Turcite for a benchtop mill - blue or green?

[bdurbrow]

OK, so I've got a benchtop mill (an old original Sieg X3, FWIW) that has been in a bit of a minor disaster: it's out in the garage, and the water heater - well... it didn't explode per se (and yes, I have seen that Mythbusters episode!), but it did vent a whole bunch of steam out the overload valve.

So, a bunch of the surfaces on it have rusted; and I am looking to recondition it by scraping the rusted surfaces and apply some turcite to the saddle and headstock. FWIW, this machine will be converted to CNC (well, already partially is, but some parts need replacement); so it's getting new ballscrews (chineese C5 DFU1605 on the X and Y, and probably C5 DFU2505 for the Z) and couplers; the existing motors on it are 500oz/in NEMA23 steppers for X and Y, and a NEMA34 which I believe is 1200oz/in for the Z.




Looking on Aliexpress (yeah - shoestring budget) I am seeing two different grades of turcite, a green one and a blue one.

The relevant differences seem to be:

Blue:
500 mesh "copper" powder (brass? bronze?).
Shore hardness > 50
Interlaminar tensile strength >16N/sq mm
Bearing >10N/sq mm
Coefficient of friction (both kinetic and static) <0.03

Green:
320 mesh "copper" powder (brass? bronze?).
Shore hardness > 60
Interlaminar tensile strength >14N/sq mm
Bearing >10N/sq mm
Coefficient of friction (both kinetic and static) <0.04

The turcite surfaces will be fitted with constant-pressure lubrication with proper oil distribution paths cut into the turcite, way wipers, and shields for the way surfaces.

My searching has not turned up a relevant thread (I could have just missed it, though...) so...

Given all of the above, which varient of turcite do you all think I should pick?

 

[Bakafish]

I think you are going to have a hard time scraping off enough material to allow space for most common applications of turcite. You would typically have the surfaces ground for that much material removal. But before doing that, have you actually disassembled and attempted to repair/scrape it as it is? How could the critical surfaces have gotten so badly rusted that some rust treatment and a rescrape doesn't get it working after one steam event? You also may find that just buying the replacement parts is cheaper than trying to fix the old one with expensive grinding and turcite application.

 

[bdurbrow]

As it happens with this particular machine, material removal wouldn't be required for installation of turcite - all that would be needed is two shims on the ball nut mounting blocks (or in this case, just making the mounting blocks taller in the first place as it's going to need new blocks because the new ball nuts are different than the old ones) and trimming down the Z axis block (something I can do myself as I do have a working mini lathe - got lucky on that one, it was somewhat buried at the time of the steam issue and didn't suffer the same damage as my other machines did).

The total cost for the turcite + glue will be about $50; or $30 if the glue is included (I'm not 100% sure on that one based on reading the listing - I'll have to ask the seller before ordering).

I'm looking at the turcite more for its frictional characteristics, not because I need to make up for a lot of lost metal. This machine is somewhat experimental anyway, so I kinda just want to see what results I can get. A decent dinner at the local diner (try saying that several times in a row fast ) runs about $35 here anyway, so even if I do end up having to scrape it all off and go with metal-on-metal (well, with some oil in between) I'm not going to be too broken up about it.

The mill is currently in pieces; and I have not started on the scraping yet. I'm still figuring out what I'm going to need for the project (thanks to a whole bunch of posts here and videos on YouTube I think I've got a lot of it figured out, but I'm always open to suggestions be they from the voice of long-standing professional experience or total newbies - and I'm sure that as I go I'll discover gaps in the knowledge that I've gathered so far).

For additional equipment, I'm looking at a larger surface plate (something I already need), hand scrapers (likely DIY), diamond discs for sharpening/shaping the carbide inserts, and some sort of straight edge (a camelback casting would be nice, but I might try to make one out of Versa bar - a post here from July 2022 indicated that a 1.5" x 3.25" x 24" section was so cheap that they had to order two to meet the $75 minimum order).

For materials/parts, I figure that I'm looking at the turcite + glue; C5 ballscrews, ball nut mounting blocks (DIY, so just some aluminum or cast iron), and shaft couplers.

This machine is sufficiently old that it doesn't look like it's being sold anymore. Grizzly seems to still have some parts for their version of it left; replacement of the table + column would be about $350 + shipping & tax... which is less than I had anticipated it would be but still substantial.

 

[memphisjed]

I never like pronouncing a thing dead, this machine is dead. Butcher it for parts on other projects.
You will be in same money converting this machine as getting used one already running. Just reality of it.
Want to make a cnc for fun- do that on something else than a mill. Router, wood lathe, taco folder.
Stone the ways and call this mill a drill press if there is any life left in it.

 

[bdurbrow]

Hmm... well, I already need all the other tooling for other projects, so I'm only looking at the parts cost.

The ballscrews + nuts on Aliexpress come out to about $250 for all three axes. Adding the shaft couplers, turcite, and materials for the mounting blocks brings it up by about another $100 or so.

Anybody know where I can pick up a lightly used or reconditioned benchtop machine with a CNC kit already on it with C5 ballscrews for less than $350 in the general Sacramento area?

(yes, I did just look in the for-sale section here and on eBay).

---

Even if it's an academic question; I'd still like to know the answer to the original question:

For this scale of machine - or any scale, actually - which version of the turcite would you pick, and why?

 

[justin1]

It's probly safe to chose either I don't think in your application it would matter maybe go with the with the lower coefficient of friction.

You may find better luck with your scale of CNC project and questions on a hobby driven forum as this forum doesn't really like hobby machines or hobbyist to a certain extent. Anything that falls out of the realm of a "professional work environment" can be meet with some harsh criticism.

The mind set of lots of professionals is different then hobbyists. Lots of problems seem to get fixed with a CC.

So if you want better answers to your hobbyist problems I would try hobby forums or pretend the machine your working on is bigger and made in the USA and leave out hobbyist details.

You Would of probly had better feed back with out the first two paragraphs. And centered your question around the properties of the Turcite your interested in.

 

[Richard King]

I disagree. I used to write on the hobby machinist forum and it was full of hobbyists who knew nothing but because of their status as a moderator they tried to argue with professionals like myself.

I can answer the majority of questions on wearstrip materials as I've been using several types in my 55 years of rebuilding. This forum has changed since it was sold. They nolonger let the bullies. Rule and you can discuss ant brand like Grizzly or Rung Fo. That was the old management .

 

[bdurbrow]

Not having gotten a specific answer (no blame intended - it's just the way the thread had evolved at the time), I had to make a choice; so I went with the green turcite. The idea behind that is that it's got a higher shore hardness so maybe it might have better chatter characteristics (although, as that's a resonance phenomena, I suppose it might just be different, as opposed to better). I guess I'll find out when it arrives.

FWIW, I included what I did initially because I generally feel that knowing the context is important for answering technical questions. I imagine that which one is best would vary based on how it's loaded, so...

P.s. - as it happens I do have a rather large knee mill that's been affected by the same disaster (and, no, it's not Chinese), but I figure that starting on the small one is a safer idea.

 

[justin1]

I disagree. I used to write on the hobby machinist forum and it was full of hobbyists who knew nothing but because of their status as a moderator they tried to argue with professionals like myself.

I can answer the majority of questions on wearstrip materials as I've been using several types in my 55 years of rebuilding. This forum has changed since it was sold. They nolonger let the bullies. Rule and you can discuss ant brand like Grizzly or Rung Fo. That was the old management .

Fair I've had mixed experiences with the hobby forums specially when it comes to welding and being a professional welder the things some people come up with is interesting.

I mostly lurk and read the older postings on this forum and some stuff I've came across some of the guys were pretty dismissive when questions were asking surrounding Chinese equipment or anything hobby grade.

I still like to get opinions from both sides as even a broken clock can be right twice a day. But have to be careful not to mix too much bad advice with the good.

Not having gotten a specific answer (no blame intended - it's just the way the thread had evolved at the time), I had to make a choice; so I went with the green turcite.

That's not too bad then. My newer king 10x50 mill used the green Turcite so as long as the AliExpress stuff preforms as intended probly could use on your larger mill aswell.

I've been eyeing up the AliExpress Turcite for a project but still in the process of hunting down all the equipment to be effective in scraping the stuff in as scrapping supplies don't come up very often on my side of Canada.

Currently working out a trade for a 36" camelback straight edge but haven't had luck finding appropriate surface plate used so I may end up buying a no name Grade A plate.

 

[Richard King]

I keep recieved emails from a Chinese turcite copier and I delete it. I know Rulon 142 from Tstar.com as they are experts in plastics. It's made in Mexico. I'm not sure where Turcite sold through other sellers comes from.