Bridgeport saddle x axis central relief- step down reference

Hey everyone happy new year,

So I just finished scraping in the saddle of a new to me Bridgeport series 1 9x42. I haven't even used it but decided to do it right and renew the thing since it was full of grease and had been worn pretty good. Anyway. I started with finding a good reference, which turned out to be the x axis in the middle where all Bridgeport that I know of, have an area about 5 or 6 inches long that's scraped but sits lower than the outside 2 sections of each way. I scraped the y axis first then went to the ax axis. The left front gib side way outermost corner had the most wear and I made this my zero datum. I took about .0065 off the rest to scrape true to the y axis. Doing this made me cut into the reference I used in the middle of the X axis. Thinking more about it, I'd like to have your opinions on this area. My thoughts are that they relieved this area for 2 reasons, possibly 3. (1) The first and main reason is to eliminate a central rocking point once wear begins to develope. (2) to use as a reference for future measurements. (3) for lubrication to hang around along with swarf (ahhh).. Anyway.. I feel like I should make this area shorter in length, on the gib side at least, to increase surface area to in part reduce wear on that tiny little bit of way that's left over and always wears down first. I almost feel like it needs to be there to remove any sort of rocking that could occur with a high point, although the gibs should be tight enough to eliminate this I would think.. do I even need to do this? I know my scraping is on point so I have full contact across the entire surfaces. Any help would be appreciated. Thanks everyone have a happy, safe, and successful new year!
Here's a picture to show the area I'm talking about. It's just freehand sharpied.

https://ibb.co/ggsBV2q

I see your machine is one of the old machines that uses Zerk fittings. Do you have a granite or scraped surface plate to set the saddle on? How was the Y axis ways? You are right about relieving the middle so it won't rock. The older Bridgeport's didn't put way wipers on the table ways and that's where all the junk collects on the bottom of the table and wears first. Plus as I was taught by one of the PM old timers Professor Archie Cheba the table bends convex because the T slots get peened or stretch when the vises are tightened to much causing the wear to be on those extreme outside edges. I would set the saddle on a surface plate and scrape both sides flat to it co the ways are Co-Planer, then set the saddle on the back side and scrape the back dovetail with an angled SE. Dennis Foster has a nice one he makes and he has a good thread on here.

The table is bent high in the middle and if your going to do a decent rebuild I would sent the table out to have it ground top, bottom and dovetails. You also peen the bottom of the table to straighten the table. Many rebuilders run a T slot cutter down the T-slots to release the tension in the peened top before grinding, milling or scraping the table. Those old Zerk machines center clearance was .030". I need to do some research as I believe they did that to use grease and the grease made a seal to keep out the swarf. I know many say to use way oil in a grease gun. I have told customers to do that after I made the openings smaller or replaced the Zerks with a Bijur one shot system. Lubrication System Installation and Information - H & W Machine Repair or K1099 - Zerk to One Shot Lube System for Bridgeport Series I Mill - H & W Machine Repair

Thanks for the insight Richard. I've actually already used a surface plate and scraped in the saddle both x and y flats, using the scraped in lower area on the x axis as my reference as it was the best datum I could find for a repeatable reference for measuring the y axis. I just set it on some very nice 123 blocks on my surface plate, took some measurements, then scraped in the y axis. This thing was covered in grease, what a mess, never a big fan of grease. I know Bridgeport did some studies and determined way oil to be the better alternative later on down the road. Anyway, the y axis ways weren't extremely bad, they had at most .003 variation. The gib side of the y axis flats had zeros on all 4 corners of the ends. The opposing side had zeros on both corners of the one end, but 1.8 thou on the opposite end. The non gib side I removed the most material in the middle and that was .003. the gib side I removed 1.8 thou. Once I got a nice pattern I did the x axis and had to remove a total of .006 since the gib side smaller section was worn that much on the outer corners. As far as wipers this did have wipers on it actually. And that's funny you mentioned Dennis as I literally am getting one of his 36" featherweights in the mail hopefully tomorrow. I would like a slightly smaller angled straight edge as well though. I have some well seasoned cast iron I could use to make my own but we will see. So you think I should drop that center section down around .030? I really would like to try making that relief maybe only around 3 inches long on the gib side but I'm not too sure on that. My intensions are to make for a more uniform wear throughout it's use. I haven't checked the table yet for any distortion but I will try and get to that shortly and see. It's nice to get your input and I enjoy reading through your posts as I've gained alot of knowledge from them.

Regards,
Sean

I tell my students to scrape the center 40% of the short side blue or high spots down first until they don't blue up and then blind scrape it down .002" to .005" low. If you relieve it to much the oil will spill out. You sound like your pretty experienced, so have at it.

PS: On some machines you can't lower the 40% as the slide travel is longer. one has to measure it, but on a Bridgeport follow the original...some say 30%, but I say 40%.

Thanks for the input, I've scraped in a few other machines but this is the first Bridgeport. Hopefully all goes well.