80's Series 1 Bridgeport Table Dovetail and head question

Hey guys,

I bought a 80's Series 1 J head Bridgeport Textron that appears to be mint. The table surface, knee (chrome), column, and saddle (chrome) have all the scrape marks. It doesn't seem to have any scars (drill holes, end mill slots, scratches, etc). Minor paint chips, and has dry oil residue. The owner said that he bought 5 new BP mills and this one got used maybe 20 times since it was purchased.

Table Question:
I've used several BP mills, different vintages and models. On most of them I've noticed that the dovetails on the underside of the table have scrape marks. Some are more noticeable than others, depending on the wear, but they are usually always noticeable at the ends of the table. The 80's BP I bought, doesn't seem to have any at all, and the dovetails appear to be ground. I can not find any scrape marks, even on the ends of the table. Did Bridgeport ever grind these dovetails and not scrape them? I do not believe they are worn, I could be wrong, since there is no visible wear, gouging, scoring, etc.

J head question:
I would like to swap out the step pulley drive to a variable speed 2J (not interested in VFD). Can you fit a 2J variable speed assembly on a J head quill casting/housing?. I looked at the part numbers and compared them, and they all seem to be the same. I've read that the spindle length may vary, aside from this, any other things that do not allow for this swap? I know that I can just buy a complete 2J head and just swap out the heads, but I want to know if its possible to just swap out the drives.

Thanks in advance.

I'll post pictures of the mill soon.

Bore.Stroke.Port said:

J head question:
I would like to swap out the step pulley drive to a variable speed 2J (not interested in VFD). Can you fit a 2J variable speed assembly on a J head quill casting/housing?. I looked at the part numbers and compared them, and they all seem to be the same. I've read that the spindle length may vary, aside from this, any other things that do not allow for this swap? I know that I can just buy a complete 2J head and just swap out the heads, but I want to know if its possible to just swap out the drives.

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The lower part of the heads are the same!

Yes, you can swap a Vari-speed head on to a step pulley lower. Unsure what parts would be interchangeable?

You may want to contact Hi-Quality tool and find out what parts would be needed?

Kevin

Table: Never seen ground ways on a BP unless it was a rebuild. Picture would help

Head. The lower head is the same for J and 2J head assemblies. The same!

How do you know it's "80s vintage"?
When Textron bought BP, one of the first things they did was to drop the J head. Textron owned from 68-85. IIRC, after about 1970, there were no more new J heads. (I've heard with no substantiation that a J head could be special ordered)

This doesn't all add up, ground ways, J head, Textron. Especially the "used 20 times". I'm a skeptic!
JR

Table: Never seen ground ways on a BP unless it was a rebuild.

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Actually, BP ground all the ways on their tables, I've seen the machine that did both sides at once. It was in use the week of the auction, still somewhat clean, wet, and new wheels, extra heads, went for $1,500 IIRC, probably to a scrappy.

I think the question is, "did BP send any out that were not flaked"



smt

stephen thomas said:

I think the question is, "did BP send any out that were not flaked"

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As usual, you are correct. It was the column that was unground. But, as far as I know, everything was flaked.

I have an excuse though. It's hot as hell here. Close to 100 with no air. My brain starts to overheat without an occasional adult beverage.
JR

Thanks for the replies, and answers.

@JR, According to the stamped number on the knee, its a 1980. The spindle speed plate on the step pulley housing says Bridgeport Textron. I thought that the step pulley J head was always a cheaper option given to the customers that wanted to save some money?

I have been around new, reconditioned, and worn BP mills. There are small signs of use/wear that machines display, wear on handles, small dings on the tables, wear on bolt heads/nuts from wrenches, damaged knurling/scratched dials. This machine doesn't have these signs. I know this does not mean that the mill is not worn, but in my experience, its a small detail that tells you how much certain components have been used/treated. Most reconditioned mills I've seen still display some of these signs, since most components are only replaced if they are out of spec, not because of a small cosmetic issue.

Also, the x/y leadscrews have about .014,.016" backlash through the full travel with no apparent tight/loose spot. I know this can be fixed by replacing nut/screw, but I don't think that is the case here.

I'll get pictures posted tomorrow. Again, thanks for the help, and please know that I am not trying to sound like a know it all, just making comments from my experience. Maybe this one went out without the scrape marks.

JRIowa said:

I have an excuse though. It's hot as hell here. Close to 100 with no air. My brain starts to overheat without an occasional adult beverage.
JR

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I'm not sure whether you are bragging, complaining, or just being a whiny butt. If you come back home next week you can welcome another cold front and go from overheated to frozen.

gbent said:

I'm not sure whether you are bragging, complaining, or just being a whiny butt.

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Yes to the above. It's already in the 90s at 10AM. I like than, you never have to scoop Hot! Got not quite 4 weeks before coming back. I'm working on my tan. Please make sure all of the cold weather is gone before I get there.

Gotta run, the bar opens in 10 min.
JR