Today I acquired...........

[Brad93]

What is this beauty ...

View attachment 379593


... and what does "to scrape the camelback" mean? Thanks!

Carsten

--

it's a cast iron straight edge. Yanks call them camel backs, the english term is a fishback.

Used as a reference surface in machine building.

 

[25.4_mechanic]

it's a cast iron straight edge. Yanks call them camel backs, the english term is a fishback.

Used as a reference surface in machine building.

Thanks. Brad,

so just like these but much nicer ...

only that this pair is on it's way to me


No, really beautiful that Camel-/Fish-Back!! And useful.

Carsten

--

 

[Pete.]

Those are machining parallels. They could be used as straight edges but they are a bit small and it's not their intended use. A camelback/beam straight edge is a reference surface so the level of finish is a lot finer. Scraping is one way to achieve that.

 

[25.4_mechanic]

Scraping is one way to achieve that.

Thanks, Pete.

But this one

seems to be precision-ground (right?), so that's another way to achieve that?

Can one say that scraping is to be considered the highest form of precision surface treatment or surface creation?
I always hear and read it with the flair of great respect and have the greatest jitters about it myself?!?!

Thanks

Carsten

--

 

[Brad93]

Thanks. Brad,

so just like these but much nicer ...

View attachment 379601

only that this pair is on it's way to me


No, really beautiful that Camel-/Fish-Back!! And useful.

Carsten

--

well they're parallels. Ground to usually a few tenths for high quality ones. Those I beam types are usually not particularly great for flatness due to the unsupported edges.

a straight edge is very heavily ribbed and designed as such that after heat treatment and seasoning, they are extremely stable. A straight edge is then usually planed flat then hand scraped to extreme accuracy.

A 2 foot square granite surface plate of a high grade can have a total flatness of around 5 microns. You then scrape your reference from a known good or calibrated surface plate.

For example, a devlieg jigmill is hand scraped to an accuracy of 0.0001" per 12". @pressbrake. colleague eric uses a reference straight edge of about 2 foot long if I remember correctly.

 

[Brad93]

Five microns in inches is two tenths 0.0002".

Over say 2 feet that's absolutely minute.

Using 'modern' electronic gauging apparatus or optical means (optical flat being the most simple for example), it's possible to measure flatness into the realm of millionths of an inch, and then into wavelengths of light.

 

[Brad93]

Five microns in inches is two tenths 0.0002".

Over say 2 feet that's absolutely minute.

Using 'modern' electronic gauging apparatus or optical means (optical flat being the most simple for example), it's possible to measure flatness into the realm of millionths of an inch, and then into wavelengths of light.

My best gauge blocks are flat to a tenth. Those are shop floor quality gauge blocks by todays standards.
The modern ceramic gauge blocks laboratory standard are flat to 0.1um which is 5 millionths of an inch.

 

[nickk]

Some repair items for toys,then a pack of bargain lighters and guess what,all 10 work.

 

[GSR]

A nice birthday present

 

[dan.taylor.1]

I've had my flex head ones since 2006 and not broken one yet.

 

[Memmeddu]

Bought my Christmas gift little bit later but worth it
Speeduino standalone ECU , little step towards a big goal.
It features
Injector control
Ignition control
Launch control
Boost control
Flatshifting
Soft/hard cut rev limiter


It takes signal from camshaft position sensor , throttle body,map sensor, intake air temperature sensor,rev RPM,lamba sensor

It's a good compromise for me
I am thinking to download a T-Jet map and adapt to the engine I'll go to use because have the same static compression ratio .
So no decompression as advised in the dedicated rally car thread I've made.

So I can do everything I need without to much headaches
Maybe found another car

 

[Farside]

View attachment 379750
Bought my Christmas gift little bit later but worth it
Speeduino standalone ECU , little step towards a big goal.
It features
Injector control
Ignition control
Launch control
Boost control
Flatshifting
Soft/hard cut rev limiter


It takes signal from camshaft position sensor , throttle body,map sensor, intake air temperature sensor,rev RPM,lamba sensor

It's a good compromise for me
I am thinking to download a T-Jet map and adapt to the engine I'll go to use because have the same static compression ratio .
So no decompression as advised in the dedicated rally car thread I've made.

So I can do everything I need without to much headaches
Maybe found another car

At last, something useful for an Arduino to do.

 

[The_Yellow_Ardvark]

I am going in!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Wait, a distraction.

A good blow torch.

 

[The_Yellow_Ardvark]

Yes a box.

A well packed box, for 2 items.

 

[The_Yellow_Ardvark]

Right I am free from the tool trap.
I have spent some money. I have had coffee.
I have had cuddles from a busty lady. Plus she brought lunch.
She declined my offer of a Braile test as well.

#
A nice old style vice.

Another Grinding paste tin full and a John Bull Puncture repair tin.

The opuncture rpair tin is pree WW! as the lid in stamped to form the brand logo.

A few hand tools.

A WW2 age lighter.

WW2 age firing circuit Volt meter, working as well.

A Dinky toy.

Usher Brewery Keg tap.

A rock in purple.

Not deep purple.

A Gold Self propelling pencil, with a bit of lead.
Yes it is lead.

 

[The_Yellow_Ardvark]

Oh yes.
A Mamod.

a early forward and reverse Traction engine.
But fitted with a Meths burner.

It has a "Long Boiler" and reused/recycled from an older style engine.

 

[sparkysy]

I have one of those lighters somewhere, is it an IMCO tripplex?
Good lighter!
Sy

 

[dobbslc]

She declined my offer of a Braile test as well.

 

[dan.taylor.1]

Right I am free from the tool trap.
I have spent some money. I have had coffee.
I have had cuddles from a busty lady. Plus she brought lunch.
She declined my offer of a Braile test as well.




View attachment 379774
#
A nice old style vice.



View attachment 379782


Another Grinding paste tin full and a John Bull Puncture repair tin.

View attachment 379785


The opuncture rpair tin is pree WW! as the lid in stamped to form the brand logo.



View attachment 379787



A few hand tools.

View attachment 379788

A WW2 age lighter.


View attachment 379791


WW2 age firing circuit Volt meter, working as well.


View attachment 379793


A Dinky toy.



View attachment 379794


Usher Brewery Keg tap.


View attachment 379796

A rock in purple.

Not deep purple.



View attachment 379797

A Gold Self propelling pencil, with a bit of lead.
Yes it is lead.

Those ck? Screwdrivers are one of my favourite handle shapes to use. Dad has a few.

 

[arian]

Those ck? Screwdrivers are one of my favourite handle shapes to use. Dad has a few.

I think they're Stanley. I've got a couple. Blue for pozidriv, red Philips(sp?).

You're right. They're very comfortable in the hand. Did about 10 thousand (well ) screws on glazing strips on greenhouses at one time.