SBL Apron Feed Problem

Wmsbrg · Mar 6, 2020

Hi, New to the site so please be patient. I have an early 1980's Southbend Lathe made in Korea by Daejung America. The apron feed has stopped working. The drive shaft is OK so I know the problem is in the internal collar on the apron that the shaft rides in. There appears to be no keyway in there that would engage in the keyway of the shaft. Is anybody familiar with this type of feed and/ or lathe?
I am attaching a picture of the removed apron.

Thanks in advance for any help.
Tom

johnoder · Mar 6, 2020

My guess is that you are looking at a bearing feature. The only thing that needs a key/keyway is the internal works such as a gear/worm gear / whatever - that is not visible in the photo.

That currently invisible item could very well have sheared key issues

iwananew10K · Mar 6, 2020

should be pretty easy to diagnose.
there HAS to be a key or feature in the worm or gear inside there that engages the slot in the rod.

leave as is and just look down in while you turn the feed rod...do it in every postion of the selector....make sure the halfnuts are open while you do so the interlock isnt peventing selection the long and cross feeds.

could be its just not shifting out of the neutral position on the apron selector....watch those gears while you shift it.

if you can see the gears engaging but still no movement when you turn the feed rod then something is up with the worm/gear and or its key.
it is also possible that a gear that *should* be pinned or otherwise fixed to a shaft no longer is..ie- a sheared or lost pin there.
visually track the movement of the gears, move them by hand if needed.

steve-l · Mar 7, 2020

Tom, If you take the apron apart, the fault will be self evident.

Wmsbrg · Mar 9, 2020

I have removed the feed drive rod that has the keyway and have turned the spindle by hand. All the gears turn and the feed works in both directions. The problem is the there is nothing inside the spindle that fits into the drive shafts keyway. This is a SBL Model 500. Are you familiar with this lathe? Is there anyone in the US that may have knowledge about this machine and can fix it. Without a feed I'm sunk.

johnoder · Mar 9, 2020

The problem is the there is nothing inside the spindle that fits into the drive shafts keyway

Used to be if feeds "stopped working"

Key gone? Make a key

In some designs the key has a shoulder on each end - so it will be captive in the "spindle" when the shaft (with keyway) is installed

nt1953 · Mar 9, 2020

Older SB lathes had a key with retaining shoulders on each end. It would fall out when the lead screw was removed. VintageMachinery.org has nothing that new. Contact Grizzly (current owner of SB)

SBLatheman · Mar 9, 2020

Wmsbrg said:
I have removed the feed drive rod that has the keyway and have turned the spindle by hand. All the gears turn and the feed works in both directions. The problem is the there is nothing inside the spindle that fits into the drive shafts keyway. This is a SBL Model 500. Are you familiar with this lathe? Is there anyone in the US that may have knowledge about this machine and can fix it. Without a feed I'm sunk.

I don’t have a manual for the 500, but the 550 manual shows a T shape key in the middle of the sleeve.
South Bend replaced the 500 with the 550. The 500 was of a different design than the 550(both were imported from Korea)
Your key has probably worn away.
Ted

Wmsbrg · Mar 10, 2020

Thanks, That explains a lot as all I can see in the middle of the sleeve is a small round hole. Do you have a picture in the 550 manual showing this? Also I assume that the key may be available from Grizzly if I had a part number. The hole that I see is relatively small and can't understand how that diameter can drive the feed rod with the considerable torque needed but it must have worked. Maybe it's actually clogged with debris and is actually larger that it seems.
Do you think I need to remove the lower spring loaded plate to do this?

iwananew10K · Mar 10, 2020

imagine a key of a size that fits the slot of your feed rod.
imagine a small dowel pin pressed into that key.
that dowel pin is what fits in that hole to secure the key.

SBLatheman · Mar 10, 2020

Wmsbrg said:
Thanks, That explains a lot as all I can see in the middle of the sleeve is a small round hole. Do you have a picture in the 550 manual showing this? Also I assume that the key may be available from Grizzly if I had a part number. The hole that I see is relatively small and can't understand how that diameter can drive the feed rod with the considerable torque needed but it must have worked. Maybe it's actually clogged with debris and is actually larger that it seems.
Do you think I need to remove the lower spring loaded plate to do this?

From the 550 manual:
Item #98
PT2901010S KEY, T-TYPE

I don’t know if the 500 is the same.
I doubt Grizzly has it
Ted

The picture sucks :angry:

I can email you a better one if you send me an email.
[email protected]

SLK001 · Mar 10, 2020

SBLatheman said:
The picture sucks

Send it to me and I will post the full version.

SBLatheman · Mar 10, 2020

SLK001 said:
Send it to me and I will post the full version.

Sent. Thanks

SLK001 · Mar 10, 2020

Sorry for the delay... Out in the shop!

Wmsbrg · Mar 12, 2020

Thanks everyone. No one has the key so I made one. The old key was in place with a snap ring to hold it in place. It's easily removable after removing the bottom plate of the apron.

iwananew10K · Mar 12, 2020

good deal.

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