps, etc, as they are 5/8th the length of jobber bits.

I modified my mill to allow quick tool changes with the push of the quill handle. See my post: Power drawbar for RF30 in the Enco,Jet,and Rong Fu forum.

Thanks Ben. I think may be confused about the proper terminology for collets.:confused 3: The ER collet system I looked at today had a collet chuck that is held in the spindle by the drawbar. The chuck stays in the spindle and small / short collets (I think that is what they are called) are inserted into the chuck. Each collet is only about 1 1/2" or 2" long and holds a specific sized tool. Here's a link to what I'm referring to; https://www.kmstools.com/magnum-15pc-collet-chuck-set-2954 The other system is a set of collets, each of which is held in place by the drawbar and each of which holds a specific sized tool. Here's a link https://www.kmstools.com/south-bend-12pc-collet-set-11133 The ER system only requires about 1 1/2" to 2" of clearance to change collets but the drawbar system requires about 4" to 5", so my thinking was that the ER system, which needs less room to swap, would be less likely to cause me to have to move the head. Does that make sense?

I never thought to look at the Rong Fu forum and thanks for that. As I understand it, the King PDM-30 is similar to the Rong Fu and probably the other machines in that thread and there should be a lot of very helpful info there. Looks like more reading tonight.

While true, one workaround is to move the X or Y axis to move the work from under the tool to make the tool change. Another way is to work with the quill out a bit so when all the way up you have clearance to change a tool.

Thanks Jim, I already thought about moving the project out of the way for tool changes but didn't think about keeping the quill out while working. I want to minimize the need for vertical head movements but I guess the only way to do that, is to know in advance what tools I will be using for a specific project. Since I've never used a mill and have no specific projects in mind, I can't really provide any useful input. So it looks like it's gonna be: jump in and swim.
 
My round column mill has an MT3 taper, the ER32 chuck I use now has reduced the need to hammer on the draw bar for me which I like a lot.

I havn't used the R8 but I believe they release more easily than morse taper.

I like the ER collets for their step less holding range.

you can load the ER collets at a bit of an angle or push the tool to far in then pull it back down to tighten when it's in the holder.

On my rf 25 type mill the top cover has to be opened to get at the draw bar which adds another issue if I've got the head up high (maybe I need to grow a bit :) ) .

Stuart
 
Well the decision turned out to be an easy one. When I picked up the mill today I also bought some tooling and mill supplies. The 20 piece end mill set I got only required 4 different sized collets and the end mills ranged from 3/16" to 3/4". So do I get the 15 piece ER 40 set for $250 or 4 drawbar collets for $32. That was an easy choice to make.
 
Well the decision turned out to be an easy one. When I picked up the mill today I also bought some tooling and mill supplies. The 20 piece end mill set I got only required 4 different sized collets and the end mills ranged from 3/16" to 3/4". So do I get the 15 piece ER 40 set for $250 or 4 drawbar collets for $32. That was an easy choice to make.

Nice, new toys :)

Also as a thought Er40 is toooo big. (Total personal opinion their)

I use an er32 chuck and the lock nut can be an issue if your using small end mills and hold downs, as the nut takes up some space.

Im thinking of getting a strait shanked er11(or is it 12) chuck to use for small stuff that i can hold in my er32.

On the cost side I think i paid about £20 for the er32 chuck and about £120 for a set of collets 2mm - 20mm

I recently got an er32 chuck for the lathe so I can double up on their usefulness :)

Stuart
 
So you got 4 R8 collets then. Not only were they less expensive than a set of ER collets but they are superior to the ER system in my books for holding end mills. I have a set of ER 32 collets for work holding but use a Sheldon holder or MT3 collet for tool holding.
 
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