Turning Steel

WobblyHand said:
If you are like me, those saddle retainers don't get looked at often enough. Tightening them really helps with lathe rigidity. Last time I looked at them (last week) all the retainer screws were loose. I've had the middle screw fall out before. The middle screw is totally inaccessible when the apron is on the lathe.
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I look at them more often than I wish I had to. Someone above mentioned top down mod? Have to check that. To me, it would be a big part of the answer. I'd much rather be on top..... ;)
 
There are multiple people who have come up with a better way to maintain saddle retainers which are more solid, and effective. I would suggest you look into it. The mod is a simple one. I have not done it yet. But it is on my to-do list the next time I have a reason to remove the saddle.

The lathe is essentially a Sieg SC2, so the mods you find for this model will largely apply to a LMS 7350.

The Saddle Retainer, as it is designed tilts in at an angle, and only the edges of it make contact. The better design uses a flat to flat mating surface, which more surface area and rigidity. It makes for a more reliable (and less wear-prone) assembly.

I saw a really nice design on MadModder, where he made adjustable tapered brass gibs for his. The adjustments are made within easy reach.

By the way, I have an LMS 7350 too, and am rather happy with it. Out of curiosity, I tried to "wiggle" my apron, and it was rather secure. I have done a fair bit of steel with mine.
 
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Chip Monkey said:
BTW, using home ground hss and will absolutely brush up on geometry.
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Chip Monkey said:
Below 80 sfpm, not more than .015 per pass
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Haven't used a Seig lathe before but from the looks of it, you should be able to take a heck of a lot bigger cuts in 12L14. I agree with the other guys that you might want to work on the geometry of your tool. If you care to show us some pics of the tool, maybe we can give you some idea of how to make it better.
 
Chip Monkey said:
I know gibbs/ways are routine maintenance, I meant that by "carriage adjustment". I can get things nice and snug from the ways to the tool post, I was just expecting them to stay that way longer.

BTW, using home ground hss and will absolutely brush up on geometry. I never really thought carbide would be much good. Should I try?
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CCGT inserts for aluminum will work.

Post a pic of your cutter. The king of HSS for the small lathe, Mikey, is posting in your thread and will let you know.


Sent from my iPhone using Tapatalk
 
The saddle retainer plates (A.K.A. slide plates) _are_ a weak point of these lathes. But it isn't necessary to go to the extreme of making the oft-mentioned "tapered gib" modification. I dumped the OEM jack-screw approach and went with a much simpler method, basically using flat slide plates and shims to get the right spacing between the plates and lathe bed. I did that a few years back and haven't found it necessary to do any adjustments yet. In contrast to some of the other approaches, this one doesn't require any mods to the saddle, either.

I didn't even use metal for the slide plates. I used cast MDS-filled nylon, which is filled with molybdenum disulfide for lubrication. McMaster-Carr has it for not a whole lot of money. It WAS convenient to have a benchtop mill to shape the pieces but it's been done with a lathe and a milling attachment. Acetal would probably work just about as well for this kind of application, and, if your lathe is in a humid environment, won't absorb moisture and expand like nylon will. I haven't experienced that, but YMMV.
 
homebrewed said:
The saddle retainer plates (A.K.A. slide plates) _are_ a weak point of these lathes. But it isn't necessary to go to the extreme of making the oft-mentioned "tapered gib" modification. I dumped the OEM jack-screw approach and went with a much simpler method, basically using flat slide plates and shims to get the right spacing between the plates and lathe bed. I did that a few years back and haven't found it necessary to do any adjustments yet. In contrast to some of the other approaches, this one doesn't require any mods to the saddle, either.

I didn't even use metal for the slide plates. I used cast MDS-filled nylon, which is filled with molybdenum disulfide for lubrication. McMaster-Carr has it for not a whole lot of money. It WAS convenient to have a benchtop mill to shape the pieces but it's been done with a lathe and a milling attachment. Acetal would probably work just about as well for this kind of application, and, if your lathe is in a humid environment, won't absorb moisture and expand like nylon will. I haven't experienced that, but YMMV.
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Your suggestion is what I started with a few weeks back and I have things getting pretty close. I ditched the jack screws, made a pair of tool steel side plates, and I'm sneaking up on zero slop by adding a shim or shims every time I have reason to disassemble the carriage.

Your plastic side plate idea interesting. Thanks!
 
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