J-Head quick change???

[averagef250]

I'm looking at purchasing a J head bridgeport mill that lacks a head. The mill will be CNC upfitted for hobby and semi-production use. I will need to buy a J-head for the mill and thinking ahead, having the ability to change tooling very quickly is going to be important as well as being able to find CNC specific tooling at reasonable prices like tension-compression tapholders and such. R8 toolholders are inexpensive, but tool changes seam like they'd take too long with a draw bar. I've read bits and pieces about special 30 taper, Erikson and quick-switch 200 spindles that can be had for a bridgeport mill, but I can't find much info on them or any sources for these spindles. I've also looked at a company offering asian made replacement J-heads with a cat40 taper, but they come with a 5hp motor and varispeed unit that I don't want. Anybody dealt with this before or have any suggestions for what I should do? Thanks.
Dustin

[Doug_C]

This is what we use in R8 applications. It is a bit spendy for a set, but compared to a spindle conversion they are very nice for rapid tool changes below 3/4" endmills and drill chucks.

Having multiple holders and chucks adds to the cost, but the payoff is compounded over the long haul. A twist of the collar removes the holders and they just snap in place on returning them to the body. These are great for standard 2-3hp CNC and manual mills under reasonable chip loads.

I still remove the body for shell or fly cutting and boring head operation. Proper job planning can reduce this change over in production. Perfect for low hassle Tool making, R&D or prototype work.

Royal Products Easy Change system

DC

[MikeC]

That's a good looking setup and it sure beats the expense and effort of changing over to a Kwik Switch 200 spindle. My bridge mill has a 300 taper in the spindle, so I have been looking at stuff on Ebay for it.... once it is up and running. That stuff is expensive and in demand. Even used, it is steep.

The bridge mill came with a Collis 300 series ER-40 collet chuck, so I'm going to just buy a decent set of those, which will cover all sizes from 1/8-1". It'll be lots cheaper than buying the 300 holders. I will have to buy shell mill arbors, but the ER-40 is a tough collet. You may want to check into one of the ER collet chucks for R-8. I have seen an import set on Ebay for about $200.

[Doug_C]

We have a few of those collet setups. Due to either over torque, slipping or some other unexplainable condition. I have found some of the collets will not hold anything on the spindle axis. Rotate the collet a bit and it seats in another direction. I am sure it is some sort of distortion to the collets because not all of them do this in the same holder.

Not to mention the need for a wrench to remove/replace the cutter and/or collet continuously. Not well suited for CNC tool length offset repeatability. Even the air draw bar style do not repeat all that well.

I am not sure of this style. It is R8 with a rather smallish retention knob stud.

Mach1 system

DC

[artk]

I have a Bridgeport Series 1 with a 2J head. I use a power drawbar, essentially an air impact wrench dedicated to the R8 spindle. Another good feature is that it doesn't take away any vertical working space from your mill. At the press of a button I change tools in seconds. I love it!

Regards,
-Art K

[sandman2234]

I was thinking a power drawbar would be the way to go also...
David from jax

(and glad I am not having to TRY find a reasonably priced J head for sale)
David