[How-To] Instant Spider for Sieg SC4 (LMS 3540)

[Semesa2]

I needed a spider for my SIEG SC4 (LMS 3540) lathe. It turns out the classic mini-lathe spindle terminates with the same thread, and so the LMS mini-lathe spider fits on nicely. Clearance from the spider body to the SC4's default 41 toothed gear is 13 mm, and the picture shows what the clearance looks like while holding 5/16" drill rod. If I add two other sets of cap head screws (1 set 0f 15 mm and one set of 10 mm) to complement the 20 mm ones that are part of the kit, I should be able to support anything up to the 20 mm max capacity of the spindle bore while keeping clearance. Perfect? No... But it is a serviceable alternative until I have time to make something a little nicer...

 

[9t8z28]

Nice mod! This is good to know if I ever need a spider for my LMS 3540 although I am not sure if I can use this particular spider. I upgraded the rear spindle bearing to a tapered roller and it takes up a little more of the threaded section on the change gear side of the spindle.

Question. I have never used a spider so I do not know what the need is for the additional different sized set screws. Why do you need different sized screws for different sized stock?

 

[Semesa2]

I would guess that you should be ok - that is, if the amount of additional thread required to preload the tapered roller bearing is on the order of that required (small) when modding 7x mini-lathes.

The additional different sized set screws are needed because there is limited clearance to the 41 toothed gear. The shorter sets of set screws allow you to hold any size stock up to the max for the spindle bore and still maintain clearance

 

[pgf]

What are the keyways for, on the outside of the spider?

 

[ChazzC]

What are the keyways for, on the outside of the spider?

Used to tighten (and unloosen) the spider on the back of the spindle.

 

[pgf]

Oh, of course! Thanks.