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Collets for Mill/Drill

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Investigator

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#1
Hope you Grizzly folks don't mind my posting here, since there is lots more traffic.......I have one of the RF30 clones (I think Enco) very similar to the Grizzly G3358, or the G1006.

My question is about what tool holding to use. The Mill/Drill has an R8 spindle. I know I can use R8 collets for holding both end mills and drills, but that the shanks have to be the exact size of the collet. Taking into consideration the tram issues if the head is raised or lowered, as well as the tool shank sizing on the R8 collets, I am wondering about getting an R8/ER32 collet adapter to use. My thought is that using the ER32 collets gives me a bit more of a range of shank sizes to use if I needed to get an odd drill here or there. The ER32 collets and adapter would also offer a similar protrusion from the spindle if I needed to change to a drill chuck or an endmill holder. My thinking is that this would help remove the need to raise the head of the mill while working on a part, and avoid the re-tramming issues with round column mills.

Am I close to being correct? What thoughts or suggestions are there on this? What other considerations and options have I overlooked?
 

mikey

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#2
I have an RF-31 so I'll give this a shot.

Yes, an ER-32 chuck is a good option vs R8 collets, for the reasons you mentioned. One system you might look at is the Tormach TTS system. Their system uses a 3/4" R8 collet with a flat ground nose to hold their tools but many tools will fit into it. Their ER-32 chuck is under $40.00 and is totally adequate. The good thing about the TTS system is that you only need to loosen the drawbar and exchange tools instead of exchanging R8 collets - very fast to use.

An ER-32 system will hold anything from 1/16" OD up to 3/4", is very accurate with good collets and a good nut, and takes up about the same head space as a drill chuck. You would need a large collection of R8 collets to accommodate all the tool sizes an ER set will accommodate. Like all systems, cheap collets are not worth their cost so if you go with an ER chuck, buy decent collets. Techiks, Crawford, ETM, Rego-Fix and Lyndex are some good ones. I would avoid Chinese collets unless you are strapped for cash; runout can be an issue with these. Buy a good nut - I like ETM and Rego-Fix nuts.
 

Splat

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#3
I've had endmills slip in collets so I use endmill holders now. For drill bits I would go with an R8/J3 arbor for this Accupro drill chuck, which I now have and love.
 

FanMan

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#4
I use an Albrecht keyless chuck on an R8 spindle when I need to use a drill that I don't have a collet for.

Everybody talks about the hassle of a round column mill, but if you raise or lower the head all you have to do is throw in an edge finder and reset the x, the y won't change if the head's reasonably in the same place.
 

Investigator

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#5
I'm probably missing something, but I dont see the advantage of the TTS system. It looks to me like its an ER collet holder with a shaft being held in an R8 collet, instead of an ER collet holder with an integral R8 shank. What have I missed?
 

mikey

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#6
Nothing you missed. It is much faster to loosen the drawbar, remove the chuck and replace it with another tool. With an integral R8 holder, you have to loosen the drawbar, knock the R8 arbor loose, then totally unscrew the drawbar and then screw the drawbar in to tighten the next tool. The TTS system takes seconds to swap tools and they are held securely and with precision. You can certainly live without the TTS system; I just prefer it.
 

darkzero

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#7
To add to what Mike said about the TTS system, the shank on them is much shorter than an R8. So chances are there may be many more times where you can make a tool change without havingto move your table to the side or lower your knee or raise the head to get the tool out.

This happens to me a lot. I just live with it & luckily I have a DRO which makes it quicker but everytime it happens to me I think about the TTS. Just not having to fully unscrew the drawbar to change a tool alone is worth it IMO.

Unfortunately it will be too costly for me to swap over to the TTS system, well more than I want to spend but who knows, I still might make the change one day.
 

coffmajt

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#8
I use endmill holders for the same reasons posted above, collets can slip with heavy cuts. For drill bits I just use a drill chuck on an R8 == Jack
 

Buffalo20

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#9
I never liked end mill holders, I use a lot of carbide end mills and the vast majority of the HSS end mill, do not have the Weldon pocket. I'm not about to start grinding a flat in a new end mill. With R8 collets, Din 6388 collets and ER32/40 collets, I've never had an end mill move. Maybe I'm lucky or the fact I make sure the collet and the endmills are clean and dry, before use.

What work for one, may or may not work for others.
 

Investigator

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#10
Nothing you missed. It is much faster to loosen the drawbar, remove the chuck and replace it with another tool. With an integral R8 holder, you have to loosen the drawbar, knock the R8 arbor loose, then totally unscrew the drawbar and then screw the drawbar in to tighten the next tool. The TTS system takes seconds to swap tools and they are held securely and with precision. You can certainly live without the TTS system; I just prefer it.
Got it, I understand the possible advantage now, thanks for the explanation.
 

Silverbullet

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#11
Let's add another for er32 , you don't have to reach up top to change the collets or tooling . I say that because from a wheelchair ITS easier.
 

RJSakowski

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#12
One final advantage of the TTS system is that there is a precisely reproducible z axis reference. For a properly prepared spindle face (see Tormach white paper), Tightening the R8 collet draws the shoulder of the TTS tool holder tight to the spindle face for excellent repeatability. In contrast, an R8 collet will draw the tool in as the collet is tightened. The tool will have to be re-referenced each time it is installed. Even an R8 end mill holder will change the z axis position slightly with tightening which is why sme shops use a torque wrench to tighten.

For me, this is the biggest advantage as it permits me to load up tools and pre-reference them. I use the Tormach surface plate and digital height gage to externally set up all my tool offsets. I have digital dial indicator which is mounted in a TTS holder and I make one reference measurement when I set up my work. That measurement is used to calibrate the height gage. If I need to replace a tool, I install the new tool, set the offset with the height gage and I'm good to go.
 

external power

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#13
This thread is just what I needed to see, as a new guy who has had a endmill slip while cutting.
Thanks for letting me join..Doug
 

mikey

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#14
Experiences vary and anything that can happen, probably will happen. I've had end mill holders slip enough that I avoid them in preference to an ER chuck that has never slipped. A collet will also grab concentrically, while an end mill holder will always be a tiny bit off center by the amount of clearance in the holder. For most jobs, this is not an issue but when you need accuracy (like cutting key slots) then it does matter.
 

RandyM

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#15
Experiences vary and anything that can happen, probably will happen. I've had end mill holders slip enough that I avoid them in preference to an ER chuck that has never slipped. A collet will also grab concentrically, while an end mill holder will always be a tiny bit off center by the amount of clearance in the holder. For most jobs, this is not an issue but when you need accuracy (like cutting key slots) then it does matter.
I have often wondered about this. Thanks Mikey.
 
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