Any suggestions on getting it up and running would be appreciated.
14 1/2' S.B.
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N.R. Davis
- Posts: 21
- Joined: Sun Sep 04, 2016 8:01 am
- Location: Gods Country, Holyoke, Mn
14 1/2' S.B.
This showed up about Midnight, I kid you not! In sections the next day and up to my shop the next. Bed stripped down and sent off for re-grinding.
Any suggestions on getting it up and running would be appreciated.
Any suggestions on getting it up and running would be appreciated.
Re: 14 1/2' S.B.
Hi There,
Welcome to the Group!
I don't know your level of expertise so I will ask some questions.
Have you any machining experience? Did you send off the saddle,
tailstock and/or headstock to the shop doing the bed re-grind?
When a lathe bed is re-ground, there is a likelihood that the relationship
between the prismatic ways and flat way will change. Therefore,
it will likely be necessary for the members that mate to the bed to be
re-fitted to the bed. Normally, this will include the saddle, tailstock
and headstock.
The saddle will likely be worn and no longer fit correctly even before
the bed was reground. Saddles usually wear more on the ends than the
middle and develop a "rocking" motion (although very small and not easily
seen without precision measuring tools). Therefore, the saddle will have
to be re-scraped to fit the bed again.
The other problem with a bed re-grind and saddle re-fitting is that the
saddle will now sit slightly lower on the bed (by the amount that was
worn and ground away and the re-fitting (scraping) of the saddle to the bed).
This means that all parts that bolt to the saddle will be lower too. This
means the apron will be lower in its relationship to the lead screw.
Depending on exactly "how much" the apron is lowered, this could cause
the lead screw to rub excessively inside the drive worm in the apron and
bind when the carriage assembly is at the extremes ends of the bed.
Luckily, SBL's have their QC gearboxes and leadscrew supports bolted to
the underside of the front outer prismatic way and can be shimmed down
the corresponding amount needed to bring everything back into alignment.
this should include the rack gear too.
The tailstock will likely need attention too. Because they are slid back and
forth on the inner ways, the base casting will wear. usually this wear will
not be even and be more pronounced at the end facing the headstock.
This will necessitate re-fitting (scraping)the base to the bed. Also, frequently
the tailstock ram will no longer be in correct alignment. Tailstock rams will
wear so that they "droop" and the bore of the tailstock castings will "bell"at
the mouth of the casting. The best solution is to re-bore the upper tailstock
casting and make a new, oversized ram to fit the new bore.
All the wear and re-fitting of the tailstock will throw it out of alignment with the
headstock. There are two ways to correct this. The "old school" method is to
machine and/or re-scrape the underside of the headstock to lower it back into
alignment with the tailstock. The other way is to place the appropriate thickness
shim between the two tailstock castings (base and upper). This is the"lazy" method
but it works. Factory specs for the tailstock ram (when new) was for the center
of the ram to be .0000" to +.0030" higher than the headstock center (having the
tailstock center slightly higher than the headstock is so it will have better alignment
as the parts "wear in").
If you plan to do any of these things, I suggest you get a copy of Connelly's book,
Machine Tool Reconditioning. It is the "bible" on this subject. Unfortunately,
this book has become difficult to find and is usually pricey when it is available.
Anyway, this is enough for now. Good Luck!
-Blue Chips-
Webb
Welcome to the Group!
I don't know your level of expertise so I will ask some questions.
Have you any machining experience? Did you send off the saddle,
tailstock and/or headstock to the shop doing the bed re-grind?
When a lathe bed is re-ground, there is a likelihood that the relationship
between the prismatic ways and flat way will change. Therefore,
it will likely be necessary for the members that mate to the bed to be
re-fitted to the bed. Normally, this will include the saddle, tailstock
and headstock.
The saddle will likely be worn and no longer fit correctly even before
the bed was reground. Saddles usually wear more on the ends than the
middle and develop a "rocking" motion (although very small and not easily
seen without precision measuring tools). Therefore, the saddle will have
to be re-scraped to fit the bed again.
The other problem with a bed re-grind and saddle re-fitting is that the
saddle will now sit slightly lower on the bed (by the amount that was
worn and ground away and the re-fitting (scraping) of the saddle to the bed).
This means that all parts that bolt to the saddle will be lower too. This
means the apron will be lower in its relationship to the lead screw.
Depending on exactly "how much" the apron is lowered, this could cause
the lead screw to rub excessively inside the drive worm in the apron and
bind when the carriage assembly is at the extremes ends of the bed.
Luckily, SBL's have their QC gearboxes and leadscrew supports bolted to
the underside of the front outer prismatic way and can be shimmed down
the corresponding amount needed to bring everything back into alignment.
this should include the rack gear too.
The tailstock will likely need attention too. Because they are slid back and
forth on the inner ways, the base casting will wear. usually this wear will
not be even and be more pronounced at the end facing the headstock.
This will necessitate re-fitting (scraping)the base to the bed. Also, frequently
the tailstock ram will no longer be in correct alignment. Tailstock rams will
wear so that they "droop" and the bore of the tailstock castings will "bell"at
the mouth of the casting. The best solution is to re-bore the upper tailstock
casting and make a new, oversized ram to fit the new bore.
All the wear and re-fitting of the tailstock will throw it out of alignment with the
headstock. There are two ways to correct this. The "old school" method is to
machine and/or re-scrape the underside of the headstock to lower it back into
alignment with the tailstock. The other way is to place the appropriate thickness
shim between the two tailstock castings (base and upper). This is the"lazy" method
but it works. Factory specs for the tailstock ram (when new) was for the center
of the ram to be .0000" to +.0030" higher than the headstock center (having the
tailstock center slightly higher than the headstock is so it will have better alignment
as the parts "wear in").
If you plan to do any of these things, I suggest you get a copy of Connelly's book,
Machine Tool Reconditioning. It is the "bible" on this subject. Unfortunately,
this book has become difficult to find and is usually pricey when it is available.
Anyway, this is enough for now. Good Luck!
-Blue Chips-
Webb
Re: 14 1/2' S.B.
Not to change the subject, but I found this 6 page brochure printed in 1960 in some 'inventory' and wondered if someone else would like to have it in their inventory. PM me and I will send it along to whomever asks. Here are 2 of the 6 pages that might be of interest.
Sorry about the poor quality but I had to reduce the original .PDF and then convert it to a .JPG. It is a wonder it is still partly legible.
--earlgo
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
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Glenn Brooks
- Posts: 2930
- Joined: Mon Nov 10, 2014 1:39 pm
- Location: Woodinville, Washington
Re: 14 1/2' S.B.
Good gawd, they've doubled the price for the SB 9!
Mine was listed for $145 - in 1924.
Mine was listed for $145 - in 1924.
Moderator - Grand Scale Forum
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge
Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Re: 14 1/2' S.B.
Just donate the difference to Kitsap Live Steamers.Glenn Brooks wrote:Good gawd, they've doubled the price for the SB 9!
Mine was listed for $145 - in 1924.
I'm sure they would appreciate that!
