ER 40 collet vs. toolholder

[Craig_J]

Will an ER-40 collet hold a milling cutter as well as a solid toolholder with a setscrew? I am in the process of acquiring an RF-45 clone mill/drill with an R-8 spindle. I own a set of ER40 split collets that I use on my 10x22 lathe, and wonder if I should plan on acquiring a set of the solid toolholders. I have read that split collets will sometimes allow the tool to "climb" out, compromising the work. (I have seen this happen on a router.) But I have also heard that the ER-40 collets are superior to R-8 and C5 collets because they have more fingers. My mill will have 18" or so of vertical clearance, so I imagine I will normally have the 1-2" extra space for the R-8 -- ER40 chuck. I would appreciate some wisdom from the experienced machinists out there! Craig

 

[DMS]

This is one of those hotly contested debates (Tastes Great!, Less Filling!. VI! EMACS!, MAC!, PC!).

In general collets have better concentricity. This is especially important for small cutters (1/8" or less). For these cutters you want to go with a collet of some sort (either R8, or an ER collet of some sort in an R8 holder). For larger end mills you want units with a "weldon flat". This is a flat on the cutter shank for the set screw to engage. You won't find it on anything smaller than a 3/8" shank from what I have seen.

For what it's worth, I use R8 collets mostly, but have been switching to TTS collet holders (ER-20) recently. The nice thing about R8 holders and the TTS system is repeatability (in the Z), which is not a big deal on a manual machine, but on a CNC machine it is very useful.

It's mostly a personal preference. R8 collets tend to be the cheapest way to go to start.

Given you have a lathe, you could also turn up some holders.

 

[Swarfmaster]

Craig,

Just off hand, I believe that the set screw and flat will hold tighter than the collet. However, IMHO, the ER40 has enough clamping power for most all uses. I purchased ER40's for my small Grizzly Milling Machine and they work just fine. The tightning charts go way up for the larger size collets if you look up the stats.

Ray
Morgan Hill, CA

 

[OrangeAlpine]

I think this is an area will theory and reality collide. Yes, the holder will hold tighter, but is it a difference that you will see? ER's are way to popular with the pro's for it to be an issue. By the way, the R 8's are a minor PIA to use, especially to swap and you happen to be a shorty. The big downside of the ER's is they make the tool protrude further from the spindle. Is that an issue? Only you can answer that question. I started out with R 8's, switched over to DA 180's. Yes, they protrude more, but life is SO much sweeter!

Bill

 

[Syaminab]

All my toolholders, for precision are ER32, on CAT 40 and HSK63 holders, I only have a weldon, because the Tap holder with floating head needs in in the cnc. I Highly recommend ER systems because of versatility, the eppinger holders in thr live tooling lathe uses them too. So I standardized all the machines with TIR under .0002. If it helps I chose REGOFIX, swiss collets, both through spindle coolant and sealed.

 

[darkzero]

I recently got a RF-45 clone but I haven't used my ER40s hard enough to give any feedback. But you can use a Lyndex bearing nut or Rego Fix friction bearing nut that allows higher clamping forces.


These are the Lyndex

 

[DaveSohlstrom]

I started out with R8 collets on my mills. Switched to Tormack TTS and haven't looked back, love them. Spendy yes but Z repeatability is worth it.

Dave

 

[kd4gij]

ER40 will be just fine for the mill you are looking at.

 

[jfcayron]

This is one of those hotly contested debates (Tastes Great!, Less Filling!. VI! EMACS!, MAC!, PC!).
In general collets have better concentricity. [...] For larger end mills you want units with a "weldon flat". [...] You won't find it on anything smaller than a 3/8" shank from what I have seen.

I have been using a 3/8" R8 collet with satisfaction until recently when I bought a holder from Enco.
I have not tested it for concentricity (looks OK) but the fit is tight (it goes "pop" when you remove the tool).
What matters to me is the Z repeatability and the assurance that the mill will not slip even if I do not tighten the collet like a madman.
also, I find it easier to change tools with the holder, provided they have the same shank size.

BTW Enco has a 3/16" size.