R8 collet vs ER?

autogateman

Rod Braud
Joined
Jan 6, 2017
Messages
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Are there any advantages to ER collets for my mill vs sticking with R8? I’m considering getting an air power drawbar because I’m 5’7” and can barely reach my drawbar lol. But if I get ER, then I only have to reach up to the spindle brake lever. I know this seems elementary, but it really is a pain ha

Thanks guys
Rod
 
The only real difference you'll deal with is that the ER holder eats up some height compared to R8 right in the spindle. They're not terribly useful on an R8 mill and are mostly used as discrete tool holders on CAT taper mills because they hold constant tool lengths.

I use an impact on my draw bar. Don't even need to engage the brake to change tools but I understand the dilemma of reaching. But you'll still end up changing from the drawbar to put your drill chuck or whatever in...
 
I have a Griz go704 with ER collets. I know I gave up height but not having to use the drawbar was worth it to me. I do not use a chuck but use the collets instead. For me it's quick and easy.
 
Like Kuraki, I use an impact on mine as well. It's not that I can't reach, but it makes it a lot quicker and easier. I had bought a HF butterfly impact to make a power drawbar attachment similar to what Saunders Machine Works sells (not sure if they still do or not), but I ended up just using the impact and not making the fixture.

If height is a limiting factor, I'd probably just make a little riser/step next to the machine and stick with the R8 with an impact, but that's me personally. You might also find a power drawbar attachment for your mill that you can put an extended handle on (if using or making one of the cheaper "manual" power drawbar attachments), or if you want to spend a little more on a "professional" power drawbar, they often have a "pendant" style control that will mount closer to your mill quill, and you won't have to ever reach any higher than that to change a tool.

An R8-ER40 collet holder isn't a terrible idea, but for me it'd be too slow, and since I use a drill chuck so often, I'd be using my drawbar for every other tool change anyway, not to mention probably having to change whatever I had in my ER holder in addition to that.
 
ER collets have a wider range of closure then R8 collets. I like ER collets much more then R8 collets in general but normaly thy are used in tool holders. I have been considering using a R8 to ER conversion on my mill as I hate having to reach up and loosen the draw bar. But you will get added runout using a converter. So I just stuck to R8
 
I have a Griz go704 with ER collets. I know I gave up height but not having to use the drawbar was worth it to me. I do not use a chuck but use the collets instead. For me it's quick and easy.

That's cool. To me they're limiting but I don't always change my machinist apron for my knifemaker apron when thinking about it. 20 years of reaching for the draw bar and I don't even think about it.

I have one but I just use it for tapping or holding endmills I don't have an r8 for yet.
 
Thanks for the responses guys! I’m not concerned about the height of an ER collet bc it’s a full size mill. But I’m leaning towards sticking with R8, because no matter whether I’m just changing a tool with the same shank size or having to use another R8 collet altogether, the power bar will loosen it with out having to reach all the way to the top.
 
ER collets have a wider range of closure then R8 collets.

Are you saying the ER collets (ER32) will hold a wider range of sizing than R8? Looking at the collet sets it seems they go up by 1/16" - will they hold all size drill bits with that 1/16" size increment? The R8 collets I've got sometimes won't hardly cover the full 1/16". I've got 1/8", 3/16", and 1/4" R8 collets and some sizes are hard to get the collet to tighten down on good.
 
Ken, ER collets have more range than R8 in 2 ways. The collet itself has more adjustable range, .039" or 1mm, that it will collapse and still hold with minimal run out (they collapse at the top and the bottom vs just one end) and the collets are available in a wider variety of nominal diameters than R8 collets.
 
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