Karl Holtey - flattenning

[bugbear]

I was interested to note that Karl considers a surface grinder a bad choice for flattening a plane sole;

as grinding generates heat the structure would be compromised.

I'm assuming Mr Holtey know how to use a surface grinder to its full potential, so this is quite a statement, given how often a surface grinder is represented as the ultimate sole-flattener.

He is also rather careful to avoid any clamping distortion on the plane body when he (machine) flattens.

However, I do take issue on one minor point:

After peining, the amount of removal necessary to bring about a flat surface would be far too much for filing or abrading.

Filing simply takes more time and patience (and the correct use of a reference). The method I recommend is very accurate, but labour intensive, at least compared to machines.

However, to a home-shop worker, it has the remarkable benefit of proving consistent high accuracy with low(ish) capital cost.

BugBear

 

[Jamesc]

As an engineer I'd take issue with this statement. Certainly when dry grinding heat is generated. However if the machine is set up correctly you have a huge mass of cast iron to act as a heat sink so with care heat is not a problem.

However just about all commercial surface grinders have inbuilt coolant systems (as does my machine at home). With coolant even quit aggressive cuts can be made which no discernable heating taking place.

Hand methods can certainly produce good results (certainly good enough for all woodworking purposes), and I for one much prefer the look of hand scraped machines. Given that modern surface grinders are capable of producing optically flat surfaces so perfect that two pieces of metal can be joined by molecular bonding I think it fair to say that the surface grinder wins on flatness.

Perhaps a better statement would be a dry surface grinder if used too aggressively can generate sufficient heat to distort the sole.

If you really want to get technical have a look up the effects of carbon transfer from diamond grinding wheels into steel tools. A lot of very local heat is also required so I think we are all safe with our diamond stones.

Kind Regards

James

 

[Mikey R]

As an engineer I'd take issue with this statement. Certainly when dry grinding heat is generated. However if the machine is set up correctly you have a huge mass of cast iron to act as a heat sink so with care heat is not a problem.

Some of Karl Holteys planes are steel sole with brass sides, so maybe the two metals will distort like a bimetal strip when heated? Also, I guess there are more internal stresses with the dovetailed joints than in a cast iron plane?

 

[Jamesc]

Hi mike,

Sorry obviously didn't make myself clear. The huge mass of cast iron is the surface grinding machine. When I was taught to set one up we tried to get a good level of metal to metal contact to minimise any twisting loads and to allow any heat generated to harmlessly pass into the body of the machine. Modern coolant systems take away the heat so effectively that even on my own machine with a home-brew coolant system I cant detect any warming even after fairly heavy grinding. A surface grinding should be a finishing process so you shouldn't need to make very heavy cuts, my machine is graduated in 10ths of a thousandth of an inch!.

Anyway please don't think I'm criticizing Holtey's planes or techniques. It's just that like with any discipline if you ask 5 engineers the best way to do a job you will have 10 different answers. I just took issue with the seeming sweeping statement.

Kind Regards

James

 

[Mikey R]

It's just that like with any discipline if you ask 5 engineers the best way to do a job you will have 10 different answers.

So true!

 

[woodbloke]

you ask 5 engineers the best way to do a job you will have 10 different answers.

...and if you ask 5 different woodworkers the best way to hone a blade you'll end up with 1000's of different answers :lol: - Rob

 

[head clansman]

hi

just seen this thread as I've just arrived in Holland to visit my daughter , Karl was perfectly right , any plane which has had a grinder used to flatten it sole, is only fit for one thing in the bin . hc

 

[bugbear]

As an engineer I'd take issue with this statement. Certainly when dry grinding heat is generated. However if the machine is set up correctly you have a huge mass of cast iron to act as a heat sink so with care heat is not a problem.

However just about all commercial surface grinders have inbuilt coolant systems (as does my machine at home). With coolant even quit aggressive cuts can be made which no discernable heating taking place.

That's what I thought - and indeed, elsewhere on Karl's blog he shows a surface grinder, lubricant flowing, preparing his raw stock?!?

He does (tantalisingly) say of the miling:

Although time consuming this system does work and I can achieve some tight tolerances of +/- .0015. This is only a way of removing the excessive material. The rest of the flattening process is another story.

BugBear

 

[Mikey R]

hi

just seen this thread as I've just arrived in Holland to visit my daughter , Karl was perfectly right , any plane which has had a grinder used to flatten it sole, is only fit for one thing in the bin . hc

I wonder what tool Ray Iles uses to regrind the soles of his planes. He has a lot of old Stanleys and Records go through his shop, I doubt he grinds a scrapes them all by hand!

 

[matthewwh]

I must admit when I touched the sole of a plane being finished in the Clifton factory it was absolutely stone cold, they run a constant flow of coolant from a huge sump and the carriage pauses for a few seconds between passes, the whole process takes around 15 minutes per face. Mr H does mention that the grinding process is inappropriate for infill planes specifically, due to their thin walled box section although I don't fully understand why. Any chance you could expand on your earlier comment Martin?

I'm quite impressed that he matches Clifton and LN's accuracy standard of half the tolerance required by British Standards before he starts his flattening process!!! He says that he doesn't abrade them against a true surface but the only other way I can think of to improve upon 0.0015" is to abrade them against each other in threes - the same way that straight edges are made.

I'm certainly looking forward to the next blog entry!

 

[JohnCee]

hi

just seen this thread as I've just arrived in Holland to visit my daughter , Karl was perfectly right , any plane which has had a grinder used to flatten it sole, is only fit for one thing in the bin . hc

I wonder what tool Ray Iles uses to regrind the soles of his planes. He has a lot of old Stanleys and Records go through his shop, I doubt he grinds a scrapes them all by hand!

I realise that this is a rhetorical question, but he uses a surface grinder, just like Lie-Nielsen, Clifton and Veritas do.
With the greatest respect to all concerned, the suggestion that a surface ground plane is only fit for the bin is balderdash, poppycock and piffle.

 

[Mr Ed]

I'm no engineer, so I'm not going to enter the debate about the pro's and con's of the various methods of surface flattening. I have however dabbled in minor bits of toolmaking enough to realise that the products that Karl outputs are achieving unbelievable levels of accuracy and finish compared to what most can achieve. That being the case, I'm prepared to take his word for it that he knows more about the best way of doing these operations than the rest of us.

Cheers, Ed

 

[Karl]

I'm prepared to take his word for it that he knows more about the best way of doing these operations than the rest of us.

Cheers, Ed

I agree Ed - given his wealth of high end experience, I doubt ANY of us are qualified to disagree with his methods.

Cheers

Karl

 

[PaulO]

With coolant even quit aggressive cuts can be made which no discernable heating taking place.

I don't think throwing large amounts of coolant on the infill material is a good idea. If you look at the images he is machining the soles with the infill fitted, presumably as the infill may slightly distort the sides / sole. Although I thought the through tubes aimed to minimise that.

I would be interested to know if he surface grinds the base of the 98 and 982.

The other consideration is the size of the fixtures he uses to clamp the assembled plane may not fit under his grinder.

I knew someone who used to buy a new Aston Martin every year. As part of the deal he spent a week each year at the factory as a trainee learning a different aspect of its construction. I wonder if Karl would accept the same sort of arrangement. Just need to check down my sofa then my apprenticeship can begin.

 

[TheTiddles]

Let's see if we can't spark a full-on forum fight...

Bearing surfaces in medical implants, bits of space craft, reflectors in telescopes, machined components so accurate and precise they have replaced gemstones for calibration... are all made using commerical grinding techniques, they're that good.

So how come they aren't good enough for a wood scraper?

If only someone would use a stress-releived ductile alloy like bronze or cast iron to make planes, then we could have much more accurate planes for a fraction of the price of an infill plane... :roll:

Aidan

 

[Modernist]

What a load of self indulgent hype.

tolerances of 0.0015 are more than adequate for a wood plane and the suggestion that surface grinders render a wood plane compromised is rubbish.

Get real and get out there and do some woodwork instead of all this pointless anal discussion.

 

[bugbear]

I knew someone who used to buy a new Aston Martin every year. As part of the deal he spent a week each year at the factory as a trainee learning a different aspect of its construction. I wonder if Karl would accept the same sort of arrangement.

For the same annual expenditure, I'm pretty sure he'd be happy to!

BugBear

 

[bugbear]

What a load of self indulgent hype.

tolerances of 0.0015 are more than adequate for a wood plane

Heh. I don't think Karl is aiming at "adequate".

BugBear

 

[Modernist]

What a load of self indulgent hype.

tolerances of 0.0015 are more than adequate for a wood plane

Heh. I don't think Karl is aiming at "adequate".

BugBear

I wonder if he is aiming at making tools to plane wood or, perhaps, something else?

 

[PaulO]

tolerances of 0.0015 are more than adequate for a wood plane and the suggestion that surface grinders render a wood plane compromised is rubbish.

Get real and get out there and do some woodwork instead of all this pointless anal discussion.

A £1 digital watch from the petrol station tells time as accurately as a [insert name of expensive watch here]. However, lots of people would rather have the more expensive watch, me included. Holtey is making a product which exhibits superior engineering to all other brands of plane. All of my LN planes have required work on the sole (except the #8 ), chipbreaker and blade. Having completed that work they will probably perform as well as a Holtey. In his blog he acknowledges that the level of flatness he aims for is probably over the top. Fortunately there are plenty of people like me that admire his attention to detail and will continue to covet or buy his products.

I think a lot of the issues surrounding grinding of plane soles come from the difficulty in adequately supporting it evenly and without distortion. The top of a plane has all sorts of knobly bits to make holding it difficult. Stanley, LN, LV and Clifton have fixtures to allow them to attempt this for volume production. They are by no means perfect (or even arguably sufficient) as you can easily see if you hold a straight edge up to any of these brands.