The new scraping thread

[eskimo]

PS that el-cheapo surface plate is grade 00, 2.2 um flatness.

what el-cheapo surface plate

[Pete F]

Ray how are you measuring the Squareness of the cylindrical square? I'm a little puzzled by your goal of 0.01 mm as that's not a measure of angle (ie 90 degrees), do you mean 0.01 mm in 150 mm or however long your square will be?

I'm meaning to make up a cylindrical square myself, but don't think my lathe is capable of sufficient accuracy. It cuts quite accurately for general turning, but this is a whole different level of accuracy.

Pete

[RayG]

Hi Pete,

I'll start a new thread tonight, rather than further hijack the scraping thread.

Regards
Ray

[Anorak Bob]

At a local swap metal a few years back, a bloke had on offer a pair of these cast iron plates (boxes). They were from the closed down pattern shop at Chamberlain John Deere. He was asking twenty bucks each or the pair for thirty . I bought one along with a bunch of small machinist jacks. It measures 450 x 250 x 115. The surface looks fly cut. It has served me well for marking out, given that nothing I have done so far has called for extreme accuracy. To elevate the plate to another level by means of hand scraping necessitates the acquisition of an accurate master but when I read about camelbacks, if one was to be used as a master, I find that these require accurate scraping. Sounds a bit like tail chasing.

What's the answer?

BT

[Stustoys]

BT,
Are you sure that its flycut and not ground?
Those marks don't seem to be traveling in a straight line. Which would suggest to me something more like a vertical spindle surface grinder?
I think it would be fair to say(and I hope Greg will correct me if I have this backwards) camelbacks are used to transfer the flatness of your master to your work piece and would only be used when spotting the work piece on the master wasn't possible or convenient.

Ray, I had be typing the same thing.
Stuart

[Greg Q]

Fellas here's the reply I got regarding larger granite plates.

800x500x130mm ##$720+gst
1000x630x100mm #$890+gst
1000x630x150mm #$970+gst

Prices don't include local freight.

[eskimo]

Fellas here's the reply I got regarding larger granite plates.

800x500x130mm ##$720+gst
1000x630x100mm #$890+gst
1000x630x150mm #$970+gst

Prices don't include local freight.

mmm? I'm interested

[Greg Q]

Sorry, I should have been more clear. Those prices were forwarded to me from Measuring Tools, Cutting Tools, Engineering Tools that RC linked. I posted that on the road from my phone, hence the short message

Here's the whole email:


Hello Greg,

Just getting back to you in regard to the granite surface plates.

800x500x130mm $720+gst
1000x630x100mm $890+gst
1000x630x150mm $970+gst

If you want one in about a month let me know ASAP and I'll try get it on
my next shipment. Otherwise the wait will be longer.

These prices also don't include freight cost from me to you. This will
depend on your location and what size you go for. Are you in Melbourne or
somewhere else?

Regards

Ariel

[.RC.]

The 1000 X 630 X 150 price is $100 less then I paid for mine..

[eskimo]

I posted that on the road from my phone,

you are a technological guru...

why would one get the 150mm over the 100mm thickness plate?..less prone to twist/warp etc?

[Anorak Bob]

BT,
Are you sure that its flycut and not ground?
Those marks don't seem to be traveling in a straight line. Which would suggest to me something more like a vertical spindle surface grinder?
I think it would be fair to say(and I hope Greg will correct me if I have this backwards) camelbacks are used to transfer the flatness of your master to your work piece and would only be used when spotting the work piece on the master wasn't possible or convenient.

Ray, I had be typing the same thing.
Stuart

I don't know Stu. The surface feels smooth. I may be wrong but if the thing was used in a pattern shop, absolute accuracy most probably wasn't a requirement. I've got no way of checking the flatness of the surface.

BT

[azzrock]

After getting distracted from something else on the spindle video thread I thought I'd start a new thread here. Some photos below of a triplet of scrapers. Top is a Sandvik Coromant carbide scraper sporting a replacement handle made from a pad saw. Below it a file-sized piece of CRS with a carbide tip brazed on-I bought it from Forrest Addy when I took the scraping class in Seattle a couple of years ago. The bottom one is made from an alloy handled screwdriver I bought at a flea market. a 12mm carbide tip is brazed on and rounded to a small radius for very fine work.

The Biax power scraper can be seen dangling from its tool balancer which I find a must for prolonged sessions.

The granite plate with a couple of drops of red dye spread with a printer's brayer. Its important to be able to see the pattern through the dye. This much will last a couple of hours of constant spotting.

I bought the red dye from Forrest too.

The tools are resting on the cast iron plate I'm scraping. You can see the pattern left after the last scraping cycle. I stoned off the surface with a diamond stone using a very heavy hand-much more than used when you approach a flat condition. This piece is still very hollow in the middle which you'd expect after years of use in a shop. (And moving with age)

Greg

hi greg
there were two things that have really grabbed my attention
in one of your photos there is what looks like a pneumatic scraper.
i must of led a more sheltered life than i thought. whats it like to use.
the other is. you went to america to study scraping.
that's simply amazing.
this raises so many questions. like i wonder what forrest andy would think
of these scraping machines. is forrest a normal type name in the us. if not
i keep thinking that shorly he lives in a cave. if not a cave then under a big marking out table.
i hope you dont mind me making these comments because your post is very interesting.
thanks aaron

[Greg Q]

you are a technological guru...

why would one get the 150mm over the 100mm thickness plate?..less prone to twist/warp etc?

Oh yeah, they call me Mr. Wizard.

I have to borrow my friend's son to program my VCR. Or at least I think its a VCR. It takes these shiny drink coasters as food and somehow makes music and films.

The surface plate specification calls for 150mm thick in that size.

Greg

[Greg Q]

hi greg
there were two things that have really grabbed my attention
in one of your photos there is what looks like a pneumatic scraper.
i must of led a more sheltered life than i thought. whats it like to use.
the other is. you went to america to study scraping.
that's simply amazing.
this raises so many questions. like i wonder what forrest andy would think
of these scraping machines. is forrest a normal type name in the us. if not
i keep thinking that shorly he lives in a cave. if not a cave then under a big marking out table.
i hope you dont mind me making these comments because your post is very interesting.
thanks aaron

That scraper is an electric one that I bought on ebay (badly listed, so it was very cheap). I refurbed it and had it re-wound 240v, that's why it looks good.). They are great for roughing to flat quickly, and if you add a variable speed controller can be used for very fine work too. However they can also put deep scratches if you aren't careful.

Forrest was I think a common name back in the day. He is a big guy, and bearded. He's a polymath though-not exactly a cave dweller. He recommends the Biax highly.

As for going to the US: I had a free ticket and a free place to stay, so it was cheaper than going across town!

Greg

[azzrock]

cool thanks for the reply. your trip would of been great. this really goes to show the depth of knowledge
floating around this site. were there other students of scraping there or was it awas this a 1 on 1 type of training set up. if you don't mind me asking what do you do for a living