Turning Front Brake Discs - Min. Spec.?

There are decent manufacturers in China. You get what you pay for. A made in china rotor for $20 vs $75, I’ll bet you there’s a difference.

Ohh! Robin… I forgot that XJS is not front wheel drive.
Well, I’m not master of half-measures then…

I thought that Atty may catch it, but you’ve surprised me.
Toolmaker, you say…

While we’re on the subject of toolmakers and seeing that Robin is in NZ :new_zealand: , FWIW, my dad started out as a machinist (he worked back in the day for ANCO/“The Anderson Co.”, when they were still in IN, and, later, in the R & D department of Papermate Pen, when they were still in L.A. :roll_eyes:). Eventually he became a master tool & die maker and, starting out his own shop in our home garage, he eventually built it up to one of the largest tool & die cos. in southwest MO, designing all kinds of complex tooling, dies, production machines, etc… :triumph: Sadly, foreign competition in that trade (e.g. China, Asia, Europe, etc.) eventually drove his co. out of biz circa the early '80s, as it did many in that trade here in the U.S. :cry: In fact, I remember him saying it’s a good thing we did not get into a third world war, or we would be, “screwed, because our country is so dependent on the machining and tooling of foreign nations now”. He also was not into numerical machining (despite having a jr. college certificate in tool making & machining from El Camino College in L.A.), when that practice became standard. Time just went by him … :frowning_face: I mainly bring this up in that, at one point back in the '60s, Australia :australia: was needing master machinists so badly they made our family an offer to pay all our moving expenses, housing, etc. if we would relocate there and get permanent residency. My parents initially agreed to same, but at the last moment decided to stay in the U.S. and settle in rural SW MO instead of N. CA. (Bay area), where we were living at the time the offer was made. Will always wonder what would have happened if we had become Aussies. With my love of reptiles, bugs, etc. at a child, I probably would have gotten bitten by one of their very venomous demons and passed away. :roll_eyes: Anyway, just waxing a big nostalgic there … now back to our regular thread. :smile:

(oh, and if anyone was wondering, I did NOT follow in my dad’s footsteps in the profession/trade or w. his biz - maybe a mistake on my part there :thinking: Else, I might have been more “mechanic savy” and been able to work on my own Jags :smiley_cat: ).

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Our trades were affected in the same way with toolmaking off shore being more affordable. I got out of the trade in the first Global Financial Crisis, however the training never leaves.

Distasteful as it is, the interdependence of otherwise rival nations I suspect has kept us all out of another world war to some degree. Little comfort in a lot of ways but I hear war isn’t a lot of fun either. I don’t know that it will work forever but it’s something. I hear about so many initiatives to produce computer chips and what have you domestically and wonder what the long term implications of that will be. Isn’t overly difficult to blow up a very expensive factory I’d think.

All in all I don’t care where a thing is made, much like people I judge them on their individual merit. And I’m painfully aware of how many things I could not afford to own if I had to pay what it would cost to produce said thing in my own country. I bought a bench top power supply for $60 or so the other month with variable voltage and amperage and several other nifty features that I imagine would cost $500+ if such was even available from a domestic manufacturer. I’m under no illusion of it being the last word in its class of device but it’s plenty adequate for auto shop use and I’m happy to pay our Chinese friends for it vs not having one at all.

Brings up an interesting point, Wolf … if we had a store chain in the U.S. that only sold American-made products, how many Americans :us: would be willing to (pay the additional $$ to) shop there? Sadly, I doubt many … it’s the idea of “free enterprise”, ironically, to our own harm … :slightly_frowning_face: Speaking of not being able to afford one’s own domestic products, I remember when I was in Brazil :brazil: how, despite the great abundance of raw materials and resources that nation has, those resources are mostly exported to other countries in regard to most technological goods (e.g. cellphones, digital cameras, computers, etc.) to be manufactured, only to turn around and be sent back to Brazil for purchase at prices that many citizens there cannot afford to pay. :slightly_frowning_face:

You can find a lot of stuff made here, it’s generally boutique or niche market or near enough to it that it’s expensive as hell and if it exists at all it’s generally a product aimed at someone that can afford it. That’s not completely across the board, but more often than not. I think the more practical solution, which is slowly happening, is to convince China or such that if they make a product of more reasonable quality we’ll pay a reasonable price for it. Trouble is we’re a country full of cheapasses wetherby preference or necessity. Generally they give us exactly what we ask for, broadly speaking. I wouldn’t have half of the “stuff” I have if it all had to be sourced from the US, and many of us have made it a bit of an art finding the right combination of compromises in foreign goods. Things are getting better, but only where customer and vendor or manufacturer interaction is happening. Nobody is talking to the outfit in China that makes brake disks for example.

It’s a known fact that Americans won’t do certain jobs. Cleaning, planting or picking strawberries, certain construction jobs etc. Backbreaking but for certain immigrants, a lifeline.

We will never be able to produce goods as cheaply as China. Our DNA and what we expect to be paid is inherently different.

China can offer skilled labor at a price that skilled Americans would consider an insult.

I read somewhere that when the iPhone was introduced to the world then president Obama asked Steve Jobs why the iPhone could not be manufactured in the US?

He replied something along the lines of.

“Two weeks before the iPhone’s launch date the engineers discovered a flaw. After the manufacturer in China were notified, they got hundreds of skilled engineers back to the factory, housed them in dormitories and they worked in 24 hour shifts to fix the problem”

If only a portion of that story is true, it demonstrates whey the iPhone could never be make here.

Social issues should not be discounted. Americans, others, expect little girls shielded from the hazards of OSHA exempt factories, want chance at non state run retirement and health care, 6 day and less work-weeks, energy not primarily from coal, and even clean drinking water, et cetera. Little yellow-ish girls soldering I Phones with poor ventilation whilst land and water polluted by lithium mining, and then bare-foot Africans harvest the scrap mounds seams A Ok for the, well, I Phone types.

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You’ll be surprised knowing how many folks from your place emigrated to Europe. Mostly to get rubbish jobs, so they can live a life outside of trailer park homes or worse - live a regular life with type 2 diabetes. That’s slightly opposite to Michael Dudikoff’s movies…

Folks above are usually skilled and willing to learn. Harsh to say, however social differences mentioned by Jp2 are fading away between both places… (time to learn how to solder…?)

It is well known that that particular rotor is a waste of time to turn as are all the later Jaguar rotors, XJ40 and up. Even when they are true after turning, if warped and needing to be turned, they will continue to warp.
If you found someone that sold you one Centric, then buy another and make sure it is the same Centric part number and similar age as Centric makes them in batches and won’t necessarily be the same. That is particularly true after Dino sold the company to venture capitalists around 6 years ago.

Fun fact, I was taught way back in trade school and have heard from brake manufacturers pretty often that it’s actually quite rare for a brake disk to “warp” in normal use, rather what happens is they become unevenly thick from any of half a dozen or more reasons over time. Six of one half a dozen the other in practice but there are some things you can do to prevent it.

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Well, I also was watching a YouTube tech video where the tech was pointing out how sometimes it’s the wheel hub that is warped, although the rotor isn’t. :open_mouth: Only way to check that, as with rotors, is to measure the run out w. a dial indicator while turning it round on the car. I was not aware that was possible, and how could a hub become warped? :confused: btw, supposedly one of the common ways for (rotors? hubs?) to get warped (somehow) is when wheels are put on too tightly using an impact wrench on the lugs. That’s why at a shop you should always insist the final lug nut tightening be performed by hand (and using a torque wrench, ideally). :+1:

An out of true hub would not be the most amazing thing I’ve seen on a Jaguar of this vintage. Wouldn’t be too hard to correct though. I once used an on-car brake lathe that one of it’s talking points was that it would account for such as that. Haven’t seen one since but it worked well.

Actually, N.T.B. chain shops are using something similar to turn rotors today, Wolf. You simply remove the wheel (and anything else that might be “in the way”) and attach the gizmo to the rotor while its on the car. The gizmo turns the rotor while cutting it to the setting depth. Pretty neat. :sunglasses: Too bad they didn’t have those back when turning rotors was more common than replacing them. :slightly_frowning_face:

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That’s pretty cool, I haven’t been in a shop since I worked in one decades ago so I’ve no idea what they are doing now. It was a neat idea.

I had one of those in my Midas w’shop in the early 2000’s and the stand alone brake rotor machine.

I had an out of true hub on a Mercedes S class that I own. Could not get a decent disc runout measurement no matter what I tried, new discs included. Went to a U pull it and got a hub off a wreck. Fixed the problem. It happens.

I’ve had to beat wheels and rotors off cars from the rust belt, I always put a skim of anti seize or grease on them. Amazing how much that stuff can get ate up.

Here’s a quick demonstration video of the gizmo in action at a shop:

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