Overhaul of a 9" SB model "A"
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Checked the space available....no way to do two...it will just barely fit one!
Got the leveling/caster brackets and cross bracing done....time to mount in on the base....I always hate laying down and drilling holes in steel.
Dave
Got the leveling/caster brackets and cross bracing done....time to mount in on the base....I always hate laying down and drilling holes in steel.
Dave
Don1966
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Hey Dave this might be a dumb question, but if you put casters on the legs and you move the lathe say to another part of the shop. Will you have to relevel the lathe? I am knew to this so I do not know. Still here waiting for the finally.
Don
Don
Don,
Thank you for your interest.
You are correct, if I move the lathe, it will need to be releveled. The posts in the picture above are threaded leveling legs that will lift the lathe off the casters once I have it in place. To move the lathe, I will lower the lathe back down onto the casters and move it to where I need it. It only needs to lift a tiny bit to level it.
The leveling feet get the lathe level front to back and left to right. The leveling foot on the lathe takes the twist out if there is any.....and with a bed this long, there probably will be some. :
Dave
Thank you for your interest.
You are correct, if I move the lathe, it will need to be releveled. The posts in the picture above are threaded leveling legs that will lift the lathe off the casters once I have it in place. To move the lathe, I will lower the lathe back down onto the casters and move it to where I need it. It only needs to lift a tiny bit to level it.
The leveling feet get the lathe level front to back and left to right. The leveling foot on the lathe takes the twist out if there is any.....and with a bed this long, there probably will be some. :
Dave
Thanks for the kind words Rick!
Well that was a productive day!
I leveled up the bed on the base using a machinists level first to get close. Then I put my precision level (.0005/div/10")
on and checked and adjusted the bed reference surfaces to dead level in both directions. The leveling foot and my leveling feet worked great and my concrete floor is over an 1" out of level over 5 feet!
Then I mounted the saddle to the bed and put a level on the cross slide.....way out of level across the bed....ok maybe it's my table? So I mounted the table on the reference surfaces of the bed and the level said the table is parallel to the bed. OK I scraped the table right!...but why out so much?
The saddle either wasn't scraped in correctly or has worn more on the leadscrew side. It took a .010" shim to bring the level up on the leadscrew side....OK I'll deal with this later
I then traversed the saddle down the bed and noted the change in the level every 3 inches or so. I went from the far far right all the way to up against the headstock.
The bed has wear ( that's no shock ....it's 60+ years old!) and the wear is located about 8 inches from the HS....right where you would expect it, low on the front of the bed ( the leadscrew side).
The level read 6 divisions...which is .003" /10 inches. The ways on the SB are aproximately 5" (+/-) wide. That tells me the bed has approximately .0015" maximum wear on the front way. This is not much for it's age and is consistant with the amount of "degradation" I see of the scraping marks in the area in question. Additionally, I can't see any wear ridges in the area, so the wear can't be much. So at least the evidence is consistant with the data!
So now what!?.......
The saddle wear is a bit troubling, though I don't know if its really going to matter. I could rescrape the bottom to bring it level , but I will need to be careful that I don't adversly impact the leadscrew alignment...so I'll need to bring the front bearing down while I bring the rear bearing down more to keep the leadscrew alignment.......I'll need to really check the leadscrew alignment before I get to far down the road here......I am concerned about the front to back position at the moment, but I don't want too ahead of myself.
The bed wear is very small....suprisingly so! I checked for zero as I did my measurements and It all repeated quite well!
Guess I'll sleep on this and ponder the next move while I read up on Connelly.......decisions decisions!
Dave
Well that was a productive day!
I leveled up the bed on the base using a machinists level first to get close. Then I put my precision level (.0005/div/10")
on and checked and adjusted the bed reference surfaces to dead level in both directions. The leveling foot and my leveling feet worked great and my concrete floor is over an 1" out of level over 5 feet!
Then I mounted the saddle to the bed and put a level on the cross slide.....way out of level across the bed....ok maybe it's my table? So I mounted the table on the reference surfaces of the bed and the level said the table is parallel to the bed. OK I scraped the table right!...but why out so much?
The saddle either wasn't scraped in correctly or has worn more on the leadscrew side. It took a .010" shim to bring the level up on the leadscrew side....OK I'll deal with this later
I then traversed the saddle down the bed and noted the change in the level every 3 inches or so. I went from the far far right all the way to up against the headstock.
The bed has wear ( that's no shock ....it's 60+ years old!) and the wear is located about 8 inches from the HS....right where you would expect it, low on the front of the bed ( the leadscrew side).
The level read 6 divisions...which is .003" /10 inches. The ways on the SB are aproximately 5" (+/-) wide. That tells me the bed has approximately .0015" maximum wear on the front way. This is not much for it's age and is consistant with the amount of "degradation" I see of the scraping marks in the area in question. Additionally, I can't see any wear ridges in the area, so the wear can't be much. So at least the evidence is consistant with the data!
So now what!?.......
The saddle wear is a bit troubling, though I don't know if its really going to matter. I could rescrape the bottom to bring it level , but I will need to be careful that I don't adversly impact the leadscrew alignment...so I'll need to bring the front bearing down while I bring the rear bearing down more to keep the leadscrew alignment.......I'll need to really check the leadscrew alignment before I get to far down the road here......I am concerned about the front to back position at the moment, but I don't want too ahead of myself.
The bed wear is very small....suprisingly so! I checked for zero as I did my measurements and It all repeated quite well!
Guess I'll sleep on this and ponder the next move while I read up on Connelly.......decisions decisions!
Dave
Hi Bob
Thanks for the interest!
The bull wheel is approximately 5.19" to the PD, and I think it's 16 DP and 83 tooth
The tight space is between the teeth of the gear and the back gear pin....I have maybe less than 3/8" of space to get the holes into, and I need to make sure I can reach the holes when I use them!....The picture above kinda points this out I think... I would use 3/32" diameter index holes....but I have be able to reach past the back gear pin when it comes around
Dave
Thanks for the interest!
The bull wheel is approximately 5.19" to the PD, and I think it's 16 DP and 83 tooth
The tight space is between the teeth of the gear and the back gear pin....I have maybe less than 3/8" of space to get the holes into, and I need to make sure I can reach the holes when I use them!....The picture above kinda points this out I think... I would use 3/32" diameter index holes....but I have be able to reach past the back gear pin when it comes around
Dave
Hi,
Read up on Connelly regarding how to proceed with the bed. I think he answered my question.
He calls for the saddle to be scraped to template quality using the unworn area of the bed as a template. OK I can do that...then a full length straight edge for marking up... :big:...the bed is 54 inches long!..OK you can use a shorter one, but preferably more than half as long as the bed....see section 9
Using that logic, I need a straight edge at least ...30" long. I have a 12" x 18" surface plate which if I use the diagonal, could be used to make a 20" straight edge. Still not long enough. Even if I bought a 30 inch straight edge, I would need a reference surface at least that big to maintain the straight edge....which typically get out of wack and need to be tuned up .
That would require at a minumum a 18 x 24 plate....and not a cheap plate either! A good one!....all said and done, I'm looking at $500 used probably, plus $250 for a straight edge casting, and many hours of machining and scraping to get the straight edge completed....then the work on the lathe could start.......so call it $2000 with CHEAP labor rate :...namely me.
I could get the bed ground. I'm told there is a place in Texas that will regrind them....$2000 plus shipping seems to be the rate......
Now what is .0015" of wear worth ?
The tilt in the saddle can be taken care of with some cunning....using the bed as a template, and the level, I can turn the saddle without moving the apron mount by much. That would restore the saddle alignment.
Lots to think about........What do ya think?
Dave
PS here's one of the new leveling feet in use.
Read up on Connelly regarding how to proceed with the bed. I think he answered my question.
He calls for the saddle to be scraped to template quality using the unworn area of the bed as a template. OK I can do that...then a full length straight edge for marking up... :big:...the bed is 54 inches long!..OK you can use a shorter one, but preferably more than half as long as the bed....see section 9
Using that logic, I need a straight edge at least ...30" long. I have a 12" x 18" surface plate which if I use the diagonal, could be used to make a 20" straight edge. Still not long enough. Even if I bought a 30 inch straight edge, I would need a reference surface at least that big to maintain the straight edge....which typically get out of wack and need to be tuned up .
That would require at a minumum a 18 x 24 plate....and not a cheap plate either! A good one!....all said and done, I'm looking at $500 used probably, plus $250 for a straight edge casting, and many hours of machining and scraping to get the straight edge completed....then the work on the lathe could start.......so call it $2000 with CHEAP labor rate :
...namely me.I could get the bed ground. I'm told there is a place in Texas that will regrind them....$2000 plus shipping seems to be the rate......
Now what is .0015" of wear worth ?
The tilt in the saddle can be taken care of with some cunning....using the bed as a template, and the level, I can turn the saddle without moving the apron mount by much. That would restore the saddle alignment.
Lots to think about........What do ya think?
Dave
PS here's one of the new leveling feet in use.
OK this morning I releveled the bed using the ways instead of the reference surfaces. This required a slight twist of the bed to accomplish....like .001" over 54". It was very easy to do with the right side leveling foot which does this specifically.
This will not hurt anything on the lathe...especially considering the saddle has been working and it's out .010"!
I then put the .010" shim under the MPL while mounted on the cross slide and zero'd at the far headstock end (unworn) I then went to the other end (also unworn) and checked zero....still there. Then I went to the "valley" and checked and the dip was more like 3 divisions now or about .0007".
I'm going to leave the bed as it is with just a bit of cleaning up. I don't think I'll even be able to measure this in the part during operation.
I will however take the .010" tilt out of the saddle!....I don't think it will be that difficult...just work.
Then I'll be able to level the bed off the cross slide table. I can then clean up the leveling reference surfaces to be parallel to the bed position. And I'm in business!
OK that's the outside ways. I need to check the inside ways now. I'm trusting that they are no worse...but we'll see.
Need to get to the honeydo list.....
Dave
This will not hurt anything on the lathe...especially considering the saddle has been working and it's out .010"!
I then put the .010" shim under the MPL while mounted on the cross slide and zero'd at the far headstock end (unworn) I then went to the other end (also unworn) and checked zero....still there. Then I went to the "valley" and checked and the dip was more like 3 divisions now or about .0007".
I'm going to leave the bed as it is with just a bit of cleaning up. I don't think I'll even be able to measure this in the part during operation.
I will however take the .010" tilt out of the saddle!....I don't think it will be that difficult...just work.
Then I'll be able to level the bed off the cross slide table. I can then clean up the leveling reference surfaces to be parallel to the bed position. And I'm in business!
OK that's the outside ways. I need to check the inside ways now. I'm trusting that they are no worse...but we'll see.
Need to get to the honeydo list.....
Dave
south bends are quite insensitive to bed wear when it comes to how it reflects on the parts you make. actually, this can be shown... I tried to unearth my calculations but cannot find them now... anyways, I expressed the turned diameter as function of the drop in the bed due to wear (same front and back)... taking differentials, the impact on the turned diameter is very small... Now taking different wear drop front and back may change this conclusion, but this is fundamentally an empirical question...
I would not touch the bed. See if it holds accuracy that pleases you and only if it doesn't should you tackle this...
I think you are right that one should be leveling the ways, not the table not the feet... as per south bend and Connelly... yes, all dead level is a static test in Connelly, but this is home shop not NASA.
my $0.02.
take care,
tom in MA
I would not touch the bed. See if it holds accuracy that pleases you and only if it doesn't should you tackle this...
I think you are right that one should be leveling the ways, not the table not the feet... as per south bend and Connelly... yes, all dead level is a static test in Connelly, but this is home shop not NASA.
my $0.02.
take care,
tom in MA
Hi Tom,
Initial measurements would indicate...and say indicate...not confirm...that the rear V is worn .001 in the trough and the front about .003" with a difference of about .0015 - .002" shown on the level....depending on what datum you use to level the bed. In the above case it was using the original leveling references...I suspect I could halve that otherwise
This measured from the inside flat way which is pretty good the full length...and with a MPL on the saddle to measure twist.
My impression at this time is to scrape everything else as if I were to rescrape the bed. Scrape the saddle and TS base to template quality using the unworn area's of the bed .....I can then test the lathe with this wear and see how she does....as you stated. In the meantime, I'll see if I can put together a plan to scrape the bed in if required....the wear is small enough to be fairly easily done from a amount of stock to remove perspective. We have a good size surface plate at work, that maybe I could spot a long straight edge on after hours......if there is such a thing :
Lately there doesn't seem to be an end to how many hours I can work in a week!
Ah well....tomorrow I put in a new rain gutter on my porch! Thrilling! :
Dave
Initial measurements would indicate...and say indicate...not confirm...that the rear V is worn .001 in the trough and the front about .003" with a difference of about .0015 - .002" shown on the level....depending on what datum you use to level the bed. In the above case it was using the original leveling references...I suspect I could halve that otherwise
This measured from the inside flat way which is pretty good the full length...and with a MPL on the saddle to measure twist.
My impression at this time is to scrape everything else as if I were to rescrape the bed. Scrape the saddle and TS base to template quality using the unworn area's of the bed .....I can then test the lathe with this wear and see how she does....as you stated. In the meantime, I'll see if I can put together a plan to scrape the bed in if required....the wear is small enough to be fairly easily done from a amount of stock to remove perspective. We have a good size surface plate at work, that maybe I could spot a long straight edge on after hours......if there is such a thing :
Lately there doesn't seem to be an end to how many hours I can work in a week!
Ah well....tomorrow I put in a new rain gutter on my porch! Thrilling! :
Dave
lordedmond
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Dave
I know you have mentioned this in the past as things to do but how do you test for the convex saddle alinement relative to the head stock spindle centre line , ie to ensure that you can face off with the required 0.001 or so convex.
The reason I ask is that I see a lot of people refurbing lathes so of the far eastern variety they scape this and that ( one has bored out the head stock and fitted a tube to hold the bearings glued in ?? ) the bed /saddle may be good but what about the basic geometry of the spindle to bed to saddle , as I see it if that is not spot on you are lost at sea before you start
congrats on the work you have do to bring the old gal back to a useful life ,as I need personal wheels to get about so a task of that nature is beyond me physically
so I am afraid I have to fork out for new British Iron in the name of Myford
Stuart
I know you have mentioned this in the past as things to do but how do you test for the convex saddle alinement relative to the head stock spindle centre line , ie to ensure that you can face off with the required 0.001 or so convex.
The reason I ask is that I see a lot of people refurbing lathes so of the far eastern variety they scape this and that ( one has bored out the head stock and fitted a tube to hold the bearings glued in ?? ) the bed /saddle may be good but what about the basic geometry of the spindle to bed to saddle , as I see it if that is not spot on you are lost at sea before you start
congrats on the work you have do to bring the old gal back to a useful life ,as I need personal wheels to get about so a task of that nature is beyond me physically
so I am afraid I have to fork out for new British Iron in the name of Myford
Stuart
Hi Stuart,
I'm going with Connelly on this one. He outlines two methods for deal with this objective.
I'll use the carriage as a spotting template.....and I'll correct it as I go.
But to do the bed, I still need a straight edge of sufficient size.....and that's still a problem.
I guess the good news is that the saddle is messed up enough that I can do a lot before it really matters and it would still be an improvement! Besides being tipped .010" it was warped .003".... jI took the warp out, but it's far from "template" quality still.
Additionally, I'm going to continue to use the references surfaces for leveling and straightness checks. They are the best surfaces on the lathe. and as close to trustworthy as I can get.
Lots of things to think about still......There's a lot going on!....and I don't do this for a living so it's a major learning experience on my side too.
Looks like I have some straight edges to make too........
Dave
I'm going with Connelly on this one. He outlines two methods for deal with this objective.
I'll use the carriage as a spotting template.....and I'll correct it as I go.
But to do the bed, I still need a straight edge of sufficient size.....and that's still a problem.
I guess the good news is that the saddle is messed up enough that I can do a lot before it really matters and it would still be an improvement! Besides being tipped .010" it was warped .003".... jI took the warp out, but it's far from "template" quality still.
Additionally, I'm going to continue to use the references surfaces for leveling and straightness checks. They are the best surfaces on the lathe. and as close to trustworthy as I can get.
Lots of things to think about still......There's a lot going on!....and I don't do this for a living so it's a major learning experience on my side too.
Looks like I have some straight edges to make too........
Dave
lordedmond
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Thanks David
I will continue to watch your progress with interest
I was trained to scrape as an apprentice but not what you may at first think we had lots of very old electrical gear at the Iron works so as an electrician we had to scrape in the old contractor contacts ( I am talking about open switch gear mounted on 2 inch thick slate , no covers all live with just a rubber mat and your brain to keep you safe ) as well as this we had to scrape in the babbit bearings for the old motors and rotary converters
Stuart
I will continue to watch your progress with interest
I was trained to scrape as an apprentice but not what you may at first think we had lots of very old electrical gear at the Iron works so as an electrician we had to scrape in the old contractor contacts ( I am talking about open switch gear mounted on 2 inch thick slate , no covers all live with just a rubber mat and your brain to keep you safe ) as well as this we had to scrape in the babbit bearings for the old motors and rotary converters
Stuart
