R8 shank with ER32 collet system.

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whateg0
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Re: R8 shank with ER32 collet system.

Post by whateg0 » Wed Aug 09, 2017 10:21 am

If the point of changing were to be to reduce the need to remove an R8 tool from the spindle because of the additional height required, then tightening on the bench makes absolutely no sense. If it's just the added range of tooling sizes, then okay.

Vs. a weldon tool holder, do you really lose that much height, especially in larger sizes where it would matter? If you are using a 1/4" EM, the additional stickout really has little effect. If you are using a 3/4" EM, then sure it has an effect, but a weldon tool holder still sticks out a couple inches. Of course, R8 vs. ER has an advantage there, but I can pull tools out of an R8 collet, so it's a moot point then.

Also, if you have the choice between inch and metric, go with metric. The steps in size of metric collets is about 0.040" whereas the inch sizes are generally 1/16". If you need to grip something like a wire gage or letter drill that's "just" too big for one size, it may be too small for the next size up. I have run into situations where I had to put a drill chuck back in to drill holes like that. Maybe the bigger collets can close more than the ER25 I'm using, but it's worth thinking about.

johnfreese
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Re: R8 shank with ER32 collet system.

Post by johnfreese » Wed Aug 09, 2017 12:17 pm

I use an ER32 collet chuck all the time. As far as tightening, I use a hook spanner with a piece of 1/2" conduit slipped over the handle as a cheater. Usually the spindle brake on me BP is adequate to hold against tightening torque. If I really need to lean on it, I hold the chuck body with a 36mm wrench while pulling on the spanner. I have never found a tightening fixture for R8 so I always tighten in the spindle.

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Richard_W
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Re: R8 shank with ER32 collet system.

Post by Richard_W » Sat Aug 12, 2017 12:47 pm

pete wrote:The one issue I found with my ER-40'S is as far as I know they don't make collets that will hold tool shanks smaller than .094". And below .094" in the ER-32's they only collapse .015" for each collet size verses the .039" for the larger ones. If your ever needing to hold real small drills and tooling then a second set in ER-20 might be needed. They do make the series in as small as ER-8's although I've yet to see them in any tool dealers catalog. I bought inch sized collets since it's still a standard shank size but see no real difference between metric and imperial ER collets and the range of tool shanks they'll hold. Imperial or metric tool sizes are all held equaly well in either type.
The metric collets have the size range written on them. They shrink down about .040". Size on metric collets I have will say something like "9-10" giving you an entire 1 mm range. To cover the entire range as I understand it you would need a 1/32" set of inch collets to do almost the same as a metric set. Still wouldn't go larger than 3/4".

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Richard_W
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Re: R8 shank with ER32 collet system.

Post by Richard_W » Sat Aug 12, 2017 1:12 pm

whateg0 wrote:If the point of changing were to be to reduce the need to remove an R8 tool from the spindle because of the additional height required, then tightening on the bench makes absolutely no sense. If it's just the added range of tooling sizes, then okay.
The point of going to an ER32 is you can hold all sizes of tools in the ER32 range of size. I don't like the idea of changing an ER32 collet in the machine. The R8 spindle is not that strong and I don't see a good reason to use the spindle in place of a vise. You may not agree with my thoughts on this and that is okay. My idea of an R8 shank ER32 collet system is to have more than one and I have bought 3 of them. If you have a power draw bar then its better to change the tool in a vise and its easier then holding two wrenches to change the ER32 chuck in the machine. Also you have the option of preset tools when you do multiple parts. Often I will mix ER32 collets with R8 weldon holders on the same part.

Richard W.

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Richard_W
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Re: R8 shank with ER32 collet system.

Post by Richard_W » Sat Aug 12, 2017 1:19 pm

Ironman1 wrote:To drag this thread off the beaten path, I am wondering if there is a CAT40 holder available for 1" as I have several 1" shank insert type mills that would be nice to use. I guess the option is to get an ER40 collet system as well.
Cat 40 goes up to 1.5" weldon holders. I show this ebay auction as an idea of what is out there. I didn't check around for best price or quality.
http://www.ebay.com/itm/CAT40-END-MILL- ... Sw~gRV1gPW

Do you have the bridgeport type mill with the cat 40 taper? I would love to have one of those.

Richard W.

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Richard_W
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Re: R8 shank with ER32 collet system.

Post by Richard_W » Sat Aug 12, 2017 1:25 pm

johnfreese wrote:I use an ER32 collet chuck all the time. As far as tightening, I use a hook spanner with a piece of 1/2" conduit slipped over the handle as a cheater. Usually the spindle brake on me BP is adequate to hold against tightening torque. If I really need to lean on it, I hold the chuck body with a 36mm wrench while pulling on the spanner. I have never found a tightening fixture for R8 so I always tighten in the spindle.
I don't see why you couldn't use a vise mounted to the bench or make a holder. I intend to make an R* ER32 holder just to change tools. I will just have to put it off for 6 months or longer due to a torn rotator cuff, which means at least 6 months for recovery.

Richard W.

pete
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Re: R8 shank with ER32 collet system.

Post by pete » Mon Aug 14, 2017 12:32 am

Richard_W wrote:
pete wrote:The one issue I found with my ER-40'S is as far as I know they don't make collets that will hold tool shanks smaller than .094". And below .094" in the ER-32's they only collapse .015" for each collet size verses the .039" for the larger ones. If your ever needing to hold real small drills and tooling then a second set in ER-20 might be needed. They do make the series in as small as ER-8's although I've yet to see them in any tool dealers catalog. I bought inch sized collets since it's still a standard shank size but see no real difference between metric and imperial ER collets and the range of tool shanks they'll hold. Imperial or metric tool sizes are all held equaly well in either type.
The metric collets have the size range written on them. They shrink down about .040". Size on metric collets I have will say something like "9-10" giving you an entire 1 mm range. To cover the entire range as I understand it you would need a 1/32" set of inch collets to do almost the same as a metric set. Still wouldn't go larger than 3/4".
Going by Maritools listing for ER 32 collet sets, the metric set takes 18 collets and 20 for imperial to get the full range of sizes. I picked the ER 40's even though a full set in the 32's would have been cheaper and work on the mill a bit better simply because I wanted dual usage from them and they can be used on a lathe for part holding. That 40 size gives me up to a full inch. If I had a 5C collet chuck and collets then I would have picked those 32's for the mill. Holding and trying to use 1" shank tooling on any mill with an R8 taper isn't of much use since you just can't drive anything that size hard enough to make the higher cost of 1" shank tooling worth while.

I have heard on a few forums but not verified by me that some offshore ER collets sets really are metric even when marked with imperial sizes. Apparently the collets are just marked in whatever measurement system you picked. That may or may not be true. My Bison ER's are imperial and they also sell the true metric sets. And from what there website shows for specifications either collet measurement system will collapse the same .039" for each collet. Since I don't think or visualise in metric then buying a metric set of ER's even though a bit cheaper just would have been a pita for me since I'd have to mentaly convert the sizes every time I used one. For the slight difference in cost the couple of more collets needed isn't an issue over having the convenience of not having to convert anything ever. Some can easily work in either measurement system and swap back and forth without any converting. I can't so I have to try to keep my shop tooling in the system I know best.

pete
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Re: R8 shank with ER32 collet system.

Post by pete » Mon Jan 08, 2018 2:55 am

I thought I should add to this since I've found some new information about the torque required to properly tighten ER collets. Maybe partial information might be more accurate. Those high closing torque numbers such as 100 ft. lbs for ER 32 and 130 ft. lbs for ER 40 are only for the largest diameter the collets series can hold. Exactly why that's almost never mentioned with those ft. lb numbers seems strange. Up to now I've been lead to believe the numbers were for all collet sizes within the series. I've seen no actual numbers given yet for the different sizes only that "less torque is needed as the diameter is reduced." I guess if a tool moves in the collet a bit more is needed, and if a solid carbide shank crumbles back to powder then a bit less is needed. :-) Using less torque as the diameter reduces does make logical sense after it's been pointed out, but I wish I'd found that information a long time ago.

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Re: R8 shank with ER32 collet system.

Post by spro » Wed Jan 10, 2018 4:04 am

It does make sense and glad you mentioned it. Even though numbers are huge ft. lbs for collets, it depends upon a few things. I think knowing your machine is the first step. Knowing the spindle is true in its taper and can be checked so many ways before ruined.
With smaller end mills, I don't see the reason for the higher torque except for something else.
Remember; when dealing with precision , it wasn't easy to make it true from the beginning. It wasn't huge torque of the largest size, it was the relationship of that existing taper to collet under reasonable torque to the Size of tool.
Any one of these factors, when disturbed, don't allow the original grip of the taper.
Remember; we are not playing around here. Everything has consequences and this isn't a drill dress. We are mostly getting our feet into a huge thing. Never ever think it was easy. You will lose sight of when every collet cost your week's wage or much more.
I see a huge amount of drawbars being sold. I think we are trapped into using too many things which don't exactly wear the same-but they do.
If it was this easy, the drawbars would be stronger and tighter. That isn't what built precision.

pete
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Re: R8 shank with ER32 collet system.

Post by pete » Wed Jan 10, 2018 6:57 am

If you think about it logicaly Spro (and I wasn't before) then there's a linear relationship between tool shank diameter verses the the collet grip required to resist the cutting forces. I also use my collets for large drill holding so there's likely much more axial load than you'd normaly see with end mills etc. Either way a 1" shank end mill or drill is going to load the collet with a lot more radial and/or axial force than a 1/2" shank tool would. So going by that I can now see where the high torque numbers are needed up at the top of the collet series capacity and no need for maximum torque as the diameter starts dropping. Rego-Fix invented the ER collets so those high torque numbers are from there website. Any of the other good ER collet manufacturers seem to all use the same torque figures. Another guess, but there trying to cover industrial usage where a whole lot more horse power and very high feed rates are going to be pushing the tools to the maximum. With CNC and using cutting tool manufacturers recommended numbers along with load meters showing how hard your pushing the machine I doubt most of us would get very close to those same tool loads on the collets with a manual machine that they do. My mills an R8 taper, I can't push an ER 40 collet system anywhere close to what a 40 or 50 taper machine could even if I had the extra horse power to try it.

A long time ago I started noticing that for high use threads like those drawbars, table travel locks and anything else that got used many times a day they all had higher wear rates on the male and female threads if they were run dry. Adding a few drops of oil once in awhile drasticaly cut those wear rates. A rough guess, but at least by 8-10 times less at least. Since the threads still wear but at a much less rate that oil seems to help flush out any wear particals over time and that probably helps a bit with further reduced wear rates as well. It doesn't take much or needs doing very often, but imo it sure seems to be worth doing. Lead and feed screws get oiled to reduce wear and friction, so how is any other screw thread that gets used a lot any different? I oil the closing nut threads on my ER collet chucks and for the same reason. The collets and chuck taper is mostly kept dry since oil or any lubrication isn't recommended in that area unless you can be sure no lube can get to the collet bore.

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