Overhaul of a 9" SB model "A"

Home Model Engine Machinist Forum

Help Support Home Model Engine Machinist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Don1966 said:
. Looks like you did your homework on this one.

Don

Well........ maybe.

I was right in that the bed is not worn "bad".....but the rest of it wasn't so good!
Because I did all the other work, I'm now regrinding the bed.....because now it doesn't make sense not to. I don't want to match scrape a saddle and tailstock to a "mildly" worn bed....I would prefer it to be an accurate bed!

The saddle had WAY more wear than I would have dreamed (.010 on the front shear alone) ...as did the Tailstock ( .018 low).

In the end I'll have what I want. An accurate, reliable lathe for small work....but I suppose I could have waited for a "real" creampuff and just shucked out the cash....then again, I KNOW what's inside of this one, my scraping skills have much improved as a result, and I'll have a lathe that you can't buy today for 3X the money I've spent thus far. And thats great! it really is!

But man it's a pile of work!

::)

Dave
 
Well tonight I got a few more cycles in on the guiding dovetail. I took some photo's to show the progress, which actually went very quickly.

I marked up the CS first. To do this I took a short nap foam roller meant for epoxy application and cut a strip out of it. I then coated one edge with marking canode.
2012-05-23_20-47-03_476.jpg


Here's how I put the medium on the master of the CS
2012-05-23_20-46-51_308.jpg


As you can see, it's not touching by much here!
2012-05-23_20-43-39_418.jpg


I was glad to see that after two cycles it improved greatly!
2012-05-23_20-48-03_995.jpg


and after 1 more cycle it looked like this

2012-05-23_21-03-08_623.jpg


So we're almost there.....Next is the gib side for parallelism and we can get this part done!

Dave
 
Dave I am glad you are showing your progress as I am learning here about scrapping. I also bought a video on scrapping to give me more insite as to how to go about doing it. The video is guiet good, a guy by the name of Micheal Morgan. I also bought a scrapper to practice with. It is very interesting, on how to make metal straight by scrapping. I would of never believed it till I watch this guy doing it and how he did it. So I will continue to follow alone on your progress. Hopefully I can pick up more info from you. By the way your progress look very good.

Don
 
Thanks for the kind comments and encouragement Don!

Patience and elbow grease applied liberally.....

I have the same video! He knows his stuff!

I was getting a wierd mark up early on where it was carrying on one end but barely touching on the other side....what I figuired must be going on there was that the guided side gib must have worn warped....it came down quickly and "behaved" but it was wierd. I even marked the right side with the left side of the CS to make sure it marked the same way....which thankfully it did , cause if it did otherwise, that would have meant the CS had a twist in it.......I just kept going knowing eventually it would come in.

Dave


Dave

 
I have got some warping on my y axis on my mill. I ended up replacing it but that concerned me. I had a height problem when I fly cut. Every move I make to the next cut causes a step in the metal and I really need to retram it again, but I believe this is coming from my gib. If I can learn to scrap I my be able to correct some of this Chinese mill problem. First of all it is not that rigid and I quess I can't expect to much for the price. Same with my 7x14 microlux lathe lack of rigidity. Me being green at this does't help and I am trying to grasp all the knowledge I can about it. Hell! I am still learning how to operate a lathe an mill.

Don
 
Hi Don,

Thanks for the interstest and support!

It takes a while....just keep reading and doing....the doing is the very important part!
Experience is gained by doing.
As far as scraping is concerned, the best way to get a feel for it is to do it.

Do you have a surface plate?...They are REALLY cheap right now.
Get a piece of iron , your old mill part that you replaced that is now sitting doing nothing is a perfect victim, and just start....you have nothing to loose and everything to gain...if you straighten it out, you'll probably have a part better than the one you replaced.,,,,if you don't well, it can go back to the same spot on the bench it is now :big:

Start on the flat ways of the dovetail....easy peasy...I'm telling ya if you watch the video , apply brain and liberal elbow grease your will get a result. That result can be reviewed with a surface plate
RELAX.....that's important. You'll cut far flatter work if you relax and be consistant....and PATIENCE its not one of those things you can rush....
I like doing it as I tune out everything else....it's a nice band pass filter in that regard....so it gets my mind off other troublesome bits......machinists yoga!.....good thing I don't have to do it for a living! :big:

I don't by any means feel I am any where near an expert on the subject....I try not to lecture on the subject beyond what I know....but If I can get something as flat as my plate...you can.

Dave
 
Dave I do have a surface plate and the dye, but it will be a while before I even attempt to do anything with it.
Thanks for all the pointers, all of that sounds very interesting and I still need to grasp it all.

Don
 
OK got the guide side of the Saddle dovetail scraped to match the CS dovetail....marking showed well.

Couldn't resist the urge to try it out. NO gib in place mind you...

I put some way oil on the saddle and put the cross slide on. WOW

Like it's on glass....It sucked right in tight to the flat way and the guide side of the dovetail by capillary attraction and as slick as snot on a door knob!

I can pull the CS back and shove it forward, and it glides to a halt on its own in about 3 inches. NICE!

Thank god all that work was worth it! :big:

Still have to do the gib side....but we're just about there.

Dave
 
Steamer makes a point about surface plates being cheap.... at the moment, Enco is having a nice sale on several.

Example:
Sale price on a 12x18 surface plate is $45.95
http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=949402&PMAKA=640-0120

BUT WAIT there's more.... LOL, you can also use the MRTN code if your total is over $99 to knock off 10% (I never seem to have trouble with that restriction.... I can always find *something* else I want, LOL)

$41.36

Better yet? Code MRFS gets it shipped FREE. That's like $45 on that plate if you were to just buy it.

A surface plate that usually costs $130 shipped for $42.

Heck, I'm considering getting one just to bolt my mill to as a riser block, LOL. Dead flat... and really what could I throw at it that would flex or vibrate 3" thick granite?

 
Hey Dave make sure we get some photos of your progress. I am still here watching. Good to see that all the work you have done so far has made steps to completion and not a step backwards. Great work Dave, and I bet you are learning as you go also.

Don
 
Don1966 said:
, and I bet you are learning as you go also.

Don

Thanks Don! Oh you can bet it's been a learning experience!

It'll get done....it's just taking a bit longer than planned! Story of my life I think :big:

I'll see if I can get a clip of the cross slide phenomena...

Dave



Dave
 
OK best I can do with this droid...freakin jawa's! ;D



You'll hopefully notice the deceleration.....like a dashpot.

I'm shoving it pretty hard.

smooth as silk....and no gib strip,,,,and it never leaves the guiding dovetail,,,,it's sucked right in tight against by capillary action
 
LOL, it looks like it's on a spring or something.... that is just amazing!

Thanks again for the information and inspiration with this thread. It's both taught me a lot and removed some of the intimidation of the "Dark art" of scraping. I've got some projects coming up where I will post my learning curve, if I can get the materials and the free time together all at the same time. (New baby in 3 months... so that could be challenging.... LOL.)

Anyway..... just wanted to applaud once more your work and taking the time to document and share with us!

 
:bow: Now THAT is a smooth cross slide Dave. Looks like it was well worth all that scraping ;D

Kind regards, Arnold
 
Hey TroyO

At least scraping is quiet!....2-3 hours of Classical guitar and twin newborns doesn't fly I can assure you!

Thanks for the kind words Arnold! :bow:

Dave
 
Wow!! Dave that has really come together. It looks great, now as long as the rest goes good you will be set. You will be able to be proud of that lathe,because you have put you heart into Dave and your back. I envy your efforts and thanks again for sharing.

Don
 
Go Dave!!!!! :bow:

Smooth as.... you know what!!! :big:

Let me know when you are done and i will send you my address for shipping!!! ;D

Andrew
 
Dave,

It looks really good right up the the point were it grinds to a stop at the end.

I think you need a little more practice at scraping.
I'm willing to let you come and practice on my machines! ;)

Very nice work there! Thm:

Rick
 
Gib and gib screws this weekend, along with compound clamp screws

Edkolt on PM graciously loaned me the "communal" SB9 gib clamps ,,,,and I need to get them back!

If I have time I'll finish up the saddle gib side dovetail and scrape in the gib strip.

The next item to scrape is the top of the Tailstock Base....to make it flat and have good bearing with the bottom of the Tailstock. Alignment with the HS will come later.

Bend grinding is coming........I am sure that will be a case of "it hurts so good......" $$$$$ ::)

Dave
 

Latest posts

Back
Top