bridgeport question

greets all i have a bridgeport Jhead (varispeed pulley) not sure of its age.
i bought it recently and have been 'fixn it up'
at any rate.. the table has alot of slop in it. if i push/pull the ends of the table it'll move maybe +/- 5degrees. a heck of alot.
i can't adjust the dovetails any tighter. i removed the adjustment screw and pushed the dovetail key (?) in. it went down about 1/2" past where the screw bottoms out.
it is reasonable to assume that these "dovetail keys" are worn.. and not the ways? if so, anyone know where i can order a new (or barely used) set?
(the X, or short axis, is shot.. the Y is still good, but might as well change them both)
maybe this is a good time to change the brass nut, too? it seems pretty tight.. i have little backlash.. but its also at the bottom end of its adjustment range.
thanks, -tony
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I slid in a strip of .010" brass shim next to the gib. Not perfect but OK.

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My old BP had had its ways rescraped and new X and Y nuts. The X axis gib as it came from the rebuilder has Turcite on it. If it isn't Turcite, it's something very like it. It's white and waxy looking.
A new tapered gib will need to be scraped in and it costs big bucks or is a giant hassle. I like the idea of removing it and putting in a shim. If there's a machinery rebuilder in your area I'd go talk to their service manager. It was great when Hallidie Equipment was a BP official service center - they worked on tons of them and had a "boneyard" they'd let guys like us pick through for free, and had great advice. Now not only are they no longer a Bridgeport service center, they went all the way out of business.
FWIW, to have them scrape my ways and replace the nuts and grind the table and clean and repaint the mill in 1997 was about $1400.
Grant Erwin Kirkland, Washington
tony wrote:

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just got off the phone with a Mr. John Hernandez of Hardige-Bridgeport. He gave me the same bad news: the new gib will have to be scraped in.
the only thing i've ever scraped is my knee.
seems like a shim is my only way out.
wonder how long a shim will last / how often i'll have to change it.
at any rate.. my problem now is finding some shim stock. brass sounds like a good idea. but i'm living up in the remote italian hilltops with very little access to anything useful (like shimstock).
getting a bridgeport mill up here is another story unto itself.
is copper too hard? i can get 0.6mm copper sheeting (they use it for roofing in these parts). would hate to do (further) damage to the ways.
-tony
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Tony,
Almost any material of a constant thickness will do. You just have to put it on the BACKSIDE of the existing gib, not the front face, or working side.
Vince
tony wrote:

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The shim will last forever, there's nothing to wear it out. I used brass because I have a load of it. On other machines I have super-glued paper onto gibs. Be creative, you can't damage anything.

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tony wrote in message ...

Here is dating a Bridgeport info from an old post on this group Michael no xx's in address
From: Peter Reilley ( snipped-for-privacy@mv.com) Subject: Bridgeport Milling serial number list Newsgroups: rec.crafts.metalworking View: Complete Thread (5 articles) | Original Format Date: 1997/12/14
Here is the list of serial numbers for Bridgeport J head milling machines. This is straight from Bridgeport.
Also, I am looking for a Bridgeport class machine that is in reasonably good shape. A DRO would be nice as would a CNC attachment. The machine should be not too far from New Hampshire.
I would be willing to maintain similar lists for other machinery if people can supply the info. You can fax it to me if necessary. email me for my fax number.
This list was scanned in to my computer using OCR software so there might be some errors.
Pete.
BRIDGEPORT MILLING MACHINE "J" HEAD SERIAL NUMBERS
The serial number is on the knee of the machine. It can be obscured by the chip shield.
1938 BH-1 THRU BH-39 Round ram 1939 BH-40 THRU BH-252 1940 BH-253 THRU BH-656 1941 BH-657 THRU BH-1549 1942 BH-560 THRU BH-2943 1943 BH-944 THRU BH-4105 1944 BH-4106 THRU BH-4997 1945 BH-4998 THRU BH-5930 1946 BH-5931 THRU BH-7235 1947 BH-7236 THRU BH-8814 1948 BH-8815 THRU BH-10381 1949 BH-10382 THRU BH-11378 1950 BH-11379 THRU BH-12750 1951 BH-12751 THRU BH-14489 1952 BH-14490 THRU BH-16700 1953 BH-16701 THRU BH-19367 1954 BH-19368 THRU BH-22732 1955 BH-22733 THRU BH-26962 1956 BR-26963 THRU BR-31618 Start of V ram 1957 BR-31619 THRU BR-37278 1958 BR-37279 THRU BR-42110 1959 BR-42111 THRU BR-46938 1960 BR-46939 THRU BR-52598 1961 BR-52599 THRU BR-58552 1962 BR-58553 THRU BR-64987 1963 BR-64988 THRU BR-71981 1964 BR-71982 THRU BR-79538 1965 BR-75939 THRU BR-88180 1966 BR-88181 THRU BR-98089 1967 BR-98090 THRU BR-108351 1968 BR-108352 THRU BR-118640 1969 BR-118641 THRU BR-131778 1970 BR-131779 THRU BR-138139 1971 BR-138640 THRU BR-143350 1972 BR-143351 THRU BR-149294 1973 BR-149295 THRU BR-157909 1974 BR-157910 THRU BR-167652 1975 BR-167653 THRU BR-174083 1976 BR-174084 THRU BR-180697 1977 BR-180698 THRU BR-188559 1978 BR-188560 THRU BR-196987 1979 BR-196988 THRU BR-206296 1980 BR-206297 THRU BR-216473 1981 BR-216474 THRU BR-227523 1982 BR-227524 THRU BR-231700 1983 BR-231701 THRU BR-235985 1984 BR-235986 THRU BR-241350 1985 BR-241351 THRU BR-245659 1986 BR-246660 THRU BR-248551 1987 BR-248552 THRU BR-250531 1988 BR-250532 THRU BR-252874 1989 BR-252875 THRU BR-255463 1990 BR-255464 THRU BR-257888 1991 BR-257889 THRU BR-259897 1992 BR-257898 THRU BR-262188 1993 BR-262189 THRU BP-264586 1994 BR-264587 THRU BR-267635 1995 BR-267636 THRU
----------------------------------------------------------------------------
--




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This file has been around for a long time. Since it goes back to 1938, it applies to ALL Bridgeport milling machines, not just J head. But, the serial numbers from 1940 to 1943 are scrambled. It seems impossible that they sold SN 656 in 1940, but didn't get SN 560 sold until 1942. I have a round-ram machine, SN 1399, which could have been made in 1941, 1942 or 1943!
Looking closer, it seems that 1943 should be 2944-4105, and 1942 might be 1560-2943, as there could be 11 machines that were overlapped in the production line between 1941 and 1942.
Jon
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i, too, have seen this file before. though it hasn't been of much help: the serial number stamped on the knee (under the two chip guards) reads: J-013 thats it. the metal is in pretty good shape.. i'm pretty sure no other numbers were worn off. its clearly stamped J-013.
at first i wondered if i'd gotten bridgeport's 13th mill!
JohnHernandez, mentioned above, dated my machine at/around 1949.
*shrug* -tony
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Bridgeport did make special mills for people, mostly the government. I believe that they had different serial numbers. Is your mill normal for the year that you think that it is. J head vs. M head and round ram vs. V ram? Is the table size normal? I don't know all the variations that they produced.
Pete.
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tony wrote:

It is very possible, that around 1955-1956, when the J head was introduced, and then mounted with the dovetail ram, that a short run of demo or test machines were made to find all the kinks that real shop use will always turn up. That could explain an out-of- sequence number like that.
Does your machine have a dovetail ram? The first J-head machines were built with the round ram, as they converted over to the modern design a step at a time. Does it have 9 or 12" of Y travel?
Jon
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my machine, if i remember correctly, is 9"x42" table.. i'd have to measure in the shop.
has a dovetail ram.
the head, however, has a large nameplate on the side reading "Adcock-Shippley" (again, i may be mistaken on the correct spelling, i'll check it again)
i've been told that the head was added later, but the short serial number on the knee always baffled me.
-tony
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There were some typos in the list. I actually scanned it and used OCR to get the text. It is pretty easy to see the error. In 1942 the 560 should be 1550. The "1" got dropped and the 5 was read as a 6. In 1943 the leading 2 was dropped from 944.
I think that there are some other errors in the list. People have pointed them out to me over the years. I believe that I posted a corrected list a while back.
Pete.
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tony wrote:

Note that the nuts are Bronze, not brass - big difference! On the older machines, they are solid. On the newer machines, they are either partially split into two, or are cut completely into two rings. The arrangement of screws that hold them in the bore in the yoke allows them to be squeezed together to take up backlash. When you do this, you need to adjust it until backlash nears zero on the outermost ranges of travel, where the screw is least worn. These nuts are so hard that the wear in the screw is about the same as the wear in the nut! So, if you have a lot of backlash, 30 - 50% is in the screw, and you won't be able to completely eliminate all of it. Typically, the Y screw and nut are worn much worse than the X, since the oil flow gets to the X first, and only what drips off the X nut gets to the Y.
Jon
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