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J Tiers
09-14-2007, 11:12 PM
The recent thread on the drill grinding article, and the things brought up in reply, made me think some more.

The big issue with collet drill holders is the need for a half billion different ones. Most collets are only able to handle closely sized parts.

But the ER collet is supposed to handle a relatively large range, and would potentially be ideal for this use. They are accurate enough in centering, readily available, and easy to use ( I presume).

The big problem is the total lack of a thru hole in the holders. That might be fixable by modifying the holder.

But as a drill holder for sharpening, it seems they should be very good. They might even hold over the flutes acceptably.

That would eliminate the need for the V-notch, and toggle clamping, etc, as shown in the article. A simple alinement jig such as the one illustrated in the article, and a two-sided holder base would allow essentially the same type operation, with the improvement that there COULD be a stop used, since positioning would be totally consistent.

DR
09-14-2007, 11:15 PM
The big problem is the total lack of a thru hole in the holders. That might be fixable by modifying the holder.



That's not a universal problem, many ER holder have holes through the shank.

lane
09-14-2007, 11:24 PM
There is all ready one on the market . Uses 7 collets to hold from .060- 1/2 inches. Most ER holders have a thru hole.

J Tiers
09-14-2007, 11:53 PM
There is all ready one on the market . Uses 7 collets to hold from .060- 1/2 inches. Most ER holders have a thru hole.

Heck, there are already drill sharpeners on the market also..........

Not long ago, the chorus was "ER holders have no usable thru hole".

Now the chorus is "whatcha mean? Thay ALL have thru holes.......

Go figure.........

Paul Alciatore
09-15-2007, 12:00 AM
I like the ER collets and am in the process of making a holder for my Unimat and ER-11s. Also, I see no basic reason why there can not be a through hole. In the case of my design, it would almost be harder to block the back.

I also read the article and have been thinking about drill sharpening. And this is not the first time the subject has crossed my mind. I WILL build or buy a sharpening machine. Soon I hope.

I do see one additional drawback to using the ERs and that is cost. A good set of ER-11s cost me almost $150 and they only go to a bit over 1/4". I don't know if I can justify several hundred dollars for a larger sized set that may not get me much past 1/2". And that's just the collets, not the holder or any of the rest of the sharpening machine.

I had a thought this afternoon. Instead of a collet or a single Vee holder, what about a series of interleafed Vee shaped fingers. You could make a bunch (12-20) of rectangles about 1" X 1.25" X 1/8" or even thinner. Then stack them and simultaneously cut a Vee shapped notch on one of the 1" edges, corner to corner on all of them at once. It would be big enough to hold up to a 1" drill and, with care in cutting the Vee, there is no lower limit to the size. You would also need an equal number of spacers about 0.5" X 1" X 1/8"+. The 1/8"+ would be 0.128" or so for clearance.

Now divide them in half and use each half to make two sides by stacking Vees and spacers alternatively. For maximum accuracy, you would keep the Vee pieces in the same orientation as when they were cut (in a stack). One stack would start with a Vee piece and the other with a spacer. Tie the stacks together with cap screws while a piece of drill rod is used to align the Vees. Now rotate one stack 180 deg so the Vee ends of the two stacks intermesh. Any errors made while cutting the Vees will be symetric and will cancel out so when the two are closed together with a drill in the central square shaped opening, the drill will stay very well centered both vertically and horizontally in the pair.

You need a box shaped frame aroung them with adjusting screws on both sides to close these Vee jaws. I would think 3/8" or 1/2" flat ground stock.

This holder should be able to hold drills from #60 or less to 1" or more. They would be automatically centered vertically and an optical jig could be used to allow you to center horizontally by flipping the holder over and comparing the location in each orientation. Tighten the screws on each side like centering in a four jaw chuck, but easier as you only need to center in one direction. This holder will also provide the 180 degree indexing for sharpening the two flutes by simply flipping it over.

That's as far as I have gotten with this idea. So far anyway. I need to buy/make a diamond wheel grinder to use with it. And some accurate way of positioning the holder to make split point drills.

John Stevenson
09-15-2007, 04:52 AM
I have been pushing ER collets for years, hence the spin indexer with combined 5C and ER capabilities,

http://homepage.ntlworld.com/stevenson.engineers/lsteve/hidden/ER%20spin%20indexer.jpg

An adaptor from 5C to ER32,

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/5CER2.jpg

and the test X3 mill that has ER32 direct into the spindle.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/beltdrive3.jpg



As far as I recall it's only JT who keeps saying ER's have no thru hole in the holders.

Paul, It's possible to buy small ER11 chucks and a set of good collets for far less than that if you look around.

I have about 3 of these sets in the workshop, one is fitted with a thread at one end so it can be held in a threaded Clarkson chuck, one has a keyway machined down the side and is held in a bushed and spring loaded spindle for engraving and one is just held in a 16mm collet for small cutter work.

.

S_J_H
09-15-2007, 10:45 AM
I really like ER collets. They work great in my mill and lathe. And the ER collet chucks are pretty easy to make as well. I made this thru-hole, screw on ER32 chuck for my lathe.
http://i109.photobucket.com/albums/n48/S_J_H/9x20%20mods/39x4gearsetup009.jpg
http://i109.photobucket.com/albums/n48/S_J_H/9x20%20mods/39x4gearsetup008.jpg
http://i109.photobucket.com/albums/n48/S_J_H/9x20%20mods/39x4gearsetup011.jpg
Steve

J Tiers
09-15-2007, 11:01 AM
As far as I recall it's only JT who keeps saying ER's have no thru hole in the holders.

I am not sufficiently motivated to "prove I am right" to go and search out prior posts..... I seem to recall others TELLING ME that there was no hole, when I asked (note I asked, and did not declare).

I look in the catalogs, and I see ER holders on R8, straight shanks, or whatever, and they seem to obviously have no thru hole. At least if they do it don't come out the back...... so it seems to be true, at least in the US.

But the US is resistant to the dictates of our old imperial masters in europe, so maybe we get bad "punishment" ER holders, just like only the most horrible "punishment" clunky metric screws etc also.....

I am simply parroting what I was told by folks right here about ER, so if that is wrong, somebody better look in the mirror for the problem.... :D

The expense for ER is certainly a lot. A set of Jacobs rubberflex and a holder might be fewer collets and a wider range. But I always see the huge handwheel Jacobs holder, was there a smaller one also?

japcas
09-15-2007, 12:10 PM
IThe expense for ER is certainly a lot. A set of Jacobs rubberflex and a holder might be fewer collets and a wider range. But I always see the huge handwheel Jacobs holder, was there a smaller one also?

Here is an older rubber flex collet holder that uses a key like a jacobs chuck to tighten. I like it a lot.
http://i32.photobucket.com/albums/d39/japcas/DSCN0609.jpg

chrisfournier
09-15-2007, 01:01 PM
I have been at the HSM game for a couple of years now - first a lathe and now a Nichols horizontal mill with a vertical head based on 40 tapers. I owe my start to a life long machinist and model builder Reg Miller, thanks Reg!

Once I had the mill at home I did a fair bit of head scratching to figure out how I was going to hold tools in this mill. In the end I went with an ER40 system because it is good up to
1" and it was robust. I went the Chinese route for these collets and holder because it was affordable - I have no regrets...

I recently refitted a woodworking shaper that was built to accomodate 3/4" cutters only. I made a new spindle for the machine using an ER40 collet system - one trick pony! Now with three collets my shaper can use router bits and shaper cutters. My time is worth - well - nothing as all my friends with "small interesting jobs" tell me so I was able to get this shaper up with greater capacity for less than $200 in materials.

I recently bough a 5C kit with spin indexer etc. and am going to build the Loop collet chuck for my lathe.

Imagine my horror when I looked at the ER lathe chucks on this thread - why hadn't I thought of that? What a simple and elegant tool solution. Oh well I guess that you can't have too many collets. I will go metric on the lathe with the 5C collets because they are less expensive.

http://i157.photobucket.com/albums/t72/chrisdfournier/IMG_0390.jpg
http://i157.photobucket.com/albums/t72/chrisdfournier/IMG_0430.jpg
http://i157.photobucket.com/albums/t72/chrisdfournier/IMG_0434.jpg

Peter N
09-15-2007, 01:12 PM
Actually, the ER holder I use on my Bridgy doesn't have a through hole.

The holder itself was a cheapie bought from J&L a couple of years back to go with a nice set of german made ER collets I got.
Maybe it's just the 'budget' ones that don't have a hole through?

Either way it's a very good system, it's made my drill chuck redundant, and I hardly ever user the standard R8 anymore unless I need the extra headroom under the spindle.

Peter

TGTool
09-15-2007, 01:26 PM
ER collets have a lot to like. Through holes are the responsibility of the adapter, not the collet, and the front closing means no through hole space comandeered by a drawbar. They're straightforward to adapt for - one tapered cavity and one external thread. I usually do ER-32 adapters for Atlas threaded spindles (and M39 x 4.0), but it could be ER-40 if preferred, and the larger body allows it to be adapted to larger spindle threads too.

What could be easier than this.

http://i48.photobucket.com/albums/f244/TGTool/ER-40Adapter.jpg

dp
09-15-2007, 02:29 PM
I have about 3 of these sets in the workshop, one is fitted with a thread at one end so it can be held in a threaded Clarkson chuck, one has a keyway machined down the side and is held in a bushed and spring loaded spindle for engraving and one is just held in a 16mm collet for small cutter work.

.

Is that a shop-made adapter or is it available for purchase? Odd this should come up as I'm on my way to Boeing surplus to look for some kind of spin indexer and or collets and carbide chips. I have several pending projects that require indexing and now that I'm unemployed I have time play in the shop.

Peter N
09-15-2007, 02:38 PM
I think John 'invented' that adaptor, and it's now commercialised over here via Arc Euro Trade:
http://www.arceurotrade.co.uk/

Click on 'latest' and scroll down a bit.

Peter

Paul Alciatore
09-15-2007, 04:09 PM
Sir John said,

"Paul, It's possible to buy small ER11 chucks and a set of good collets for far less than that if you look around."

Yes, I did look around. And there are ER11 sets for under $100. But I didn't want to go completely cheap and regreat it later. Hopefully it is a once in a lifetime purchase.

As for the through hole thing, I highly doubt that there is anything preventing a hole from being drilled in almost any of the collet holders or adapters except the hardness of the steel. Come on guys, we aren't helpless. Break out those carbide drills or boring bars and remedy that situation. As I said above, in the holder I am making it is almost harder to block the center hole than to have it.

J Tiers
09-15-2007, 05:39 PM
Many/most holders I have seen in catalogs are on a taper or straight shank, and those have less room for a hole. It might also be harder to drill.

The 5C adapter is obviously an exception, and presumably allows any hole the 5C does.

Will the ER grip on the drill flutes OK? I would think so, as they are fairly long as far as grip length. That was a question I didn't know the answer to.

lazlo
09-15-2007, 05:48 PM
Yes, I did look around. And there are ER11 sets for under $100. But I didn't want to go completely cheap and regreat it later. Hopefully it is a once in a lifetime purchase.

There are several guys on PM who are pretty unhappy with the Chinese ER collets from Discount Machine, Enco and such.

I picked up a used set of ETM ER-16 collets, and they're all dead-on (less than 2 - 3 tenths runout at the "nominal" diameter).

I got a brand new ETM R8 ER-40 chuck on Ebay, and I've been patientily waiting for a good deal on ER-40 collets... There's a guy on PM who sells no-name ER collets on Ebay, and he's gotten pretty good reviews, so I may try that.

Alistair Hosie
09-15-2007, 06:09 PM
nice workmanship Steve well done regardsAlistair

dp
09-16-2007, 12:31 AM
I think John 'invented' that adaptor, and it's now commercialised over here via Arc Euro Trade:
http://www.arceurotrade.co.uk/

Click on 'latest' and scroll down a bit.

Peter

I was mulling the idea of fab'ing one in my shop and decided to look up the dimensions of a 5C collet and damn if that's not harder to find than moon rocks. Lots of sites have the basics: 1.25 diameter, 10 degree taper, overall length, thread diameter and pitch, but nowhere can I find the length of the threaded section nor the dimensions for the slot at the threaded end. I thought that a bit odd given their ubiquitousness.

Anyway, the reason I was looking is that I have a set of collets but they are not ER anything. It is the H2690 with the MT3 taper here: http://www.grizzly.com/catalog/2007/Main/608

And since I'm thinking of getting the 5c spin indexer on that same page I figured I'd use my existing collets. But what a pain trying to get size info, though.

crrmeyer
09-16-2007, 01:11 AM
I always wanted to take one of these and bolt it to a bigger lathe's faceplate.

http://littlemachineshop.com/products/product_view.php?ProductID=2532&category=

dp
09-16-2007, 01:15 AM
I always wanted to take one of these and bolt it to a bigger lathe's faceplate.

http://littlemachineshop.com/products/product_view.php?ProductID=2532&category=

That, in fact, is something I'm going to make after I get the spin indexer. The metal is sitting on my workbench now just waiting on me.

nheng
09-16-2007, 09:55 AM
That's about the same price for a similar and very fine Austrian made unit from Emco (Blue Ridge Machinery). On the Emco, TIR is about 0.0002" at the taper. It is, however, specifically for the Emco tapered spindle nose with 3 bolt pattern (Compact 8, Maximat 7, 8.4, 8.6, and others??).

If you want to build your own, either buy a nut from ETM (or others) that incoporates a floating ring for the eccentric shoulder, or try to include a similar feature.

What it does is allow the collet to be "popped out" easily without turning it or rubbing hard on the collet groove. In any event, anything that pops the collet out with about a turn or so of loosening is well worth doing.

As far as a thru hole, that's been pretty well covered. The Emco and similar spindle mounted chucks have a thru hole, straight and tapered shank chucks generally do not, longer shanks for drill holding can have deeper bores. Several friends run ER-16 long, straight shank holders for CNC drilling on small parts.

lazlo
09-16-2007, 11:34 AM
I was mulling the idea of fab'ing one in my shop and decided to look up the dimensions of a 5C collet and damn if that's not harder to find than moon rocks. Lots of sites have the basics: 1.25 diameter, 10 degree taper, overall length, thread diameter and pitch, but nowhere can I find the length of the threaded section nor the dimensions for the slot at the threaded end.

You can get those measurements off a 5C collet: the threaded section is 9/16", and the slot is 0.1"

If you look at the 5C drawings at the Dunham and Hardinge sites, you can get the rest of the dimensions. One of these days I'll draw it up in CAD:

Dunham:
http://www.dunhamtool.com/images/5c-draw.gif

Hardinge:
http://www.hardingetooling.com/imagegallery.asp?curpage=1&ID=1001

http://www.hardingetooling.com/imagegallery.asp?curpage=2&ID=1001

dp
09-16-2007, 12:39 PM
Thank you, Lazlo - I don't have a 5C collet to measure, and because I'm looking at building an adapter so I won't need 5C collets, I probably won't buy any. My lathe and mill are really too small for them.

The missing parts of your drawing are the gap width/depth for the thread clearance (probably a simple pragmatic value will do), and there's no alignment slot on the threaded end in your image nor dimensions for it. So I have more information (threaded section is 9/16" which I presume includes the gap - haven't checked the math to get the length of the 10 degree shoulder section) but still haven't found all the information. I did already know the barrel diameter is 1.250". I won't need the radius of the collet face as that will be turned and threaded to hold my existing collets.

I guess my point is that while I can reverse engineer one if I have it in my hand, I've found it interesting that I've yet to find a single complete definition of the geometry of these collets and I'm pretty darn good at googling :)

nheng
09-16-2007, 03:28 PM
DP, There's a good reason why you haven't found all the information on the web. Someone owns it.

A courteous call to Hardinge tech support should get you the dimensions and tolerance on the 1.25.. diameter, and it's a good idea not to publish it.

It is the reason that Hardinge collets fit properly and various imports do not ... well, at least one of the reasons. Den

J Tiers
09-16-2007, 04:07 PM
Or, it could be that Hardinge just actually makes them to spec......

A survey of hardinge collets would very soon lead to an accurate value for every tolerance they use. it simply isn't that hard.

I have done "reverse SPC" before, and it works.

John Stevenson
09-16-2007, 04:28 PM
DP, There's a good reason why you haven't found all the information on the web. Someone owns it.

A courteous call to Hardinge tech support should get you the dimensions and tolerance on the 1.25.. diameter, and it's a good idea not to publish it.

It is the reason that Hardinge collets fit properly and various imports do not ... well, at least one of the reasons. Den

That depends on who you use for imports.
Rest assured the Chinese have copies of all the specs that we have to pay serious coin for.

As an example we send a drawing and sample to the Chinese, They then redraw this using some of our data and known specs and send it back for checking.

When it comes back it has tolerances on that were not on our original drawing, it also has surface finishes on that were not on either so they know just what is what.

The collet bearing surfaces come back with a 4 u/in finish marked on them, all other ground surfaces are 8 u/in, even the ones that don't matter.

Somewhere I have the specs for the 5C as defined by the company we use and they are good. All their machinery is less than 2 years old and Swiss made.

Any spec you want, Camlocs, DiN's, A series etc, they have them.

They are getting better and better at giving the customer what they need. The reason there are discrepancies is that sometimes the main suppliers send a collet over to China and ask for this to be copied and it has to cost no more then $0.xx each.
The problem is and this is where all the bad R8's came from was the US dealer sent a bad collet over as a sample so he got bad ones back.
The Chinese company also sold to other dealer who were price conscious and so this went on. Which proves you only get what you pay for.

.

Forrest Addy
09-16-2007, 05:00 PM
The problem with holding drills is not so much the collet but registering the margins of the flutes and the back taper so they lie concentric to the sharpening axis. Since drills commonly have about 25 degrees helix and the margin land being so narrow, it's difficult to ensure concentericity at 90 degrees to the margin. You need a collet having a grip at least 1/4 the length of the lead and ideally more.

In most cases careful insertion and eyeballing the result will get you close enough to grind a drill. ER collets with their long grip are almost ideal for this purpose until you approach the diameter capacity of the range. Then the collet length will impose restrictions.

Gripping a drill at the extremes of the collet's accommodation results in a lobed grip. If the lobes happen to work out to suit the drill's helix well and good. If not then the grinder hand will have to work some expedients like a single layer paper shim.

I mentioned back taper. There is a standard for twist drills and one easily overlooked characteristic common to twist drills (and endmills and taps, for that matter) is the back taper. Depending on diameter the size over the lips may be several thousandths larger than the size near the wash-out of the gullets. This also affects the quality of the grip. Close contricity is seldom a concern in routine sharpening twist drills but should problems arise the hand at the drill sharpener should be aware of these refinements so quick and rational corrections may be taken.

Back taper. Takes me back to my working days. Supervisors and snappers hate allegedly qualified people who bring them mysteries. "I dunno, boss, I can't seem to make it work." Drove me nuts whenever I heard it. It usually formed the beginning of a weeks long education towards independent thinking, concepts of fact based judgement development, and learning to draw reasonable conclusions from insufficient data. Soon as I get the guy smartened up he's snatched off to save the technical bacon of fatuous but well-connected dweebs.

moldmonkey
09-16-2007, 05:28 PM
dp-Check out 5c fixture mounts (http://www1.mscdirect.com/CGI/NNPDFF?PMPAGE=1597&PARTPG=N2DRVSH&PMT4NO=0&PMITEM=09744251&PMCTLG=00&PMT4TP=*LTIP) They have a hardened & ground shank with a soft head. That would save alot of work.

John Stevenson
09-16-2007, 05:35 PM
Actually page 1597, two in front of the link.

We have them over here as well and that's what I made my first 5C to ER32 nose out of, why re-invent the wheel ?

I have another of these 5C converters in the works at the moment but it will probably only appeal to UK owners of machines - still on the 'secret' list.

lazlo
09-16-2007, 05:42 PM
From http://www.hardingetooling.com/faq.asp


I am trying to drill a very accurate hole using a DA-style collet system without any success. Any suggestions?

Here are several things to consider. Extremely accurate drilling requires a very good holder and collet. With the considerable flexibility of the DA, TG, and ER Collets, we tend to forget the cardinal rule for collets: the bore of the collet should be the exact size of the diameter being gripped for the best TIR and gripping force.

Therefore, for extremely accurate drilling, the collet bore should be the same size as the shank of the drill. Second, if you have a choice of holders, it is best to use the ER collet holder over the DA collet holder. The DA holder is a double-angle holder, with a closing angle on the front and back of the collet. The theory is that the collet will close parallel to the centerline of the holder. Unfortunately, it is very difficult to manufacture a holder and collet that accurately mate. For standard drilling tolerances, this usually is not a problem, but can be when doing extremely close tolerance drilling. The ER is considered a single-angle collet because the major closing angle is long and shallow. This results in better concentricity than the double-angle system. The TG collet system is better than the ER system because it has an even shallower closing angle. Unfortunately, this system is usually for larger shanks and most holders that use these collets are for vertical machining centers.

lazlo
09-16-2007, 05:51 PM
Actually page 1597, two in front of the link.

John, moldmonkey's link is correct (page 1597 of the MSC catalog) -- the UK version of the MSC link must be going to a different page.

Enco has the same 5C Fixture Collets for $10 less than MSC's price -- I just ordered two of the 2" x 2" collets to make Frank Ford's driving center:

http://www.use-enco.com/CGI/INPDFF?PMPAGE=329

John Stevenson
09-16-2007, 06:03 PM
You have a better choice than we do.
We only get 2" , 3" or 4"

http://www.arceurotrade.co.uk/en-gb/dept_184.html

.

lazlo
09-16-2007, 06:17 PM
You have a better choice than we do.

That's 'cause the Brits defected and use that funny metric crap now :D

Seriously, your prices are better than Enco's: 12 (including VAT) for the 50 mm x 25 mm collet is $24 USD, and Enco's price for the 2" x 1" is $35, MSC's is $45.

lazlo
09-16-2007, 06:23 PM
The Arceurotrade (UK) 5C clutch collets look like the Shars collets (here in the US).

Shars has the 2" 5C clutch collets for $17, but they're only 1 1/8" deep, which doesn't seem deep enough for a ER collet chuck, and borderline for a Frank Ford-style drive center.

http://www.shars.com/images/catalog/pg84.jpg

dp
09-16-2007, 07:00 PM
DP, There's a good reason why you haven't found all the information on the web. Someone owns it.

A courteous call to Hardinge tech support should get you the dimensions and tolerance on the 1.25.. diameter, and it's a good idea not to publish it.

It is the reason that Hardinge collets fit properly and various imports do not ... well, at least one of the reasons. Den

Thought that design had been around long enough for patents to have expired but copyrights would explain it. But thanks - I do see the problem now. I'd wrongly taken it to be an open standard.