How do I use ER collets with Bridgeport J Head

I have been researching this but not completely sure I understand it well enough. I make folding knives, and I have a BP mill that would be really nice to be able to use for drilling holes, down to #54. Most of the holes need to be drilled, reamed, and bored for screw head clearance. I do not have a power draw bar. I do have a rotary table I use for cuuting the screw head clearnce to correct diameter, and a few other operations. I made jigs for centering the rotary table, which helped a lot, and more jigs to center work pieces on the RT. Drilling and reaming is done on drill presses, and I transfer work over to the mill to cut the clearance for screw heads. I think I can switch to ER collets and save time/increase accuracy by negating the need for a jig to center the work on the rotary table. If you're still with me, I appreciate it - is this what I really need? If so, what is the best way to adapt the ER collets? My mill has R8 currently. Do I need a new drawbar or what? The collets dont look like they come with anything else.

Oh, in case anyone wonders why I dont just sell my mill and use piloted counterbores, it's because most work is done in titanium and hardened steel. Counterbores are expensive and wear out quickly. Also, I customize screws/stand-offs/lock bars and require the ability to be able to use whatever dimensions I want. Finally, using a mill gives me a better sense of accomplishment and refinement of the end piece - as well as a bigger right arm from turning that drawbar so much. Thanks for any help.

Simple. Just buy a collet holder with an R8 taper, then buy the appropriate collets. Cheapest way is to buy a set.
Depending on sizes needed you can look at ER16, ER32 or ER40. The attached link is just one of many examples...

https://www.aliexpress.com/item/6pc...2795629458.html?spm=2114.40010708.4.96.j2hWiE

I'm not sure if I follow but maybe you are looking for a set like this:
ER25/R8 Milling Collet Chuck Set with 6 Collets - Arc Euro Trade
Accusize - R8 Shank + 15 Pcs ER4 Collet Set + Wrench in Fitted Strong Box, #223-984: Amazon.com: Industrial & Scientific

And a sidenote: Have you considered using boring head for the counterboring?

Thanks for the quick replies! I have never seen a boring head, will look. Actually, I have looked at those before, but they are always for larger sized work when I've seen them. I'll look for a micro, but not sure the advantage over carbide end mills? I bore a 2-56 screw clearance hole to .160", for example. Pockets for bearings are the largest diameters I'm working with on these knives, .505".

wild_musk said:

Thanks for the quick replies! I have never seen a boring head, will look. Actually, I have looked at those before, but they are always for larger sized work when I've seen them. I'll look for a micro, but not sure the advantage over carbide end mills? I bore a 2-56 screw clearance hole to .160", for example. Pockets for bearings are the largest diameters I'm working with on these knives, .505".

Click to expand...

Only advantage is that you don't need custom end mill sizes or to crank the rotary table for arbitrary hole sizes.
Or that's how I imagined that you use the rotary table.

I may be all wrong, but...
I think from Your OP that Your real desire to is speed up production ... rather than perform one specific operation better, more accurate, better finish etc.

A single manual Bridgeport is extremely versatile, and quite accurate on final cuts (of small HP), but very, very slow when adjusting part-at-a-time on one-off setups.

As the others said very well - I agree 100%.
Buy a collet holder with r8 shank etc.. done.
If it is not accurate enough
1. not accurate enough..
Make an adjustable ER collet head mount, like a 4-jaw or 6-jaw independent chuck.
1 day job, at most.
You will never take off the head, and marked/indexed positions = witness lines in the head/collet chuck can/will repeat very well if You do, ...

2. accurate enough ..
(likely imho, You seem to look for Very Good manual accuracy vs a drillpress, thus 0.001" or one thou is plenty, thus any ER collet system (good) is plenty, thus ...)

You still need to get the jobs to the tool well enough.
Likely, Your BP mill is vastly more accurate in repeatability than anything else in the system.

My suggestion, for fast jobs/locating/accuracy.
Fwiw..
Find a way to have a tapered hole(s) in the blank/workpiece/billet.
Forget the drill-press all together (or not. One could make the tapered hole.. and then all else is referenced off it).

Locate on the tapered hole, with a tapered locating pin in the BP ER chuck.. and workpiece loose, on 2 semi-loose clamps.
Press down on quill, workpiece will get into position, to within about 0.01 mm, or 0.0005", or half a though.

Lock-quill that still holds the workpiece in position, quarter-turn fast-clamps, its now in-position, perfectly aligned, total time perhaps 10-30 seconds.
Fast setups like this did 2-5 secs/workpiece on any nr of production setups in the manual past.

Secondary advice.
Index everything off Your BP, first-position location.

You can make adjustable stops via bolts, better to use specialty high-quality 3a/3b bolts/nuts if you can find some, or make some, with some tiny adjustments possible.
This will give you very very repeatable hard-stops of very low cost, very high repeatability.
You can industrial-epoxy (locktite/hysol 3784 iirc) the nuts/stop in, since they wont hold any force.

Cheap 2-micron jigs:
Any nr of 10$ electric bits can give You 0.01 mm or (much) better "nearly-there" lights/buzzers, if You want to go better in repeatability.
Any 10$ electronic opto, with a debris protected fence/knife-edge, repeats to about 1 to 2 microns, and a 10$ cellphone charger for 5-12 $ DC.
Put in 3, one for near, one for past, one for *there*.

It is very very hard to build extremely accurate stuff off-the-system with no external checks, probing, calibrating, adjusting, thermal comps, etc.
It is relatively easy to adjust Your stuff to repeat to extremely accurate dimensions.
Anyone skilled can make simple stuff to about 2 microns in repeatable size, given a standard, samples, some time.

Non skilled people were doing this from 1940 on-wards, once gage blocks appeared.

Thus...
Your BP head will not repeat in Z to a great extent ... to any (high) accuracy on dials.
But once set to "an" accuracy, variation between identical pieces with identical feeds/speeds/tools can be minimal.

For YOU and anyone making their own stuff, it is totally irrelevant weather the spacing between 2 holes, high precision locating stuff, is say 40.000 mm or 40.100 mm.
(Huge error as a sample only. In practice, more like 0.3-0.5-1 thou, or 0.025 mm max, over 40 mm length, on a BP).

As long as they all repeat, You are happy, as are Your parts/customers etc.
And when You use YOUR gages, YOUR hard stops, and YOUR near-in-far indicators, YOU can repeat to 10x better accuracy than anyone can theoretically "make" stuff on a BP.
Make multiple sets of each, identical setups, to have repeatable hard gages, or adjust off electronic micrometers.


I did not say accurate sizes/gages to 2 microns, I said repeatable, .. Your setup might have all sorts of bias here or there, but it is immaterial, as long as it repeats.
HTH...
And I hope I was not boring, or did not come across as a besserwisser..

A lot of people that have ER set ups profess as if they are the only thing a person needs for a milling machine, they are a good system but definitely not the snake oil for every occasion. I have found that I need to throw the whole arsenal at some of the jobs I get so I have ER in several series sizes, Acura Flex in a couple of series sizes, DA collets in several size series plus a big TG chuck with collets to suit and have 2 different milling chucks with bushing to fit fractional end mills.
If you want fast get a quick change setup for the R8 spindle and several holders or better yet, change the spindle to a Universal Quik Switck with a fist full of holders. ER collet chucks aren't necessarily fast to use but do have many attributes; They don't have to be permanent in the spindle though, straight shank varieties are abundant in many sizes and can be held in standard tool holders with slight loss of accuracy. I use them all the time for close work next to a wall or deep in a pocket but for accuracy I try to hold them directly in the mill spindle with a collet.
Dan

Danny VanVoorn said:

If you want fast get a quick change setup for the R8 spindle and several holders or better yet, change the spindle to a Universal Quik Switck with a fist full of holders.

Click to expand...

+1

My go-to, and still made in USA, is the PDQ-Marlin family, largely because I inherited a nearly-complete set with a mill I bought some years ago, easily filled in the blanks thanks to a generous PM member with a few 'spares'.

I've no klew how PDQ compares to Quick-Switch, TIR-wise, but the concept is what matters.

ER, TG, et al are MEANT to be 'set' off-line in a fixture on a mounting with a standard 'tail' such as NMTB/CAT/BT 40 or 50, HSK, Capto, etc. These are provisioned in large count. They will be swapped on fast-mover CNC machines by automated tool-changers out of large magazines. Collet nut is touched seldom. VERY seldom. Whole shebang is swapped instead.

Soon as you start dicking around with manual loading any of these onto a Bee Pee's R-8 'tail', the only advantage they HAVE LEFT is the ability to accommodate a wide range of sizes for a small count of collets.

Bee Eff Dee.

ER/TG, etc. should be second, third, even FIFTH choice as to how you tool that manual machine where YOU are the "automated toolchanger". A 'now-and-then problem solver' these are, IOW, never your first-choice "productivity" solution.

Time is money. I say you don't need ER-system or drawbar-fuckery AT ALL.

Get you something that lets you change tools faster, at the nose, with only a partial-spanner-turn, no need of a torque wrench, and with less need of having to drop Z-axis, or aside and then return on X or Y or 'rotab' to gain enough daylight to get tooled-up holders in and out.

Moving ANYTHING mid-operation that you can AVOID moving wastes time, damages tooling, ruins materials, or some combination thereof.

Minimal swap clearance required happens to be the main reason I like PDQ-Marlin - as little as 3/4" needed, regardless of drill or mill length.

Try matching THAT with anything at all that wants an R-8 tail pulled clear-out to swap tooling, and a light comes on "Real Soon Now".

Get CNC.
.....

I have a BP Clone that I bought new with a 3 axis DRO. First avoid R8 Collets, they grip only on the outside end of the shank and are crap. My go to collets are ER, they grip across the whole shank and do not slip. Secondly, when I want to drill accurately, I try to use a collet to drive the drill bit, never a chuck. ER collets are readily available and inexpensive. They also come in both inch and metric sizes. I use ER32 and ER40 mostly.

MattiJ said:

Only advantage is that you don't need custom end mill sizes or to crank the rotary table for arbitrary hole sizes.
Or that's how I imagined that you use the rotary table.

Click to expand...

Man, yeah, I can see that now. If I had them for a few standard screw head or bearing sizes, that would be much faster.

Since you're talking about small tools, just get yourself an ER straight shank extension. An ER16 will go up to .390d dia, with a 3/4 OD.

Why don't you put a nice small drill chuck in your mill? You don't need ER collets for drills. They are very accurate but very slow to change.

A GOOD drill chuck, I mean one that is concentric and stiff, will handle the drill head counter boring with end mills also. this will REALLY speed you up.

Add a digital quill depth gauge and you will think you have died and gone to heaven.




sensitive drill - Google Search

dsergison said:

Why don't you put a nice small drill chuck in your mill? You don't need ER collets for drills. They are very accurate but very slow to change.

A GOOD drill chuck, I mean one that is concentric and stiff, will handle the drill head counter boring with end mills also. this will REALLY speed you up.

Add a digital quill depth gauge and you will think you have died and gone to heaven.




sensitive drill - Google Search

Click to expand...

Poor mans solution to work faster with ER collets is to keep the nut and the tool on the collet and buy as many nuts and collets as you need tools. Faster than reaching for manual drawbar op.

a Royal R8 quick change setup would be ideal.... very pricey though. they have er-series , DA (for drilling/tap
only) , and drill chucks. start @ $1500 for a new basic set w/ toolholders...Royally expensive.

there were Japanese Nikken and Yuasa quick change R8 systems. might do well to find a used set for $300-$500 .
i doubt they still make them, but you can bet they would not be inexpensive .

lots of B.S. "quick change " out there - just an r8 collet chuck... you'd be faster with an r8 power drawbar
and several preset r8 collet chucks and drill chucks .

Hanermo, thanks for the information, Greatly appreciate it. It gives me a lot to consider when I finally decide on dedicated designs. Most of the time there is a fair amount of leeway for pivot or screw locations, as long as like you said, they are repeatable. I don't use CAD to design...the main goal is that it pleases the eyes and hands. Hopefully I understood you well enough and thanks.

John Welden said:

Get CNC.
.....

Click to expand...

Thats just cheating

dsergison said:

Why don't you put a nice small drill chuck in your mill? You don't need ER collets for drills. They are very accurate but very slow to change.

A GOOD drill chuck, I mean one that is concentric and stiff, will handle the drill head counter boring with end mills also. this will REALLY speed you up.

Add a digital quill depth gauge and you will think you have died and gone to heaven.




sensitive drill - Google Search

Click to expand...

Thanks...I have a Jacobs on an R8 shank, but have not had the best of luck with it. I have used it to locate screw hole or even drill them, then switched to an end mill to counterbore, and I have ended up with excessive clearance on one side. Non-concentric flaws are easier to see. I never tried it for milling because I've always heard it was bad for the chuck.

Monarchist said:

+1

My go-to, and still made in USA, is the PDQ-Marlin family, largely because I inherited a nearly-complete set with a mill I bought some years ago, easily filled in the blanks thanks to a generous PM member with a few 'spares'.

I've no klew how PDQ compares to Quick-Switch, TIR-wise, but the concept is what matters.

ER, TG, et al are MEANT to be 'set' off-line in a fixture on a mounting with a standard 'tail' such as NMTB/CAT/BT 40 or 50, HSK, Capto, etc. These are provisioned in large count. They will be swapped on fast-mover CNC machines by automated tool-changers out of large magazines. Collet nut is touched seldom. VERY seldom. Whole shebang is swapped instead.

Soon as you start dicking around with manual loading any of these onto a Bee Pee's R-8 'tail', the only advantage they HAVE LEFT is the ability to accommodate a wide range of sizes for a small count of collets.

Bee Eff Dee.

ER/TG, etc. should be second, third, even FIFTH choice as to how you tool that manual machine where YOU are the "automated toolchanger". A 'now-and-then problem solver' these are, IOW, never your first-choice "productivity" solution.

Time is money. I say you don't need ER-system or drawbar-fuckery AT ALL.

Get you something that lets you change tools faster, at the nose, with only a partial-spanner-turn, no need of a torque wrench, and with less need of having to drop Z-axis, or aside and then return on X or Y or 'rotab' to gain enough daylight to get tooled-up holders in and out.

Moving ANYTHING mid-operation that you can AVOID moving wastes time, damages tooling, ruins materials, or some combination thereof.

Minimal swap clearance required happens to be the main reason I like PDQ-Marlin - as little as 3/4" needed, regardless of drill or mill length.

Try matching THAT with anything at all that wants an R-8 tail pulled clear-out to swap tooling, and a light comes on "Real Soon Now".

Click to expand...

Yes, these are my issues...every time I move the work or locate with a jig, I sacrifice accuracy for speed. I break a tool, or forget to center the table before I center the work on the table...etc. I will have to see if the expense is worth it for my shop, but this is what I feel to be the heart of the issue. Thanks for the suggestions and your time.

tnmgcarbide said:

lots of B.S. "quick change " out there - just an r8 collet chuck... you'd be faster with an r8 power drawbar
and several preset r8 collet chucks and drill chucks .

Click to expand...

Thanks, I may end up doing exactly this if legit QC is cost prohibitive. I've had pwr draw bar plans sitting around, just keep prioritizing them under other things...