Collet vs. End Mill Holder

[tcarrington]

this has been a very good thread with a range of directions in the discussion. Hopefully back to the why and end mill holder instead of some collet system. I may be beating a dead horse here.
My machinist-for-a-living son tells me they will use a double set screw end mill holder for the higher loads, both feeds and speeds and more likely on larger diameter cutters. They have also used the heat shrink versions as well (don't know which they like better). He is primarily speaking of working some cast form of 4340. Their experience is, yes, it is easier to pull the end mill out of a collet than an end mill holder. This is primarily CAT50 tooling on machining centers. Here we are talking about something that would certainly not be hobbyist and not too likely some something non-CNC machining center. They will also run will flood coolant and at full speed and feed, maybe more.
As a hobbyist, needing less tooling (and it being better) is attractive as I consider adding ER40, ER32, etc for the lathe and mill and dividing head and so on. Since I don't get paid for doing a lot them fast and are running at full entitlement (most of the time) on the speed or feed, and not spinning an end mill larger than 3/4 inch, the R8 seems to be OK. I can also go inside, get a drink of water, come back and reduce the DOC or feed. I also see a case for capability in being able to remove from chuck and then return it with near zero loss of center.

 

[tjb]

P.S. Mike.

To clarify my second question, are you aware of any vendors that sell the Technicks ER32 collets in a kit?

Regards,
Terry

 

[mikey]

Mikey, thanks for the details, I can't help but think that you got more than your share of bad end mill holders.
Considering that there is more machining involved in making ER chucks and collets than in making Weldon end mill holders, I see no theoretical reason why end mill holders can not be made with the same precision. The hole in an end mill holder can be indexed to the side instead of on the axis. Any clearance allowed for insertion of the end mill would have little consequence if the index was on the side opposite the set screw. The Weldon end mills shanks that I have seen are ground to very close tolerances. It stands to reason however that any variation in the shank diameter would have twice the impact on alignment in a Weldon holder than in a collet. I just wish that we could put some numbers on the dimensions we are talking about.
I totally respect that we each arrive at our choices from different experiences. It is fascinating to learn about yours and other persons journey to satisfaction.

The Sherline end mill holder is functional but a joke compared to a real one. It has significant run out because the set screw displaces the end mill to one side. I'm not sure by how much but I learned not to trust it. The end mill holders that came with my RF-31 were premium quality junk. I had to tap the set screw holes to get the chips out. They were nowhere near acceptable quality but they were what I had so I used them. As I tried to explain, I could have gone for better end mill holders but I chose to go with the ER system instead. The key reason has to do with tool life. As I said, for every tenth of run out you have at the tool there is a 10% reduction in tool life. Over time, this will add up and I didn't feel it was a good choice for me if the ER system could beat it.

As for numbers, you have end mill holders so you know what they can do. I've told you what I get with my ER collets, and while they aren't the best they are decent. If you like we can compare numbers. However, I'm not sure what that would accomplish because it comes down to choices we make. I'm already invested in the ER system and am not likely to change. I may purchase an end mill holder or two if I have the need but I don't foresee that happening.

 

[mikey]

Thanks, Mike.
Two sets of questions:
1. Any feel for the range of collets that are available and practical for the ER32 system? What do you consider the extremes in both directions where a larger or smaller system would be superior?
2. Are you aware of any vendors that might sell the collets in kits?

I have had good luck with my end mill holders but I was able to find some very nice ones. All except one are Collis, and the other is a Shars. They strike me as being much more rigid than R8's for larger end mills (5/8" and up), but I also have one for 1/2" - that's the size I've had a couple of instances of end mills slipping in an R8 collet.

I also like your idea of having a thread to canvas our experts on the subject. Seems to me we already have one going right here. Would love to hear the opinions of any others willing to chime in.

Regards,
Terry

Not sure I understand the part about extremes, Terry. A full set of Techniks ER32 collets runs from 7/32 to 3/4" in steps of 1/32" but most other sets run from 1/8 - 3/4". Since most of my tooling falls well within this range, it's good enough. My ER40 goes up to 1", which I have never used yet. My ER20 set goes from 5/32 - 1/2" in 1/32" increments. Again, the chuck I use often has to do with being able to access a feature on the part. In terms of accuracy, my ETM ER40 chuck is the most accurate.

Lots of vendors sell collet sets. I tend to buy my Techniks sets from Amazon because they often have the best prices and have a good support policy if any problems arise. The free shipping helps.

 

[mikey]

this has been a very good thread with a range of directions in the discussion. Hopefully back to the why and end mill holder instead of some collet system. I may be beating a dead horse here.
My machinist-for-a-living son tells me they will use a double set screw end mill holder for the higher loads, both feeds and speeds and more likely on larger diameter cutters. They have also used the heat shrink versions as well (don't know which they like better). He is primarily speaking of working some cast form of 4340. Their experience is, yes, it is easier to pull the end mill out of a collet than an end mill holder. This is primarily CAT50 tooling on machining centers. Here we are talking about something that would certainly not be hobbyist and not too likely some something non-CNC machining center. They will also run will flood coolant and at full speed and feed, maybe more.
As a hobbyist, needing less tooling (and it being better) is attractive as I consider adding ER40, ER32, etc for the lathe and mill and dividing head and so on. Since I don't get paid for doing a lot them fast and are running at full entitlement (most of the time) on the speed or feed, and not spinning an end mill larger than 3/4 inch, the R8 seems to be OK. I can also go inside, get a drink of water, come back and reduce the DOC or feed. I also see a case for capability in being able to remove from chuck and then return it with near zero loss of center.

Lots of pro shops use end mill holders, especially for bigger cutters. Heat shrink is potentially more accurate than an ER setup if you can handle the cost of the equipment needed for that. There is no doubt that slippage is not a problem with a heat shrink set up. On the other hand, the ER system is probably still the industry standard for tool holders.

For a hobby shop, you makes your choices and that's the end of that. I certainly don't have an opinion for what anyone should use. I'm just laying out what I chose and why, that's all.

 

[darkzero]

P.S. Mike.

To clarify my second question, are you aware of any vendors that sell the Technicks ER32 collets in a kit?

Regards,
Terry

I bought all my Techniks collets from either Hemly Tools or All Industrial through ebay. I used to buy from Hemly more but now that my state charges internet tax it don't matter to me anymore, All Industrial is closer to me. Both are reputable suppliers. They sell sets as well.

I personally don't have a need for a full set as I prefer not to use the smallest sizes available for my ER-40, that's where I switch to ER-16. So I bought only the sizes that I needed, just the nominal sizes for tool holding. But if you are going to use ER collets for work holding too it would make sense to buy a set. The Techniks sets come with wood trays.

 

[tjb]

Not sure I understand the part about extremes, Terry. A full set of Techniks ER32 collets runs from 7/32 to 3/4" in steps of 1/32" but most other sets run from 1/8 - 3/4". Since most of my tooling falls well within this range, it's good enough. My ER40 goes up to 1", which I have never used yet. My ER20 set goes from 5/32 - 1/2" in 1/32" increments. Again, the chuck I use often has to do with being able to access a feature on the part. In terms of accuracy, my ETM ER40 chuck is the most accurate.

Lots of vendors sell collet sets. I tend to buy my Techniks sets from Amazon because they often have the best prices and have a good support policy if any problems arise. The free shipping helps.

"Not sure I understand the part about extremes..." You answered it. Curious as to how large (on one end of the spectrum) or small (on the other) before it would be practical to go to an ER40 or ER20.

"Lots of vendors..." You also answered the second question. I did a quick look at MSC earlier and, unless I missed it, they don't sell ER collets in a set. I recognize their prices are higher than I can find on eBay or Amazon, but they and McMaster-Carr can help narrow down the range of what I should shop for.

Thanks once more.

Regards,
Terry

 

[tjb]

I bought all my Techniks collets from either Hemly Tools or All Industrial through ebay. I used to buy from Hemly more but now that my state charges internet tax it don't matter to me anymore, All Industrial is closer to me. Both are reputable suppliers. They sell sets as well.

I personally don't have a need for a full set as I prefer not to use the smallest sizes available for my ER-40, that's where I switch to ER-16. So I bought only the sizes that I needed, just the nominal sizes for tool holding. But if you are going to use ER collets for work holding too it would make sense to buy a set. The Techniks sets come with wood trays.

View attachment 313474View attachment 313475

Oh, very nice. Thanks for the contact info.

Regards,
Terry

 

[BGHansen]

I have both and primarily use the collets, either R8 or E32. I thought about setting up end mills in the holders for quick changes to the various sizes. Thought about recording the tool heights so if Z was set on a certain tool, swapping to another would have a known offset. Something necessary for CNC milling, but not a big deal on my manual mill. I usually set Z by taking the quill to the top of travel, raise the table until it's close, bring the quill down until the tool touches, lock the quill and zero the DRO.

As mentioned above, the head of an end mill holder is usually tapered giving you a little more radial clearance than an R-8 collet or an ER collet chuck.

Bruce

 

[Scruffy]

Unfortunately Crawford/PBA/600 Group stopped making R8 collets years ago. Some can still be found new on ebay but not in the most common nominal sizes. Lyndex are hit & miss for a while now since they moved production to India. Hardinge were too expensive for me. I just went through this search again recently. This time I bought TMX R8 collets made in Italy. Hopefully they are decent. They should be here Friday.