Tool holding on a Bridgeport

SamI

SamI

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I’m sure that this has been asked many times before and I’m sure I’ve read up on it a few times but can I find the information I want now?!

As some of you may know from another thread I have recently bought a Bridgeport mill. With it came a few boxes with probably a couple of hundred end mills. Unfortunately though nothing to hold them other than a fee R8 collets.

Now my budget is quite limited just now but I am wanting to get some tool holders for it. I know there are various options from R8 collets, an R8 to ER32 adapter or even some of the quick change variants.

I like the idea of a quick change system but as I said before my budget just now is limited. I don’t however want to invest in one system now just to replace it all down the line.

So my question is, which is the most convenient and / or versatile tool holding solution for a Bridgeport? Are there any trade offs for a quick change system? Presumably rigidity could suffer but is this really a problem given that the R8 collet itself would possibly be the weak link?

Thanks in advance!
 
The R8-ER32 is nice because you are not reaching up and changing R8 collets all the time. You can even eliminate the drill chuck mostly. Changing ER collets a lot can get tedious as well. Also Rigidity suffers some because of the longer lever. For example my mill has a full size Bridgeport style head and I can not run anything larger than 1/2" in this option. Will be a bit more expensive than just buying a set of R8 collets.

If you don't mind reaching up and changing collets every time you want to change a cutter go with the R8s.

Quick change would be the ultimate in my opinion. I've seen them in action and looks very nice although I can't speak of rigidity as I've never personally used them.
 
I bought an R8 to ER32 collet chuck with ER collets like this one off eBay. Don't remember my seller, I've had no troubles with mine. Lots easier to change collets at the spindle than at the draw bar. I have a set of R8 collets too but haven't used them much. Have Weldon end mill holders that have been used on occasion when there was a clearance issue (smaller nose holding the end mill than the collet chuck). I occasionally use an electronic edge finder that has a 20 mm shank, have a specific 20 mm ER collet for that one too. I have a number of Jacobs chucks with straight shanks (3/8", 1/2" and 5/8") for drilling. Have the multiple shank sizes to avoid changing the ER collet. My set up is in the bottom picture.

Bruce

294859

294860
 
Didn't even think about the straight shank drill chucks. Duh
 
If money is your highest concern the first thing I would do is check the shank size of the end mills you have. Most end mills cone with standard size shanks. Those under 1/4" usually have 1/4" shanks. Those from 17/64 to 3/8' have 3/8" shanks. Those from 25/64 to 1/2" have 1/2" shanks, and so on. If your end mills fall within these parameters you'll need a minimum of collets. You can generally get by with half a dozen or so collets to cover the range of end mills the machine can handle.
As for drill chucks you can use either an R8 shank, or straight shank the size of one of the collets you already use for end mills. Personally I use R8 collets with the standard Bridgeport drawbar. If you're working within the machines parameters they will hold either a drill, end mill, or drill chuck with no problems. I have been using the R8 system on Bridgeports for over 30 years. I've yet to have an end mill, drill, or chuck slip. Then again I don't overload them by taking oversize or over depth cuts. The R8 system is by far the least expensive. It may not be the fastest, or most convenient, but it is certainly adequate.
If speed or convenience is more of an issue you can always invest in a power drawbar, or go to the ER system mentioned by Bruce.

As a side note the company I worked for had 3 full time machine shops and maintenance shops in over 30 production facilities. The full time machine shops used Tree brand milling machines with their own proprietary collet system. All the maintenance shops used Bridgeports with the factory R8 collet systems. In all the time I worked there I don't recall having more than 1 set of collets for each machine regardless of brand. From time to time we did have to purchase specialty collets, but for specialty tooling not because the standard R8 collets were not up to the task.
 
If you have limited budget, and don't already have ER collets, the cheapest option is to stick with R8. Just buy the ones you need for the bulk of the tools you have. That way you can get nicer collets with less runout, which helps with tool life. The sets are handy for odd sizes, but get expensive fast for good quality.

I usually run ER40, but I had already purchased them for the lathe. My Bridgeport came with a small set of R8 that I use with larger endmills or deeper cuts to improve rigidity.

Quick change looks nice, but I don't want to be locked into having a holder for each tool that I have to buy from one manufacturer. For a CNC or production shop, it's probably worth the price. For my hobby, not so much. I'd rather sped that money on cutters and materials. But to each their own. Whatever makes your enjoyment of the hobby improve is worth something.
 
The middle road for convenience and rigidity is probably an ER system. If you already have one for another bit of tooling, use that size; otherwise get an ER 32 or 40 arbor with an R8 shank.

As others have pointed out, you don't need a full set of R8 or a full set of ER. That sort of thing is more helpful in a lathe, where the stock being held can be of odd sizes, but tooling has a few standard shank sizes.

I tend to use ER collets for most milling, and R8 collets or shanks for dedicated tooling: drill chuck, boring bar, and the larger end mills (should probably be in end mill holders but a dedicated collet seems to work).The ER is nice when you're going to be swapping tools out a bit, e.g. a 2-flute for plunging then a 4-flute for widening then a chamfer mill.
 
Start out with the R-8. Make sure you have 1/8-3/4 by 1/8 increments. This will cover 99% of what you will need at the lowest cost. Straight shanks on chucks, boring heads and fly-cutters will reduce the number of collet removals and knee cranking. I use 3/4 shanks if possible and shorten them to about 1-1/2 inches for ease of insertion. Once you figure out your needs, you might go with ER, but you may never need it. Learning to remove and install R-8 tooling with a bump of the power (NO WRENCH!) speeds things considerably. Quick-change tooling is more suitable for production situations. In my job shop, we had 8 vertical mills. All were strictly R-8 tooled, no ERs or quick-change.
 
I would like to know more about this power R8 removal... :)
 
Thanks for the advice guys. I’ve got a run of 10 parts with various holes and threads in them coming up and the thought of changing a tool that many times makes me shudder! But yes I agree, having a dedicated tool holder for each tool will probably make the system too expensive on the mill.

A power draw bar may be on my project list!

I have a small selection of R8 collets so I’ll have a look through the tooling and see what fits what and try use that for the short term before I can invest in different tooling at a later date. I might get an ER32 holder as I have the collets already but I shall have a ponder!

And yes, I’m curious by this power removal too!
 
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