Gunsmithing Buying a bridgeport questions

[jacq220]

I have three differant machines that i will be looking at next week.... all of them mid 80's machines, all for a pretty good price and include some tooling... when i am looking at these, what should i be paying specific attention to? what should i look for that would make it a definate no go... this will be for drilling and tapping, facing the end of shotgun barrels, fluting, cutting dovetails cocking serreations ect.

 

[68GT]

Re: Buying a bridgeport questions

check if it is single phase or three (if you do not have three phase), spindle runout/bearing condition, is the table flat, condition of the screws, condition of the table gibs, does the DRO track accurately (if equipped). Take a mic and a magnetic base for checking.

 

[jacq220]

Re: Buying a bridgeport questions

dont have the measureing tools... the one i am looking the most heavily at is a 3 phase w/ a frequency converter, adjustable speed on the head of the mill (can be adjusted while running) 220 volt, 9x42 r8 spindle. comes w/ collets the converter, some end and ball milles and a 360 machinist vise.... havent seen it yet, but i will this saturday guys says its in decent shape but has some cosmetic blemishes. early 80's late 70's machine... all for under 2k delivered to my shop.... great deal right? well its only a good deal if the machine is decent for what i want to do...
what do i look for w/ condition of the screws table gibs? whats a table gib? it does have DRO, and the guy says it works fine... how do i tell if its tracking accuratly?

 

[ccmind]

Re: Buying a bridgeport questions

2k doesn't seem like a bad price. You might check the quill for slop. Thats the part that comes down when you use it like a drill press. Make sure it's unlocked and see if it has any slop.
Also you can check the backlash of the table screws by turning them one way until the table starts to move. Then turn it the other way until the table moves and keep track of how far you turn the handle before movement of the table. All mills with acme threads are going to have some backlash but less is better. That can be taken out by adjusting the nut under the table as well. Lastly I would look at the dovetail wear. Some Bridgeports have chrome ways and don't get much wear. Others will usually be worn in the middle of the table travel and tight on each end. If you run the table all the way from one side to the other and it seems tighter on the ends you may have some wear in the middle. This can't really be adjusted out unless you remove the table and hand scrape the ways. One more thing. If you can run it under power listen to the spindle bearings after it warms up. You don't want them to be too loud. Good luck with your purchase

Jason

 

[jacq220]

Re: Buying a bridgeport questions

if the quil has slop, or there is some of the wear that you are talking about, is it not worth the 2k w/ tooling? its actually 1650, but i am going to parkerize a few of his guns for him as a part of the deal.

 

[bwanajcj]

Re: Buying a bridgeport questions

Make sure they are not set up for some bizarre, outdated, or propriety collet system. A good deal can come back and bite you in the pocket book if you need to retool or buy holders for new tools.

 

[jacq220]

Re: Buying a bridgeport questions

its set up for R8

 

[ccmind]

Re: Buying a bridgeport questions

Most of the things that have wear can either be adjusted out or worked around. I think the price is decent. People build some pretty cool stuff with less than new Brigeports.

Jason

 

[Kasumi]

Re: Buying a bridgeport questions

First impression is it sounds like a good deal, delivery alone can run $400-1000 for riggers to move it. My XY Acu-Rite Digital Read out cost $1925, swivel base vise run $390. I'm running a 1960's Bridgeport and it holds .001 no problem. To check if it tracks buy a good Dial Indicator from MSC, they only cost $125. Bridgeports are hard to kill. Good luck

 

[Decoy]

Re: Buying a bridgeport questions

Another thing you might want to verify is that all the adjustments are free and working. Loosen and adjust the four bolt that swivel the entire upper assembly left and right along with the bolts that move the upper assembly in and out. As for the head adjustment to indicate the head it it will b; the four head bolts that adjust the angular adjustment left and right and the angular adjustment back and forth.

Sometimes if not cared for these can freeze up and cause some issues. I would just use an indicator and ensure that you can indicate the head to zero with these adjustments after making sure they all move.

If you can't get it indicated or there is alot of movemtent it might be a case of bad spindle bearing, not the end of the world though.

Good luck and it sounds like a reasonable deal.

 

[Tylermtech]

Re: Buying a bridgeport questions

i would think the phase converter is worth near a grand alone.

 

[jimmyrjessie]

Re: Buying a bridgeport questions

you can buy a rotary phase converter for 500 to 700 shipped and have enough hp to run the mill and a lathe at the same time. but to answer your ? grab the table on one side and push and pull on it if it moves much that is a good sign it has alot if use. now having said that you can adjust the gibbs and remove some of this slop. but some times the wear in the center portion of the ways is just to much to adjust out without making it so tight at the outer limts in y that you can barley crank it all the way to those limts. that would be a very costly repair also as some one else stated the slop on the x and y screws is something to watch for. altough can be compensated(sp) for by keeping your back lash in the same direction at all times.