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Turcite found on new-to-me Bridgeport. Help needed

W

wordsmith07

Aluminum
Joined
Aug 11, 2018
Location
Athens AL
Started this in the Bridgeport Forum but thought this might be a better place for help.
Bought a mill and stripped it down to rebuild head/table/ knee etc.
Found .0030 turcite on the saddle , top and bottom.
All gibs had been run all the way in so my question is:
Should I install thicker turcite since the gibs were maxed out? Will that give me more adjustment ?
Also I see there was a milled out section in the middle of bearing surface.
I guess that make leveling easier?
I have no experience on scraping. The next class in my area is January 2021.
I have a 8" precision level but no long straightedge master.
On the bearing surface for table, one end only of turcite was almost worn through.
Any advice appreciated.View attachment 301246View attachment 301247
 
It sounds as if someone already put Turcite on it and didn't glue it on good, or did you strip it off? The Turcite was on the flats. Was it on the opposite side dovetails and the gibs? You must mean .030" / (thirty thousands)?

If I were you I be a detective and do some testing with some plastic shim stock.Shim Stock, Color Coded Shim Stock: Artus Corp. then start with .030 (old size) .005" for the typical glue thickness. You can cut a shim from the assortment say 1" wide and 3" long. Slide that in to the 4 corners and slide the gib in and see what it looks like. If it was on the opposite side of dovetail. slide in the shims there too. Then if that fits up good with the plastic shims then use that size Turcite. It is .032" , contact Bearing Manufacturer | Bearing Supplier | TriStar Plastics and order Rulon 142 and the glue. They sell it per sq. foot. it will be 12" and you tell them them 24" or at least 1" longer then the ways. You can cut it with sharp scissors I would also cut it 1/4" wider too.....check it out and let us what you find. Or if this sounds confusing call me tomorrow. 651 338 8141. Rich
 
Interesting. When we grind saddles and do turcite, we get down to the recessed depth so that there is good contact between the epoxy, saddle, and turcite. One would think that the gap between saddle and turcite would either dip the turcite and allow crud up in there.

Or was the turcite only on the "way" part and not the recessed part? Installing thicker turcite will (or theoretically should, if they were good with the turcite) throw off your center lines, so you would have to do some modifying on your brackets for the bearings/lead screws. I would view the process as two different steps to get to the right place. Properly turcite the ways for the machine to run properly and then properly shim (you can also turcite the gib if you wanted to) the gib to fit.

+1 to testing for turcite size that Rich described, thats how we do it.

Jon
 
Thanks for reply to you both. Yes, the turcite is 30 thou, (misplaced decimal) and I measured the rough milled area on bearing surface of table. There is approximately 6 inches milled area in the middle of the 18" top of saddle. I measured the depth of milled area with feeler gauge and it was about 7 thou lower than each side. I THINK the milled area adhesion let go first and that's how I saw the turcite below grease/grime and remainder pulled off readily.
Now the bottom of saddle that rides on knee was better adhered.
So you suggest I start with shim stock on bearing surfaces and check gib fit from there? Sounds like a great plan. At least I will have a starting point.
One question, would you still place turcite ( or Rulon) over the milled area or just on higher surfaces?
I have added additional pics of both sides of saddle. No turcite on gibs was found.
Also shim stock on order..
View attachment 301289View attachment 301290View attachment 301291View attachment 301292View attachment 301293
 
You have a real mess, sorry for saying that. It appears whoever did the work was a not qualified or he wanted to make a quick sale. I have to ask, what do you expect to do with the machine when your done? As there is a 1/2 a___ed way of doing this if your only using the machine to do lawn mower repairs or non precision work. If your going to expect precision work that is square in X, Y and Z your going to have to do a lot more work. Just trying to figure out what your expecting. In the old days when Bridgeport's used grease to lube the ways (I know some say they used a grease gun filled with oil. No matter what lube was used...I'm not going to debate that). But back then they milled the center low like your seeing. I suspect the goofed up mechanic (will call him Gum now) he had seen that and milled out the middle. The factory would never milled it like that as they stopped doing that when they went to one shot lube. If gum knew how to bond turcite to iron he would have roughed the surfaces or sand blasted them so the glue would adhere. He just glued it on the old worn way. looks like gum tried to scrape in some pockets in the old iron. Bad News...

Anyway...if you want to just buy some new turcite and bond it on we can do that. But the accuracy will be crap. So what do you want to do? Rich
 
Again, thanks for your attention to this project. I am a retired woodworker that got into blacksmithing a few years ago to be able to produce ironwork accessories for my client's requests. Bought a round column mill for some projects and later wished to upgrade and expand the capabilities of my mill.
I won't be producing products in any quantity and so far have made drilling and routing jigs for installations, welded up motor shafts and turned them down on my lathe etc., and yes made a piece or two for small engines and hit and miss motors.
However, if the cost is not prohibitive, I might want to have the saddle and table milled then scrape them in after a class.
However:
If I can just add turcite, shim the gibs and at least have the accuracy I am used to with the round column mill with its DRO, I might be better off going with that.
On this mill, I rebuilt the vari-drive, motor bearings and completely went through the quill assembly repairing the forward and reverse feed assembly.
I really don't wish to invest more than another 1K in table and saddle because I have yet to take the scraping class coming up that is about 2K.
I enjoy rebuilding old iron, I have redone several Walker Turner drills etc. but might have made a poor investment here.
 
Sound like the easier way is what your after. I was thinking you could cut up,the old turcite in 1" strips about 3" long and use it to check the gibs. mike the old stuff first, then add .005" proper glue thickness under it at the 4 corners and try to slide the gibs in and if they are sticking in to far slide in thicker shim. Do that and lets see what happens. Buy some extra glue and fill in the enter gap. We can help you scrape the rulon 142, it's easy as scraping butter on toast. :-)
 
Okay, got the knee mounted today and placed the saddle on it with .030 shims. The gib is sticking out about 5/8". Sliding frontward it "binds at about 1" from edge of knee. Sliding to the rear, it binds about 4" from rear. This is just hand sliding but I think to "crank" it further each way would wear the feed nuts rapidly. I have no precision straight edge so using a piece of glass- it appears there is a 6 to 7 thou "sag" in middle of the knee.
So there is about 8" of moderate travel without binding.Maybe some moderate scraping could improve this.View attachment 301458View attachment 301459View attachment 301460
 
Rich,
I wondered that myself until I remembered the outermost ends (front and back) of the turcite were worn a good deal thinner on ends. I guess operator kept tightening gibs to compensate for turcite wear.
I'm going to recheck all measurements tomorrow after yet another cleaning of knee and saddle. Added heavier way oil today, might use WD40 tomorrow to lessen whatever that might have affected.
BTW the shim stock is "precision" brand. Googled the company you suggested but Zoro sent this. Miked it and it hit right on .030.
Thx again.
 
Have a depth mike? Mike down from the clearance surface above the dovetail. It is no doubt worn in the center and high on the ends. If you want to make it better you will have scrape it . I believe there is a rebuilder in Alabama who could do it. I will email a friend who used them.
 
View attachment 301575

I thought of that but the top of the dovetail has a low section of a few thou for about 6 inches similar to milled out area on saddle. Funny though, it doesn't have milling marks like the other. Slick on both areas but low enough to hand a fingernail and straight like milled out in past. Please do check with your friend. Probably not cheap having to set up the knee on another piece of equipment.
I think I highlighted the area with a magic marker line, hope it shows in photo

Thx
Joe
 
All Bridgeport's of old had that low spot. I think the did that so when they machined the back of the knee it sat on 4 outside sections and no chance it was high in the middle. I'll email him now and see what he says and will cut and paste it here.
 
I got an email back from my friend Lance, I was wrong of the state, sorry:

"The folks I used were in South Carolina. Here is their contact info:
I dealt directly with Jody!"


Machinery Solutions, inc.
Lexington SC

Jody Stevens
Service Technician
[email protected]
803-359-7000, ext. #107
 
This seems to be a large all service machine shop. $775 to mill top of knee. About $1400 more to do both sides of saddle and add turcite...
 
Richard,
Called the plastics place and they should be e-mailing quote. Is there an etched rear surface of will I need to prep the rear for adhesion?
The .030 shims worked well on the table too and gib looked good.
I have the mill humming with new rebuild of head . Vari-drive quiet and smooth.
 
Yes....when you look at the material...one side is a bright smooth aqua colored side.... the opposite side is a dark, almost black, that side is acid etched and that is the side you bond. Be careful not to use to much epoxy as their epoxy has .003" glass beads in it to get a thin layer. The instructions say to use denatured alcohol but I use brake cleaner in a spray can. The cleaner that gets cold when you spray it. Be sure to mark the oil holes in the saddle. I also take a butane torch and heat up the oily old cast iron to sweat out the oil in the porous top layer. Be careful not to get it to hot and put the brake cleaner away. Then spray some wax release agent on the opposite side of what you will set it on so it doesn't stick to it. Some set it on a surface plate, newspaper or wax paper also works on flat surfaces. I am careful and assemble the saddle on the table and knee and let it dry on each other. But you have to be super careful. You may want to do it one at a time. It will take 3 days. glue it, disassemble and clean it...do it a again, etc.
 
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