Overhaul of a 9" SB model "A"
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Mosey
Well-Known Member
Dave,
Are you able to post your method of determining the proper height of the TS?
Your loyal fans are interested.
Are you able to post your method of determining the proper height of the TS?
Your loyal fans are interested.
Hi Mosey,
This is the method put forth by Connelly.
I test bar is installed between centers. One in the HS and one in the TS.
The test bar should be straight, round, and of a constant diameter
It is assumed with this technique that the TS is positioned to turn straight. If an indicator mounted to the carriage and positioned at center height and traversed along the side of the bar show's taper, adjust the TS so that it indicates that the bar is parallel with the travel of the saddle.
With that done
The dial indicator is then put on the carriage, and set to touch the top of the bar exactly on center. Move the indicator to the HS side and zero the indicator. Now move the saddle all the way to the tailstock side. Rise or fall will be determined directly from the reading.
For toolroom lathes up to 12" swing, the tolerance is 0- .0008" high at the tailstock......
Hope that helps Mosey!
Dave
This is the method put forth by Connelly.
I test bar is installed between centers. One in the HS and one in the TS.
The test bar should be straight, round, and of a constant diameter
It is assumed with this technique that the TS is positioned to turn straight. If an indicator mounted to the carriage and positioned at center height and traversed along the side of the bar show's taper, adjust the TS so that it indicates that the bar is parallel with the travel of the saddle.
With that done
The dial indicator is then put on the carriage, and set to touch the top of the bar exactly on center. Move the indicator to the HS side and zero the indicator. Now move the saddle all the way to the tailstock side. Rise or fall will be determined directly from the reading.
For toolroom lathes up to 12" swing, the tolerance is 0- .0008" high at the tailstock......
Hope that helps Mosey!
Dave
Mosey
Well-Known Member
Very helpful. Thanks!
I'm afraid to go down and check it!
I'm afraid to go down and check it!
Mosey,
Don't get wound around the axle with the tolerance...its the tolerance for a new or rebuilt lathe....not a limit for useability! If your within .005" you won't even notice unless your using very small drills or really fussy straightness tolerances.
Dave
Mosey
Well-Known Member
Yup. Mines a flame-hardened bed with zero visible wear, so that is no issue. I don't know however if the TS is original, so I need to verify whether they are of the same parents. We shall see.
Hey Mosey,
It will also depend on the amount of wear on the TS base. Mine had .018" so I just resorted to making a new one from bar stock.
I will probably set it .001" high and let her wear down for 40 years...I suspect it won't even be .001 low by then! :big:
It will also depend on the amount of wear on the TS base. Mine had .018" so I just resorted to making a new one from bar stock.
I will probably set it .001" high and let her wear down for 40 years...I suspect it won't even be .001 low by then! :big:
Tailstock wear can be deceiving - the operator's tendency to grab the back, lift and pull toward the tail end of the bed can cause a preferential wear at the front of the tailstock causing a tilt of the quill when extended. It's almost impossible to figure out where the quill centerline is going to be after scraping in the base. When I refit mine I thought I was going to have to replace a casting (actually, I was going to make a new oversize quill 1/8" bigger and rebore/hone to fit) but when the base was scraped to the ground bed and level I was out only .006", well within what can be handled by shimming the top on the base. .018 is pretty far from that, you start messing with the locking and centering mechanisms by then.
I started by getting the quil parallel to the TS body. The body had been dropped at some point in its life and the back had a ding that I took down to the original surface. Then I took the rocker out of the base and got it somewhat level and measured the. 018. .....VERY worn!
Dave
Dave
A small update,
I have selected a grind house to do the grinding. Once the PO is placed I'll let everybody in on the house
I have some bills to pay first so the grind will need to wait a month or two. Meanwhile, I will start to correct, repair or build the other parts that I don't need to spend money on.....just time
Work is ramping up again...so I may be sucked back into the long hours...so we'll have to see.
Be patient.
Dave
I have selected a grind house to do the grinding. Once the PO is placed I'll let everybody in on the house
I have some bills to pay first so the grind will need to wait a month or two. Meanwhile, I will start to correct, repair or build the other parts that I don't need to spend money on.....just time
Work is ramping up again...so I may be sucked back into the long hours...so we'll have to see.
Be patient.
Dave
Hi Don,
Thanks for the support!
Well.....it ain't gonna tickle...I'll say that! :'( :'(
But the joy of a quality tool always lasts longer than the pain of paying for it.....or at least that's what I keep telling myself! :wall:
Dave
Thanks for the support!
Well.....it ain't gonna tickle...I'll say that! :'( :'(
But the joy of a quality tool always lasts longer than the pain of paying for it.....or at least that's what I keep telling myself! :wall:
Dave
What I could be doing in the meantime......
Mod the Tnut for the AXA toolpost. That's easy
Complete the gib for the "T" slotted cross slide. I have the stock...
Complete the fitting of the Cross slide to saddle. Can I do it with an existing straightedge is the question.......mmmmm maybe. I'll fit the saddle to the bed after the grind job...
Check the Vertical milling slide for geometry ( flat, square and straight). Correct if required. It's a Myford copy of far eastern origin...want to take any bets?
AXA mountable High speed mill/drill spindle using 8mm WW collets Leave stock for height fitting later.
Spindle indexing adapter for F1 dividing head
Auxillary spindle drive for high speed spindle for "wheel cutting" and drilling.
This is what I want to "copy"....it was made by Rivett
I'll probably ditch the countershaft at the top though
LOTS TO DO!
Dave
Mod the Tnut for the AXA toolpost. That's easy
Complete the gib for the "T" slotted cross slide. I have the stock...
Complete the fitting of the Cross slide to saddle. Can I do it with an existing straightedge is the question.......mmmmm maybe. I'll fit the saddle to the bed after the grind job...
Check the Vertical milling slide for geometry ( flat, square and straight). Correct if required. It's a Myford copy of far eastern origin...want to take any bets?
AXA mountable High speed mill/drill spindle using 8mm WW collets Leave stock for height fitting later.
Spindle indexing adapter for F1 dividing head
Auxillary spindle drive for high speed spindle for "wheel cutting" and drilling.
This is what I want to "copy"....it was made by Rivett
I'll probably ditch the countershaft at the top though
LOTS TO DO!
Dave
Thanks for the interest Vince!
That would be the goal.....
The Aux drive is going to be a steel plate base and rubber feet and made up of pipe and pipe fittings. I'll need to make an appropriate drive and idler pulleys, but I have the motor already.
The bond a band belting should be stretchy enough to not need to put a tensioner on it.
Dave
