Overhaul of a 9" SB model "A"

[steamer]

For those of you following along and wondering....how does he know its parallel?

I do two roughing cycles using the marking as a guide This controls flatness

I then do the next cycle based on the information I get from a dial indicator and an indicator stand...this controls parallelism.

Although it doesn't have very good bearing at the moment, it has potential and the area marked is parallel within .0005" which is good up to this point...as I said I'll start to throttle back a bit....this will take longer , but will be more controlled and easier on my arm!

Dave

 

[ttrikalin]

Dave,
Were I to start scraping a master -- say a straight edge ... Can I use aluminium? or should it be cast iron? can it be mild steel?

tom

 

[steamer]

Hi Tom,

What do you have for a reference?...It should be bigger than the part your scraping.

If your going to put the effort into making a master, use some good quality continuous cast iron. You can use other materials but they aren't as stable. Steel is harder and more difficult than iron. Aluminum is soft and easily damaged.

How you start is important. When you have machined you master, check it for flatness. If it's high in the center, like a see-saw, you will chase your tail. Instead make sure it's high on the ends so it sits down repeatably.

I would make a flat master as your first go. Is this just for practice or are you making it for a specific job?

Get that far and we can talk....

Dave

 

[steamer]

All

If this is way too much information, I can cut it back....

Let me know...and no worries...I asked.

Dave

 

[chuck foster]

Dave, as far as i am concerned keep the info coming :bow: :bow:

until you started posting this info i thought scraping was just to aid in oiling, never even considered it a way to flatten out machined surfaces.
it looks to be very time consuming and labour intensive but the results are worth it.

i have read this thread from start to finish twice and i am sure i will do so again !

thanks
chuck

 

[Captain Jerry]

Dave

I may never do this but watching someone else do it is interesting and entertaining. There can never be "to much good information." Keep it coming.

Jerry

 

[steamer]

Cool! Will do.


It would have been nice if my mill had done a better job of milling the table parallel.....a lot less work!
..but we'll get there.

Dave

 

[lee9966]

Just read this whole thread and it is very informative. I have a 1936 9" that I tore down, painted, and put new felts. Maybe I should give scraping a shot someday, but the bed is so worn it's hardly worth messing with.

Btw I don't normally comment on spelling, but this one amused me.
Scrape = Scraping
Scrap = Scrapping.



Lee

 

[ttrikalin]

Scrape = Scraping
Scrap = Scrapping.

Lee

:big:

 

[ttrikalin]

Hi Tom,

What do you have for a reference?...It should be bigger than the part your scraping.

If your going to put the effort into making a master, use some good quality continuous cast iron. You can use other materials but they aren't as stable. Steel is harder and more difficult than iron. Aluminum is soft and easily damaged.

How you start is important. When you have machined you master, check it for flatness. If it's high in the center, like a see-saw, you will chase your tail. Instead make sure it's high on the ends so it sits down repeatably.

I would make a flat master as your first go. Is this just for practice or are you making it for a specific job?
Get that far and we can talk....
Dave

Dave,

I got inspired by your thread. Since I saw your scraping for the first time, months back, I got hooked. I have acquired a copy of the machine tool reconditioning book (my brother found it, dunno wherefrom) -- and I'd love to try my hand at it.

I did buy a simple HSS scraper from ENCO, nothing fancy like yours -- and I do have a 9" by 12" chinese tombstone for a reference... and scraper's marking paste... I understand I should start playing with what I have and thin about obtaining real tools as I go...

I would like to eventually scrape in my south bend... but not in a hurry -- it is accurate enuf and smooth enuf for now...

take care,
tom in MA...

 

[steamer]

Thats a good book Tom for procedure, but it's thin on instruction.

Good to have , but not the only one.

I would definitely get this one also.

http://www.machinerepair.com/Book.html

Worth it's weight in gold

I use the E.S. Dyjak brand marking fluid shown in an earlier post

http://www.macraesbluebook.com/search/company.cfm?company=1507654

Get it...you'll thank me. If your using high spot...it's great but what a mess

The Dyjak stuff is much better from a cleanliness perspective

Use a brayer ( a hard rubber roller used by printers)

I don't have as good a result with the soft paint rollers...so I would save up for the brayer ( like $12 I think)

It works well and it will clean up.

Dave

 

[ttrikalin]

Thank you.
I just ordered the book and the DVD

Will get the marking compound you suggest also -- as well as the brayer...

thanks for this pointer,
tom

 

[steamer]

Hey Tom

Cool!

A hint.... a little dab will do ya! Try just a small drop...maybe .100 diameter drop on your 12 x 18 plate and roll it out even...you should still see the plate through the marking...otherwise you put it on too thick....thickness is key....just go for it and get a feel for it...it will start to make sense once you do and you read up.

Your looking for "bullseyes" not to paint Chevy Nova fenders.... :big:

A little bottle lasts a long time.

Dave

 

[steamer]

Did some more tonight. I have just about got the bearing carried across the whole part...meaning I have spots showing nearly everywhere....not enough to suffice for bearing, but to show flatness. I have a couple of tenths or so to go to make the bearing carry the whole way.

I'm going easy from here as it's easy to roll the edge of the part if I get agressive here.....a little at a time.

Parallelism is good...I'll need to put my tenths indicator on to really measure...as I'm using a .0005" one at the moment and it's showing parallel in both directions.

I needed to do a step cut to get rid of .0005" or so taper across the part
To do this you make a cut part way across cutting in one direction.

then

Make a cut across the whole part in the other direction going over the surface you just cut.

The result is you remove a "wedge" of material by taking more off one side than the other.....thereby bringing the surfaces closer to parallelism....provided you take down the high side! :big:...or you just made it worse!

Dave

 

[steamer]

AXA tool mount to share tooling I have already with my "Big" lathe



New 5" 3 jaw set true chuck with two piece jaws




Dave

 

[steamer]

OK The surface has carried...I'll start refining it tonight....after I spend the day raking leaves :
I'll try to post some pictures.


Dave

 

[steamer]

Alright

Here's where I started....just about carried all the way across the part

Better

Better still

Where I left it

What the marking on the plate looked like on the last mark up.

What I found once I finished was that the part was out of parallel left to right by .001! but parallel within a couple of tenths the long way ???

I take down the flat way to correct this ...tomorrow

Dave

 

[steamer]

Here's what it will look like....like it?

Dave

 

[Mosey]

Love it!
And for your next one, can you make it look Swiss? You know, all of those tiny snowflakes.

 

[steamer]

Flaking!

As you and I both have F1's We know what that is don't we!

I think that is called diamond flaking. I also think its done using the bump technique

I like the butterfly flake personally..
Problem is, I'm so inconsistant, that it looses it beauty....maybe in 30 years I'll get good at it :big:

I'll see if I can find out how the diamond is done...

Dave