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Correct way to hold end mill?

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Rcdizy

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#1

Rcdizy

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#2
Is the proper way to hold an end mill to use a collet?

Is it ok it the collet set is metric, to hold inch size tool shanks?

What is the cheapest DRO option for a little machine like this?

https://www.ebay.com/sch/i.html?_fosrp=1&_from=R40&_sofindtype=0&_nkw=MT3+collet&_in_kw=1&_ex_kw=&_sacat=0&_udlo=&_udhi=&_ftrt=901&_ftrv=1&_sabdlo=&_sabdhi=&_samilow=&_samihi=&_sargn=-1&saslc=1&_fsradio2=&LH_LocatedIn=1&_salic=2&LH_SubLocation=1&_sop=12&_dmd=1&_ipg=200

I would prefer to locate what I need out of Canada if possible.

Any suggestions?





 

ttabbal

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#3
The collet doesn't know what you're putting in there. So if you use an inch tool in a metric collet it's not going to freak out. The trick is to ensure that tool is within the clamping range of the collet you are using. It's pretty easy in ER style collets, as they have a wide range. A little harder in R8 as they have a small range, then you add measurement system differences.

In fact, with ER collets, I've read it's actually a little nicer to get metric as they are usually 1mm range with 1mm spacing, no gaps.
 

markba633csi

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#4
"In fact, with ER collets, I've read it's actually a little nicer to get metric as they are usually 1mm range with 1mm spacing, no gaps."
Good to know
Mark
 

Dave Paine

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#5
Cheap, DRO and sourced in Canada are a difficult combination.

A Canadian source of DRO's is Shooting Star Technologies. I have their original CBX on my mill. Bare bones functionality but it works. The cost has gone up a lot, likely more than your mill.

Star technology

An HM thread on adding DRO's to a mini mill similar to your machine. One of a number of threads.

HM thread on adding DRO to mini-mill

Another example.

Another HM thread on adding DRO to mill
 

Aaron_W

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I think the right answer is an endmill holder, but good collets work too. I use an ER32 collet chuck for my endmills.

The concern is having too much run out with a drill chuck / cheap collets which will damage your endmills.


I don't know your machine, but it looks like one of the common Sieg built mini mills sold by many vendors. You might look at Little Machine Shop for the DRO, they offer packages for many of these small mills.

https://littlemachineshop.com/products/product_category.php?category=-1536942993
 

9t8z28

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#7
Yes the proper way to hold an end mill is with a collet. You could use end mill holders that have a set screw that clamps on the weldon shank but on your machine it will take up a lot of your Z travel. Is your machine made for R8 collets or MT2 ? I would use metric collets for metric tooling and inch collets for inch tooling. You could use ER collets but then you would need an ER to R8 or ER to MT2 adapter which takes up Z travel again.
R8 collets do not work well unless the tooling is within a few thousandths of the intended size.

The best DRO system are the iGaging DRO’S. You can use them as is or get a Blu-Dro and tablet and have almost a full functioning DRO display and functions.
 

Rcdizy

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#8
Yes the proper way to hold an end mill is with a collet. You could use end mill holders that have a set screw that clamps on the weldon shank but on your machine it will take up a lot of your Z travel. Is your machine made for R8 collets or MT2 ? I would use metric collets for metric tooling and inch collets for inch tooling. You could use ER collets but then you would need an ER to R8 or ER to MT2 adapter which takes up Z travel again.
R8 collets do not work well unless the tooling is within a few thousandths of the intended size.

The best DRO system are the iGaging DRO’S. You can use them as is or get a Blu-Dro and tablet and have almost a full functioning DRO display and functions.
MT3 I believe
 

Ken from ontario

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homebrewed

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I put 3 iGaging remote-reading DROs on my mini mill. The remote readout feature is nice because it gives you more options on how to install the scale and sensor on your mill. These can be found on a number of online retailers. You don't get all the nice features a true DRO system offers, but if you really want all the bells & whistles you can interface the things to a tablet via the TouchDRO system or similar. Google Yuriy's Toys for more info on his system. I haven't gone that far but many sing its praises.
 

shooter123456

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#12
I think the right answer is an endmill holder, but good collets work too. I use an ER32 collet chuck for my endmills.

The concern is having too much run out with a drill chuck / cheap collets which will damage your endmills.


I don't know your machine, but it looks like one of the common Sieg built mini mills sold by many vendors. You might look at Little Machine Shop for the DRO, they offer packages for many of these small mills.

https://littlemachineshop.com/products/product_category.php?category=-1536942993
The concern with holding an end mill in a drill chuck is actually one of safety, unrelated to run out. The drill chuck is held onto the arbor by a jacobs taper, which means there is no positive retention to prevent pull out (Like a drawbar holding a collet). It is designed to handle forces straight up into the spindle when drilling. When milling, there will be sideways force and downward pulling force. If the drill chuck is pulled out of the taper, it is now a spinning projectile with a sharp tool in it which is obviously dangerous for the user, as well as potentially damaging the workpiece, the machine, or other things nearby.

Collets are the way to go. I can't tell if you have the R8 or MT3 spindle, but the matching collet will hold the tool just fine. I had no issues with R8 collets on my mini mill, even when I had it CNCd and running a 1.5 HP treadmill motor. Just keep an eye on runout for the smaller tools as too much can cause them to break.
 

Aaron_W

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The concern with holding an end mill in a drill chuck is actually one of safety, unrelated to run out. The drill chuck is held onto the arbor by a jacobs taper, which means there is no positive retention to prevent pull out (Like a drawbar holding a collet).
I think you are talking about using an endmill in a drill press. The drill chuck for my mill is threaded onto an MT arbor and held in place with a draw bar. I think an arbor and draw bar is a common method for holding drill chucks in a mill.
 

shooter123456

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I think you are talking about using an endmill in a drill press. The drill chuck for my mill is threaded onto an MT arbor and held in place with a draw bar. I think an arbor and draw bar is a common method for holding drill chucks in a mill.
Ahh, I see. No, I was specifically referring to using the drill chuck in a milling machine with an end mill. The one that came with my mill, and all the drill chucks I have ever bought, are just chucks with a jacobs taper, pressed on an arbor like this one: https://www.mscdirect.com/product/details/92302413

Up until now, I did not know they made threaded drill chucks.
 

GrayTech

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#15
For Shure with that type of mount you can use your drill chuck to hold tools if runout is good enough, but a arbor with an ER32 collet chuck will reduce tool and chuck stick-out/flex, and increase your z axis capability.

Metric ER collects didn't work well for me on most inch size tools, especially a problem with fly cutters and face mills etc. I think they just lack good contact, my inch collects are a press fit on inch tools with low runout and work very well. I think the inch collects are the way to go for inch tool. You can find them on eBay for around $60 for arbour and collet set together.

Sent from my H3123 using Tapatalk
 

P. Waller

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#16
Yes the proper way to hold an end mill is with a collet.
The "proper" way to hold an endmill is the way that the machine spindle allows, many machines will not hold a collet in the spindle directly. Therefore a collet tool holder, setscrew tool holder or shrink fit holder is required.

The advantage of holding a tool in a tool holder in a collet spindle machine it that the Z axis zero remains relatively constant if the tool is removed and returned to the spindle. A collet spindle will not repeat nearly as well in Z as a Cat, BT or MTB spindle. If you do not do many tool changes then by all means hold them in a collet.
 

wa5cab

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#17
In fact, with ER collets, I've read it's actually a little nicer to get metric as they are usually 1mm range with 1mm spacing, no gaps.
With Inch marked ER collets, it depends upon which set you buy. Most manufacturers seem to make their sets two ways. And then some of them offer sets in 1/16" increments (fewer collets) which don't or won't cover the contiguous range from the smallest nominal diameter to the largest.

The inch size marked sets are easier to use if you are using inch size milling cutter shanks because they are direct reading. If you want to use a 1/8" shank cutter, you use the collet marked 1/8".
 

38super

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#18
Fully engage the end mill shank in the collet, ensure collet nut is tight. Have had end mills try to walk out when I needed stick out.
 

ttabbal

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#19
Look up the torque spec for whatever collets you use. They want to be surprisingly tight. ER40 is around 100ft/lbs. The only time I've had something slip was when I didn't tighten it properly.
 

wa5cab

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#20
I'll add that it also depends upon how much trouble it is to remove the drill chuck and install the collet or collet holder. I can't tell from the photos how the drill chuck is attached to the spindle. But in general, milling cutter shanks are harder than drill bit straight shanks. The drill chuck jaws are normally hardened, so make a poor way to hold a hardened cutter shank. Unless you very seldom need to hold a hardened cutter, you should use some sort of collet, all of which have the advantage over the drill chuck of having much more surface area in contact with the cutter shank.
 

Aaron_W

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Ahh, I see. No, I was specifically referring to using the drill chuck in a milling machine with an end mill. The one that came with my mill, and all the drill chucks I have ever bought, are just chucks with a jacobs taper, pressed on an arbor like this one: https://www.mscdirect.com/product/details/92302413

Up until now, I did not know they made threaded drill chucks.

I am the opposite, the only place I've run into Jacobs tapers is on a drill press. Granted I'm not well traveled in the machinery world, and mine are threaded. Hand drills typically use threaded chucks these days.

I had to replace a drill chuck recently on my drill press (lost in a move) and it was harder than I expected to find the right Jacobs taper on a chuck. Found quite a few threaded chucks and those with various taper shanks attached for machining use.

Until now I've never had reason to question how those shanks are connected to the chuck, just assumed they were permanently attached. It is quite possible you are correct and they use a Jacobs taper between the shank and the chuck.
 

wa5cab

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#22
I think that there is a 60's vintage Jacobs catalog in Downloads. If not, I'll add it after dinner. But drill presses and small mills come with all sorts of spindle noses. That's one of the first questions that you ask before buying one.
 

Chipper5783

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#23
What are you doing with your machine? What sort of projects are you working on? The answer will influence what tooling you would consider. As others have stated - if your Z-axis realestate is important, then a direct mount MT3-end mill will give you the most room. Of course, your vise is taking up a good bit of "Z" room, so maybe the space is not an issue?

Of course, if you are working tougher materials (looks like a plastic type material was your most recent job) - then you may want to pull everything in as much as possible to stiffen your set up - but if that is not where you are headed, then maybe it does not matter?

Yes, collets give you a range of clamping capability, but do you really need that range? If you go with an ER collet system, then you'll need a chuck and that consumes a bit of head room. Of course it is a small mill, so you could get away with about an ER16, and that would not consume too much room.

The Weldon style end mill adapters hold very positively, and in small sizes do not consume much of that valuable "Z" realestate. The adapters are quite stiff (sturdy) and pretty cheap (less complex than a collet chuck and set of collets). If you use end mill adapters, you could standardize on just 2 or 3 sizes of end mill shanks. You have a small mill, stick to smaller end mills. Often the small end mills come on some sort of a standard size shank (i.e. 1/8" end mills are available on 3/8" shanks).

Stay in the game a while and you'll have all of the above for holding end mills!

The cheapest DRO? None at all. Glue a flat tape measure (thin metal rule) to the table and count turns. DROs are great, but much very good work has been done without one. I have 2 mills, both are well equiped and nice to use. The smaller one has a DRO, the larger one (Cinci's smallest mill) has the ruler glued on - the larger one gets used the most. Which mill really depends on the job to do.
 

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