2J vs J Bridgeport milling head for beginner.

[JamesBondo]

I have a question regarding Bridgeport milling heads and am wondering if someone can give me their two cents. Is there any reason a J head with the multi pully speed adjustments would be better suited for a beginner than a 2J head with the single variable pully? In the event of a crash, is one more ideal than the other for allowing the belt to slip rather than something else breaking?

 

[RoninB4]

Multi pulley design is simpler, easier/cheaper to repair, and less likely to need repairs than the variable speed head. I've been a machinist for decades and used both for many years. On the job, the vari-speed is faster and more convenient to change speeds but can also be susceptible to problems/repairs, especially if it's an old used mill with an unknown history. New works fine, like anything else new. Used machinery history is an unknown. When I bought a BP for my home shop I only looked for a multi pulley type head.

Changing speeds with the multi pulley design isn't that slow or difficult so it's a non-issue to me. There's a technique to changing belt/pulley so you don't get your fingers caught/pinched so go slowly until you learn it. All machinery have techniques particular to that machine so consider it part of the learning process.

Also, changing from low to high speed you MUST ensure that the gears have meshed or you'll get an awful grinding noise when you start it. That grinding noise is the gears being ruined and it happens a lot to those in too big of a hurry. To me, it's easier to verify that the gears have meshed properly with a multi pulley head because you can use the pulley (do not grab the belt) to rotate the spindle back/forward to engage the gears. With a vari-speed you must grab the spindle down by the cutter to rotate. Not always a good choice. Same thing applies when using an indicator in the spindle to tram or locate a hole, better to rotate at the head than at the spindle mouth. JMO so YMMV

 

[MushCreek]

I prefer the old step pulley for a home shop. It's much simpler, and they work just fine. Millions of them were in use before the 2J came out.

I worked in a shop that had six 2J B'Ports. They sent a head out to be rebuilt. When it came back, it rattled like crazy. It sounded like a diesel engine. We were told "They all do that." (They don't). They also said that it would quiet down after we used it for a while (It didn't). Since the company had nearly unlimited funds, they just traded it and three other machines in and bought brand new ones. No, they didn't sound like a diesel.

With a repair budget of basically zero, I intentionally looked for and bought a step pulley B'Port for my home shop.

 

[alexb2000]

I have a 2J and a couple of older J heads. I don't think either will matter for a beginner, I would buy the mill that was in better shape overall regardless of head type.

I read all the 2J war stories the Internet is famous for and at least for me it is way overstated. The 2J head is simpler than a golf cart clutch to repair, but yes there is some potential cost in there if you have some major problems to correct. Of course those are clear when you run the mill. Other than the speed control the rest of the head is the same so there could be problems with either one.

 

[Zebu Fellenz]

I've used both and have a step pulley machine in the shop now. Variable speed is a little nicer to use and all else being equal I'd prefer to have it.

 

[jmarkwolf]

You're probably going to need the means to make 3-phase for any B'port you buy.

I would recommend buying the J-head for reasons cited above, then use a VFD to "make" your 3-phase power, and the VFD can vary the spindle speed with the twist of a knob.

 

[Grant Gunderson]

The J head has less to go wrong with it and is cheaper. I’m running mine off of a VFD and leave the belt in the middle pulley configuration and adjust speed via a pot on the VFD. That works great 90% of the time. I only change speed bus the belts if I’m using very large or very small cutters.

 

[zmotorsports]

I prefer the variable speed for my home shop. But I'm not a machinist.

 

[iajonesy]

I too worked in a machine shop for 40 years and we had both machines. We never had any issues with either. If I had the money, I'd buy the VS just for convenience sake and also resale value. You can't go wrong either way.

Mike

 

[matt_i]

I don't think its a big issue either way.

On my M-head machine (yep an oldie!) with step pulley I rarely changed the speeds.

On 2J-head machines home and work the only times I mess with the vari speed is

1) using edge finder to get to 1000-1100 rpms per Hermann Schmidt
2) using the back gear and 60rpm is too slow

If I'm going to run direct drive I run at 500 rpms. In my world I'm fixed on not burning up the HSS edge tools. If you have a machining center and are trying to pump out parts then by all means the 7500+ rpm spindle & solid carbide edge tools are par for the course.

My home machine is starting to make noise and its on a back burner to fix one of these days. It works just fine just slightly irritating. Any type of spline-driven quill machine is eventually going to have issues in the wear at that interface.

tl;dr, I wouldn't stress about either choice. Good idea to run the machine before you get it home.

Edit: if you can buy a machine with a working readout system (DRO) that's the most useful & time-saving accessory you can equip the machine with, imo, which also assists in negating wear in the machine itself when it comes to positioning the table.

 

[dutchgray]

I have a 2J, but it was on top of the best machine I had seen come up within a reasonable distance in almost a year of looking, either is fine. Its not like you can't get the parts to rebuild them like with less common machines.
Buy the least worn example you can find for your budget and the more tooling you can get with it the better, you will never get tooling cheaper than what you buy with the mill.

 

[rsanter]

Nothing wrong with either of them if they are good.
The key issue is the often the 2j varidrive head was not serviced or taken care of as it was specificed to maintain. When they fail it is an expensive repair, more expensive than just service/repair of a step pulley model.
Use to me that the 2j models were worth more as people wanted the ease of the variable speed. Now with the advent of economical VFDs, there is no real advantage to the variable drive head

 

[JamesBondo]

Thanks for the info. Knowing that, I feel pretty good about going for either type, assuming good condition. I do like the idea of the J head with VFD like jmarkwolf and several others suggested.