Proper size Tee nuts for 9x49 Bridgeport

B

Billy Dixon

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Greetings, this is my first post and I'm sure you'll pick up I'm a newb to the wonderful world of machining. I'm the proud owner of a 9x49 2j2 Bridgeport and in the process of getting it up and going. I'm a little perplexed about the proper size tee nuts for this mill. The slots in the ways measure 5/8'' and a 5/8" bolt fits snug. What is the proper size? 9/16" or 1/2"? Thanks in advance for any help. More new guy questions to follow I'm sure.

BD
 
I really enjoy using the t-nuts I made myself, for all of my machines, rotary table, etc. I can make them so they fit better than anything I have purchased, and they just seem to slide in the t-slots better. Distort the bottom thread, or do not tap quite all the way through, so you do not run studs and bolts down into the bottom of the t-slots, which can cause damage.
 
You don't really need to buy a couple. Looking at a photo in a catalogue or online will give you the design and approximate sizes needed. The thing to watch out for with t-nuts is that they are not made too tall. They will pull up to the shoulders when tightened, and the top can then protrude above the table if you are not careful. Then it never tightens to the table. It is good to finish them even a bit lower than that, so accumulated swarf is less of an issue. Yours will not be hardened, but unless you are using them full time, that is not much of an issue. They also might be a little less strong than the hardened ones, but they do not need to be tightened that hard anyway, or you will risk damaging the table.
 
Thanks for the tips. I ordered a couple to get my vise tied down, after that I'll make my own. I'll be sure and check the height. Never thought about causing damage by protruding too far, great advice!
 
For mill vises, I've seen machinists use bronze bolts and nuts with the T slot nuts.
 
Billy Dixon said:
Thanks Bob,
That's what I was leaning toward, just wasn't sure. Going to buy a couple and make my own after that. Gotta start somewhere!

BD
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Congrats Billy!

I just sold my beloved Hardinge with a Rusnok head and found myself a Bridgeport as well.
One common issue with many milling machine tables is the distortion of the table and T slots from people cranking on mounting bolts over the years. You may just need to run a file inside the slot, not deep down where the top of the "T", obviously the T slot is an upside down "T". You need to run the file against the 5/8 inch surfaces, flat against those surfaces. This will take burrs, distortions, and any other imperfections caused over the years of hard work and smooth them out and make the T-nuts slide through much more freely.





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Bernie
 
Thanks Bernie, I'll check that out. My Bridgeport is a vintage 1977 complete with a Bausch and Lomb DRO. Pretty snazzy technology for 40 years ago. Got my first digital watch about the same year. I'm forth owner. First was a One man machine shop. Second owner was also a machine shop where it sat in storage for several years before the 3rd owner bought it at auction I bought it from him because he has access to a mill at work and it opened up a 3rd slot in a nice garage. The third owner had cleaned on it some and I spent the better part of 2 weeks scrubbing on it. looked like a couple gallons of 30 wt. and a lot of dust. Its finally operational, sounds better that the machines I got to run at the college where I got a semester working on a similar Bridgeport. I bit the bullet and bought a Kurt vise, it sure looks pretty sitting on it, and I am working on a DRO rack.

Thanks to all for the tips and tricks, looking forward to learning more.
 
Be advised that the table slots can accumulate a thickness of grime that can prevent standard 5/8in t-nuts from sliding the length of the slots sometimes.

Just needs a good cleaning/brushing/scraping to clear them.
 
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