SCRAPING A MACHINE AND DOING TURCITE REPAIR or REPLACING IT ?

Hello everyone, Most know I am a Machine Rebuilder and teach rebuilding / scraping seminars. I have a reader who emailed me and wants to know about scraping a machine that now has Turcite on it. I asked him to ask his question on the forum so all can see. I had another thread but it got off topic and I want to start a new one again. Hopefully he will ask his question today or tonight.
Any of you others who have questions please ask as this board has several qualified machine repairmen and Rebuilders who can who can help answer questions. Richard King

I wonder if they would create a new forum for "Machine Rebuilding/Scraping"

Here is the question Richard reffered to:

I am rebuilding an FP3NC tool room milling machine. As a point of reference this machine is in my home shop. Main vertical casting of the machine which carries the "Z" axis has box ways.
Sliding on the box ways is a vertical slide (sort of kike a conventional BP knee) It carries the ways for the table ("X" axis).
The "X" axis is a "T" slotted table ,but mounted vertically , that is to say the face of the table is parallel with the "Z" axis.


Here is the general arrangement, with the machine shown running using the horizontal spindle.....
OK now for the problem/question:
I am working on the vertical slide ways where the "table" ("X") fits up.


This photo shows the vertical slide sitting on the main machine vertical casting box ways. The base has been removed and the casting laid down for fitting.
The area in question is the Turcite surface laying horizontal in the photo. Its the surface with the circular oil feed grooving in its face.
When the machine is assembled, this Turcite will be vertical. Its role is to support the bottom face of the "X" table from twisting in toward the machine. It counteracts
the weight of the table and work and provides a way for the "X" axis to move against.
Also seen is the tapered dovetail above the Turcite that provides the gib adjustment.




Another angle of the Turcite. Here you can also see the scraped iron way at 90* to the Turcite...This way supports the bottom surface of the "X" slide and takes the weight of the table and work, and is directly
opposite the tapered dovetail gib....

Here is the problem......



There is an area at the lower edge of one of the oil holding grooves where the Turcite has come off. In the assembled machine this gap will be facing down and will cause the oil in the groove to be able to
leak out...my fear is that this will rob the slide of proper lube.

Additional info:
The "X" axis ways and their mating surfaces on the vertical slide have already been re scraped. Done by a local machine rebuilder who i have used before and who's work is of good quality.
The piece of Turcite came out after i got the parts back form the scraper...so this is not an oversight on his part.
Point is that the remaining Turcite surface blues in fine with the "X" axis ways.

Question is should i attempt to jsut spot repair the missing area with additional Turcite (or something else?)
Or should i bite the bullet and replace the entire Turcite piece and rescrape...
Or, would it be feasible to remove almost all the original Turcite leaving several small islands at each end, and fill with Moglice using the original Turcite as a jig ?

I am interested in any ideas or suggestions here......
Cheers Ross

I dunno but that is sure one cool looking machine :-).

Bill

Could you just fill it with epoxy, it is a small area and all you really want is to contain the oil.??? Regards, Mike

Can't you just use the moglice to fill in that gap? I know the cost is prohibitive for such a small area, but maybe the time required to rescrape the whole surface would offset it? Or maybe that isn't even an option....

If the old Turcite is good,

...(I'm not a Machine Rebuilder but for such a small area)... I might consider removing the loose turcite in that area, gluing (using the right product... epoxy?) a new piece of turcite slightly thicker. Then, with a reference flat and blueing, carefully scrape it until it matches the existing turcite.

Steve

Mike:
I considered using epoxy just to fill the gap. Not sure if it would have any effect on the sliding action...different friction/hardness....would love to hear from one of the professionals on this approach....

Roy:
Moglice in the local area might be a good option. Would need to get a good bond , wouldn't want any loose chunks floating about in that area. Wonder how well Moglice and Turcite play together?

Thanks for the responses...keep them coming.
Cheers Ross

Dear Ross,

If I was your Rebuilder I would have recommend you replace the Turcite when I saw it. You should depth Mic and see how thick that Turcite is now. It look to be almost worn out. To be honest I have no clue how thick it was from the Deckel factory, but the majority of new machine builders use .047" and then scrape it so you generally have about .040" when it's finished. From what I see, it looks like .010" to .015" if your lucky. It might be possible it was .030" when new may have been ground or scraped to .025". In all my years I have only seen .010 used on Hardinge beds and .020 on Okuma Howa VMC's. I usually use .047" or .062". If you can find a spot where there is little wear or unworn areas see if you can estimate how think it was when new.

Or can you check with the factory or their rep or does anyone else here know how thick it was when new? So if it is coming loose there then it probably is getting thin all over. Another issue I see is they machined the oil groves Tru the material. If you contact Turcite or Rulon mfg's they will instruct you to never cut the grooves though it. The major failure of Turcite is it is eaten away buy coolants and oil and comes loose or Rip's off when it gets to much contact. I would not use the old material to use as shims for Moglice as it is worn and it looks like it was scraped by your local Rebuilder?

In many cases the Tucite on the Z vertical ways is worn thin or is loose too. What does the opposite side look like? What do the gibs look like? How about the back straps?

The scraping on the machine looks great, but I would relieve the center 1/3 buy .001" -.002" of the Turcite as I have written before so as the dirt gets into the ends it gets better. Remember you have to think about ball screw alignment snd bring the gibs back to proper depth.

I think you would be money ahead to remove the old Turcite and replace it with Rulon 142 or Turcite. When you cut the oil grooves into the material cut it wider and don't go through it. I also used to sell Moglice and am very familiar with it's use. It would be a good product too if you are familiar with using it. No scraping is needed, just grind in the oil groves (or use weather stripping, if you look at Moglice website they show using foam strips), flake it, relieve the center and your done. But if your not familiar with its use I would do a few injections or putty jobs first. One thing about Turcite and Rulon it is forgiving and you can adjust it if you need too. Moglice..if you put it on wrong you have to chip it off and re do it as it will dull carbide, so its a real pain to scrape.

You can put a patch on it or put in some epoxy, but if it is thin there I would be afraid with in a few years it will be loose again and you will have to re-do it again.

I hope that helps.


Richard King
King-Way Scraping Consultants
10855 68th Street South
Cottage Grove, Minnesota (MN) USA 55016
651 338-8141
Handscraping.com
[email protected]

Steve:
Yes a patch is a real option i think....The idea of going a bit thicker and scraping to match might present the best chance for a good job done quickly....Thanks

Richard:
Your advice is welcome....I will measure the thickness. Height of this Turcite controls the "truth" of the vertical table ("X") My initial checks indicated that the table was a bit out at the bottom making the Turcite seem a bit too thick,
however i think that might be a false indication as the entire assembly should "nod" forward once the work table is mounted on the "X" slide...making it tip forward at the top.
(Just for reference the top of the "X" slide is controlled by a flat plate gib running against a ledge at the top of the vertical casting.)
Your point about the oil feed circles is well taken...

Cheers Ross

Examine the damaged area to see if there is loss of adhesion to the adjacent Turcite. The problem may be bigger than it seems. Find that out now first so you do not chase your tail later.
Cleaning, oil removal without damaging adjacent wear liner, is a concern. Remove a section of Turcite in a trapezoid shape into an area that is clean and without trace of oil contamination. Now heat can be directed at the contaminated section to sweat out the oil without putting heat directly on Turcite that is to be saved.
John

While I see what the designers were trying to do with the oiling grooves..

I think they cut it too close to edge of wear surface..

The pressure of the way oil will be trying to lift/undermine the thin tab of Turcite. I would not be surprised to see other side flake off also..

As even in a perfect world, everything moves.. That movement will be pumping oil back and forth across that area during maching ops...

If one side failed, it might just be improper suface prep, and only a localized adhesion failure...... or not.

On that class of machine... looks like a tough choice as to repair options.....

I don't have any answers for you Ross, but wow -- the construction of that Deckel is pure art!

I was just thinking you could take a chunk of wood like the end of a corn broom maybe 6" long and tap on the turcite to see if you hear any hollow points under it. This will show that the epoxy is lost it's bond to the turcite. I also prefer to put a connecting grove in a Z style oil groove as the oil distributes better across the ways. I was looking at the last close up picture again and it does not looked scraped, so if you scrape it, it surely will be to thin. When I was in Taiwan a few years back one factory had stick slip issues when the scraping depth was so thin. We measured it and it was .0001 to .0002" deep and the contact was about 90%. You know I teach 50% contact and as many low spots for oil as high spots for contact or weight.

Also the close up of the one circle the turcite is chipping off. bad deal :-(

I teach and scrape that you should have Turcite scraping depth .002" on average. After we scraped the machines so the depth was .002" and we relieved the middle 1/3 to create a "puddle or lake" of oil that is there all the time, it cured their stick slip issues. Many of the new machine factories over there use to cut the grooves to deep through the turcite. I wrote Tri-Star the biggest distributor of Rulon in the USA and they said if CAPS to never cut the grooves thru the Turcite! If you think about it Turcite squishes a little bit and if the depth is so shallow there is no place for the oil to go. The oil will not flow out of those circles if the depth is shallow. Not replacing it now that you have it apart I would think it would be a mistake. Deckel is a work of art as Robert says, but everyone makes a mistake now and then. I bet Deckel doesn't cut through the Turcite now.

lazlo said:

I don't have any answers for you Ross, but wow -- the construction of that Deckel is pure art!

Click to expand...

Art! It looks like a hodgepodge of bad ideas to me. Once you have a piece chipped off like that you dont get a consistant oil film layer when its metered the way it is IMHO

One more thing I missed. You said you measured and the bottom was a bit thick. We make things with a rise when it will sag from weight and wear. so the bottom being a bit thick sounds good. Once you assemble the machine and mount that big table it will sag from the weight and tip or sag square. I would bet with that much weight hanging out there so far you might leave it .001" to .002". When I scrape a Bridgeport knee top flats I leave it. .0003" to .0005" / 12" high toward the operator so as I assemble the saddle and table it sags square and as it wears on the top dovetail and bottom flats it wears better. If I made it square when I was building it up, the weight would sag it out of square and it would wear and wear bad, out of square.

IAMATT said:

Art! It looks like a hodgepodge of bad ideas to me.

Click to expand...

Could you be more specific ?
Cheers Ross

Richard:
thanks....good info here. Will look into doing the oil grooves without breaching the Turcite.
I think it was scraped, but it is not very deep.....Can't remember just now, but i think the mating slide is scraped....So there is some additional oil retention there..
I will report on the thickness tomorrow....
Your point about re doing the Turcite seems the way to go....Perhaps i could go with a thicker material so the grooving would not cut through...If the current thickness is OK for alignment, i would think
i could mill the seat in the casting deeper to cover the thicker Turcite....
Cheers Ross

I would replace the turcite since it is starting to peel.

Turcite is easy to work with and replace.

And even easier to scrape.

If you are going to replace the turcite, it seems like this would be the right time to rework the oil grooves. Fill the current oil groove machining in the casting with an epoxy to give good support to the turcite then cut new oil grooves in the new turcite.