the curious case of Prince Engineers Ltd---------UK

JHOLLAND1 · Feb 27, 2019

around 1948 a crank pin grinder unlike any other was introduced to the UK market--Prince Engineers of Kingston on Thames

included in distinctive features are non-offset chucks--an indication of
unique advance/retract mechanism of wheelhead

my observation leads to conclusion that wheelhead pivots with filmatic assist
and the critical mechanism is swing down adjustable steady rest hard linked to wheelhead

steady rest has micro-finished carbide pads providing contact with main and rod journals

on the steady mechanism is micrometer dial which pulls wheel into contact with journal

it appears the Prince grinder had a 30 year run--I can find no offering more recent than 1978---and no indication this concept was welcomed outside of UK

yet another quirky/wondrous marvel of British Engineering

JHOLLAND1 · Feb 27, 2019

2

a major concern of the motion linked journal contact is out of round transference in grinding process

an example--I ran a hyster s-70 lift truck with perkins 203 cu in diesel 12 years with bad rod journal and pronounced knock
crank pin was egg shaped and 34 thousandths under standard factory specs

if the Prince mechanism were used for regrind--it would appear an inevitably
less than cylindrical grind geometry would be introduced

check out this vid of Prince in action and formulate conclusion

YouTube

john.k · Feb 27, 2019

It works on the centreless principle..........Charles Churchill also produced a crank grinder that worked on a centreless principle with a fixed wheelhead,but it relied on one other journal to steady the system.......Incidentallly,there are also small portable units for pins only ,as it doesnt matter greatly if the pins are off centre,whereas the mains must be all concentric.

Demon69 · Feb 28, 2019

Kingston is my stomping ground, ill get a pic next time im down there

.
Can understand the transfer of error concern. Three contacts, two pads one wheel, maybe positioned to work out any error as they arnt evenly distributed? Would like to get my head around the mechanics of this.

Tyrone Shoelaces · Feb 28, 2019

I always thought " Prince " was a US company, nice to know they were a UK outfit. Lots of British engineering companies went to the wall in the 1980's. In ten years we went from market leaders in many fields to a mere shadow of what we had been. The powers that be at the time saw no value in manufacturing. I'll just leave it at that.

Regards Tyrone.

Limy Sami · Feb 28, 2019

There are 2 Prince crank grinders both still in regular use within 25 yds of where I'm typing this.

One of the first things to bear in mind is they come from an era of much looser tolerances in IC engines, and shall we say the Prince was ''aimed at the lower end of the engine recon market.''

That said they are easy and quick to set up, and once you've learnt their ''funny little ways'' (which IMHO all machines have - and that's without the machinists

) Princes do pretty good job.

Re the ovality transfer issues, ……..some how (and I haven't a clue how) they work themselves out - to amazingly good levels

Limy Sami · Feb 28, 2019

Don't say I never do anything for you Patent Images

pressbrake1 · Feb 28, 2019

Works like a indicator on a vee block picking up the highs
Workshop next to me chucked his in the iron, he wouldn’t sell to me as he didn’t want anyone else to pickup his old customers

gbent · Feb 28, 2019

Similar mechanism is now accomplished with electronics for both crank and cam grinders.

prince-grinder · May 20, 2019

pressbrake1 said:
Works like a indicator on a vee block picking up the highs

Hi, I have just joined this forum after reading through the Prince Kingston thread. I currently own 3 Prince grinders, all 6075 models. I did have 4 but I regrettably sold one to fund something else. I am the only user and I keep them in fine fettle. They are a wonderful machine to use when set up correctly. Yes each machine is slightly different to use but one soon gets to know their ways.

I would say they are certainly still the most popular grinder around as I am often asked if I would like to sell one - which I swiftly reply, NO. They are also very accurate machines when kept in good order and well oiled. If a journal needs to be say 2.0022" (that is 2 tenths of a thou) I can do this quite accurately so the comment about them being out dated is a little harsh - as it comes to down the user really knowing their machine and job.

I also have a very rare camshaft re-profiling attachment for mine, of which I only know of 1 other.

The business of following the journal on two points is very easy to understand when the machine is running in front of you. Also by ones right knee are a pair of levers. These control the stroke and can also be used to raise or lower the wheel head away from a journal that is severely knocked out on say the TDC part. Thus maintaining the original stoke by grinding the underside or vice versa.

Prince themselves were trading well into the 1980's and also supplied machines from other makers as a UK agents. My Berco boring machine and 100T press were supplied by prince. I have all the dated paperwork and manuals, maybe 6" thick!

They are certainly my favorite machine and one day I hope to buy the "baby" model.

Limy Sami · May 20, 2019

Welcome aboard prince-grinder

where about's this sceptred isle are you?

Expom · Aug 5, 2019

Hi all, Bob Stark here, Came across this thread whilst thinking about my younger days as a budding engineer in the UK and started searching for Prince machines as I did my apprenticeship with them from 1969 to 1974.
:codger:

I have happy memories of my time with them and went through all the different departments to learn my trade, also I remember Vic Prince well as he was the original designer and actually patented the design back in the 1940s if I remember right.

I was also involved with the camshaft re-profiling attachment of which I built quite a few but eventually built by Berco in Italy (I think)! because it was cheaper than building them in the UK....Sign of the changing times!

The factory was at 14 Park Road Kingston upon Thames, and I wonder if it's still there? Having left the UK in the early 80s to work in Saudi, Hong Kong then settling in Melbourne it seems a distant memory.

I also remember that we sold many machines into the U.S. as we tested them with a 50HZ converter at our assembly shop, and I proudly slapped "made in England" stickers on the packing crates!

I have never seen a Prince machine here in Australia but I'm willing to bet there are a few around still as they were extremely well built and maybe TOO well built!

Happy to answer any questions you may have, Cheers, Bob,

Limy Sami · Aug 6, 2019

Hello Bob

''The factory was at 14 Park Road Kingston upon Thames, and I wonder if it's still there?'' ………..it looks like Google street view says no, if I've got my bearings right #14 is ''Alan Lloyd Motors''

Google Maps

noni2019 · Aug 19, 2019

6075

prince-grinder said:
Hi, I have just joined this forum after reading through the Prince Kingston thread. I currently own 3 Prince grinders, all 6075 models. I did have 4 but I regrettably sold one to fund something else. I am the only user and I keep them in fine fettle. They are a wonderful machine to use when set up correctly. Yes each machine is slightly different to use but one soon gets to know their ways.

I would say they are certainly still the most popular grinder around as I am often asked if I would like to sell one - which I swiftly reply, NO. They are also very accurate machines when kept in good order and well oiled. If a journal needs to be say 2.0022" (that is 2 tenths of a thou) I can do this quite accurately so the comment about them being out dated is a little harsh - as it comes to down the user really knowing their machine and job.

I also have a very rare camshaft re-profiling attachment for mine, of which I only know of 1 other.

The business of following the journal on two points is very easy to understand when the machine is running in front of you. Also by ones right knee are a pair of levers. These control the stroke and can also be used to raise or lower the wheel head away from a journal that is severely knocked out on say the TDC part. Thus maintaining the original stoke by grinding the underside or vice versa.

Prince themselves were trading well into the 1980's and also supplied machines from other makers as a UK agents. My Berco boring machine and 100T press were supplied by prince. I have all the dated paperwork and manuals, maybe 6" thick!

They are certainly my favorite machine and one day I hope to buy the "baby" model.

I want to ask you something
I have the Prince 6075 Machine
and i need the Spare Parts catalog for it
Do you have it?
Thank you so

Nasser Gad

DDoug · Aug 19, 2019

I think these work much like the "Sunnen On car crank grinder"

Unfortunately, following the journal limits the versatility of the machine to just restoring.

Not changing the stroke, correcting errors of position, etc.

Also, subarc welding up the crank journals has become commonplace (at least around here) and the aforementioned grinding/machine method would not work I'm afraid, trying to ride on a welded journal.

prince-grinder · Jan 11, 2020

digger doug said:
I think these work much like the "Sunnen On car crank grinder"

Unfortunately, following the journal limits the versatility of the machine to just restoring.

Not changing the stroke, correcting errors of position, etc.

Also, sub-arc welding up the crank journals has become commonplace (at least around here) and the aforementioned grinding/machine method would not work I'm afraid, trying to ride on a welded journal.

These machines are better than any other on the market today.

They were well ahead of their time in fact.

They are all fitted with stroke correction mechanism that will automatically set the stroke to where you want it so if a journal is knocked out, you can simply reclaim it by off set grinding.

There are virtually no spare parts available any longer except for the diamonds and grinding wheels.

As far as i know i have the most prince grinders of anyone in the UK.

prince-grinder · Jan 11, 2020

That is rubbish, my princes will a grind within 1 tenth of 1 thou, you must be using old and work out / poorly maintained machines.

I can set up and grind any crankshaft quicker and equally as good as anyone with say a later berco, zeest or churchill offset chuck machine. If there is a bet going, i accept it

People beccme lazy and instead of manually operating machines, just want to push buttons and keep their hands clean these days. i have a name for folk like that but it would probably get me banned.

prince-grinder · Jan 11, 2020

wrong on the sunnen point

john.k · Jan 11, 2020

I dont think Bob Stark will find one here ...Repco Pauer/Repco Warren and Brown also made conventional crank grinders here in a couple of sizes,and consequently there would have been a prohibitive tariff on any import machine,and at one time ,you even need to get Repco to give you a letter saying that they couldnt supply what you wanted in order to get an import licence for a machine....Yep ,the good old days of the tariff wall.

DDoug · Jan 12, 2020

prince-grinder said:
wrong on the sunnen point

Uh huh...what ever you say.
You aren't limited to 144 characters here ya know …..

the curious case of Prince Engineers Ltd---------UK

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