surface plate Brisbane

[mic-d]

gday.

I'm looking to borrow some time on a surface plate, a biggish one, around 600mm long if possible. I want to scrape a #7 plane flat and my plate's not big enough.
Alternatively does someone know where I could get three cast iron blanks to generate my own standards? Perhaps you know of a dead jointer or a machinery graveyard where I could obtain a cast iron plate to flatten?

cheers
Michael

[new_guy90]

far out you would have your work cut out for you lol you must be keen if you want to scrape 3 huge plates lol

can you find some scrap glass? i think that long it would flex a lot oh it was mentioned over on HMEM that someone went to a cabinet makers shop and got an off cut of granite from in the sinks and stuff that maybe a better option

[mic-d]

far out you would have your work cut out for you lol you must be keen if you want to scrape 3 huge plates lol

can you find some scrap glass? i think that long it would flex a lot oh it was mentioned over on HMEM that someone went to a cabinet makers shop and got an off cut of granite from in the sinks and stuff that maybe a better option

Yeah maybe I am crazy, but they only need to be 600mm long by about 100mm wide.
I already use 12mm float glass for a stand in surface plate. It is not flat enough for anything over about 250mm long. Lol the granite bench tops, don't know why people think that it's flat. The offcut I have has variations in the many many thousandths of an inch, far worse than the float glass.

cheers
Michael

[new_guy90]

Lol the granite bench tops, don't know why people think that it's flat. The offcut I have has variations in the many many thousandths of an inch, far worse than the float glass.

cheers
Michael
really? that makes sense i mean why would it need to be ground to such a high tolerance :?

have you looked in Carba Tec? they sell a surface plate really cheap maybe a bit small but i think if you can cover 60-80% of the work to be scraped then you can over lap them and still make it very flat

[mic-d]

really? that makes sense i mean why would it need to be ground to such a high tolerance :?

have you looked in Carba Tec? they sell a surface plate really cheap maybe a bit small but i think if you can cover 60-80% of the work to be scraped then you can over lap them and still make it very flat


Thanks Patrick, you're right I was hoping for one a bit bigger, probably the big McJing one. Just a bit short on money and space to get it atm.
The polished side of the granite is far worse than the other, don't know if it's good enough because the texture is just wrong for a transfer plate I think..:?

Cheers
Michael

[bollie7]

I hope this isn't a dumb question, but I'm not a precision woodworker so please bear with me.
Does the plane need that level of accuracy? or do you want to scrape it to learn how to scrape.
Just curious

regards
bollie7

[mic-d]

I hope this isn't a dumb question, but I'm not a precision woodworker so please bear with me.
Does the plane need that level of accuracy? or do you want to scrape it to learn how to scrape.
Just curious

regards
bollie7

Hi Bollie, I wanted to learn to scrape for one. A plane may need to be that flat over particular regions, toe, heel and front of mouth. If you think of a plane as just a blade holder, and the sole keeps it registered correctly on the wood, and if I tell you at times in the last steps of using the plane to smooth some wood that you might be taking sub 0.001" shavings, if the sole runs out by even half that much you'll get results that make you want to sit down and have a cup of tea. Also, if the area in front of the blade is higher than the heel and toe you get reduced performance due to tearout.

Cheers
Michael

[bollie7]

Well, there you go. I didn't realise you could get those levels of accuracy with wood. Learn something new everyday.

bollie7

[new_guy90]

sounds like a good project my grandfather collects tools and gave this guy a call from the paper who said he had some precision levels and what sounded to me like a surface plate but he wanted about $250 for each thing and he hasn't called back i sure would have liked to have seen them

[soundman]

Mic...I did a #7 quite a while back.....it was fresh stock and .... bluntly it was like a banana.

Ih you want to scrape it....go a head, knock yourself out.
I did mine on the top of my saw bench with looong strips of sand paper.

I tell you it built up my sholders....there is a lot of material to get flat in a #7.....I decided that once it was mostly flat.. that was good enough.

now where the scraping realy come in is where the frog meets the sole....never seen a plane that didn't need some work there...I used a standard file with the end ground as a scraper.

.....there is no point going super accurate at the sole will move a bit with age (particularly if it is a young casting) and it will flex a little with the tension of the frog & blade....Not that I've ever seen much flex in this area.

If you end up deciding to lap it with abrasive......don't be timid with the grit and get your self a good long "flat thing" to work on.....with a #7 anything shorter than 1200mm is too short.

I'm not sure how flat the bed is on a Sawstop machine:D

cheers

[mic-d]

Mic...I did a #7 quite a while back.....it was fresh stock and .... bluntly it was like a banana.

Ih you want to scrape it....go a head, knock yourself out.
I did mine on the top of my saw bench with looong strips of sand paper.

I tell you it built up my sholders....there is a lot of material to get flat in a #7.....I decided that once it was mostly flat.. that was good enough.

now where the scraping realy come in is where the frog meets the sole....never seen a plane that didn't need some work there...I used a standard file with the end ground as a scraper.

.....there is no point going super accurate at the sole will move a bit with age (particularly if it is a young casting) and it will flex a little with the tension of the frog & blade....Not that I've ever seen much flex in this area.

If you end up deciding to lap it with abrasive......don't be timid with the grit and get your self a good long "flat thing" to work on.....with a #7 anything shorter than 1200mm is too short.

I'm not sure how flat the bed is on a Sawstop machine:D

cheers

whatever mate. I'm rather more rigorous in my fettling than "gettin a good long flat thing and chewing it up with coarse grit abrasive"

cheers
Michael

[soundman]

After I got it close I went up a few grits.......when I was finished it may not have been completly flat like my smaller planes but it was smooth and workable.

But first time you run it on some hardwood you'll get scratces in the sole anyway....then you do some nice clean pine or meranti and the polish out again.

with my first few and the smaller planes I was pretty fusy... (my fathers #3c sweet haart I got keen with)....when you start on 6's & 7's..particulary ones that arent flat to start with....the novelty soon wears off.

cheers

[mic-d]

You're wasting your breath mate. Lapped plenty of planes, always substandard results. I only scrape now. Easier, cleaner, faster. Plently of literature out there to tell you you'll almost always end up with a convex sole if you lap. Not up to me to convince you otherwise.

#4 restoration - Woodwork Forums (http://www.woodworkforums.com/blogs/mic-d/4-restoration-678/)
http://www.woodworkforums.com/f152/more-scraped-planes-116963/

[rusty steel]

My two bobs worth.
I probably know less about woodworking than I do about metalworking (which is not much) but I seem to remember reading somewhere that the base of a plane should be concave. Could this be to allow for wear?
Russell

[new_guy90]

sounds like a good point i suppose none of the cast iron plane soles are hardened how much do they wear? has anyone measured it? i would think if it is convex of about 0.05 then that would be fine :? or does having it dead flat work the best

[mic-d]

My two bobs worth.
I probably know less about woodworking than I do about metalworking (which is not much) but I seem to remember reading somewhere that the base of a plane should be concave. Could this be to allow for wear?
Russell

A plane can have a bit of a concave in it, like the plane in my blog here:
#4 restoration Installment Three - Woodwork Forums (http://www.woodworkforums.com/blogs/mic-d/4-restoration-installment-three-685/)

But this plane still has coplanar bearing points at the toe, heel and mouth. If a plane was truly concave, ie the toe an heel were proudest points, then as the rear end of the plane comes onto the work in a planing stroke, it will cause the mouth to ride upwards, diminishing the thickness of the shaving, maybe even to nothing. As the front starts to leave the work, the mouth will come back down to the work and the shaving will get thicker. You'll end up planing an outside curve into the work. Conversely, if the plane is convex you'll end up planing an inside curve into the work. The plane needs to be flat. But within reason. I don't mean laboratory grade flat. I'm going to add another entry to my blog soon about this.

As the OP, I'd really like to get back on topic to my original post (shoulda never mentioned a plane:doh::doh::doh:)

Cheers
Michael

[soundman]

You may be able to lay your hands on a spare wing from a table saw......then get it precision ground..... but you would want one that had some age in it..so the casting had settled down.

Lots of people are replacing one wing on their TSB saw benches and fitting one with a router hole in it.

Might be worth a trip to the local scrappers and see if they have a big old cast flat thing... and get it precision ground.

cheers

[new_guy90]

i can tell you now most tool making shops or fitting and turning shops will have ground plates from old jobs just sitting around, if your lucky you maybe able to find a suitable plate that they would probably sell you if you ask

[mic-d]

Hi Patrick, can you tell me what you mean by ground plates from old jobs? Are these plates that are offcuts from larger jobs? I suppose I should just call some shops, but don't really have a clue what to tell them I'm looking for!

Cheers
Michael

[new_guy90]

Hi Patrick, can you tell me what you mean by ground plates from old jobs? Are these plates that are offcuts from larger jobs? I suppose I should just call some shops, but don't really have a clue what to tell them I'm looking for!

Cheers
Michael

well some times jigs are ground for gang jobs and customers need stuff like plastic molds surfaced ground when these are no longer needed they just sit on the shelf and rust i cant say you could find a suitably large plate nor that it will be flat, with out holes or surface rust but it maybe worth a look into, a tool and die shop would be the best to go to as your average fitting and turning shop wont have the grinding equipment they do

[mic-d]

Thanks for the extra info Patrick.

Cheers
Michael

[mic-d]

Well call me stoopid but I just realised that I'll get a 500mm diagonal on a 400x300 granite plate and the longest thing I'll be scraping is ~540mm. Will I be able to get away with a 400x300 plate for work that length? I can get that size mcjing plate for $185 delivered to the wood show.

Cheers
Michael

[Graziano]

Well call me stoopid but I just realised that I'll get a 500mm diagonal on a 400x300 granite plate and the longest thing I'll be scraping is ~540mm. Will I be able to get away with a 400x300 plate for work that length? I can get that size mcjing plate for $185 delivered to the wood show.

Cheers
Michael

According to one scraping expert who posted on another forum recently, you can scrape up to twice the diagonal "with care". I'm assuming he's using lots of overlap when blueing/scraping.

[mic-d]

According to one scraping expert who posted on another forum recently, you can scrape up to twice the diagonal "with care". I'm assuming he's using lots of overlap when blueing/scraping.

Bewwdy! thanks for that, do you have a link to that thread? Looks like I'll go with that one then, at 35kg it's a bit more manageable than the 75kg 630mm one.
thanks

Cheers
Michael

[Graziano]

Bewwdy! thanks for that, do you have a link to that thread? Looks like I'll go with that one then, at 35kg it's a bit more manageable than the 75kg 630mm one.
thanks

Cheers
Michael

Here it is: Which cast iron straight edge type is better? - Practical Machinist - Largest Manufacturing Technology Forum on the Web (http://www.practicalmachinist.com/vb/general/cast-iron-straight-edge-type-better-203687/)

My memory must be going, it's the first post by a guy named Forrest Addy and he states that it's "chancy" with it getting trickier the longer the straight edge is.

[mic-d]

Here it is: Which cast iron straight edge type is better? - Practical Machinist - Largest Manufacturing Technology Forum on the Web (http://www.practicalmachinist.com/vb/general/cast-iron-straight-edge-type-better-203687/)

My memory must be going, it's the first post by a guy named Forrest Addy and he states that it's "chancy" with it getting trickier the longer the straight edge is.

Cool, Forrest is the man... Since it's only 40mm longer than the plate and light easy to manage I reckon it's doable. I'll get that smaller plate.

Cheers
Michael