Making a Spider for the lathe

[mickri]

Other projects are on hold waiting for materials to arrive. Another thread was talking about lathe spiders and I always wanted one for my lathe. Realized that I can add a spider to my lathe by replacing the collar at the end of the spindle with a spider. Since the spider will be replacing the collar the spider will be a permanent addition to the lathe. Looked in the scrap bin and found a suitable chunk of 1018 2" round bar. The collar OD is 1.75". The threaded portion of the spindle where the collar fits is .500 long. Won't know the major and minor diameters or the TPI until I take the collar off to measure everything tomorrow morning.

My gut instinct tells me that I want this spider as short as possible. One I don't want this thing whirling around with bolts sticking out of it. I can see myself and/or other stuff getting caught in it. Not good. The other reason why I want it as close to the end of the spindle as possible is to be able to hold stuff that barely sticks out of the spindle.

I am thinking no more than 1.25" long. .500" for the threaded portion and .750" for portion with the bolts. Using 1/4" bolts center in the .750 portion would have the bolts .250" from the end of the spindle. Is this too close to the spindle? I have never used a spider before so I don't know how close the bolts can be to the spindle.

Educate me on spiders.

 

[mksj]

Spiders can be made in many variations, I use two sets of 4 holes depending on if I used set screws or allen cap screws so I had enough clearance, on may lathes when extended they can hit the cover or a cover retaining post. I normally do not leave them in if I am not using and you always want a locking nut for each bolt so they do not loosen and fly out and hit something. They are normally out of the way that they should catch anything. Also they are good for holding stock centered through the spindle but do not expect them to hold stock sticking out past the spindle say another foot. The bar can setup a vibration, bend and whip anything around it to a pulp or worse break off and do some bad damage or kill someone. I have including some drawing done by a friend based on my original design for the 1340GT.

Set of different bolts, the one on the right are allen screws with retainer nuts.

This is what it looks like on the lathe, note the tight clearance to the cover, and these do not show the locking jam nuts that I always use.

 

[jcmullis2]

Spiders can be made in many variations, I use two sets of 4 holes depending on if I used set screws or allen cap screws so I had enough clearance, on may lathes when extended they can hit the cover or a cover retaining post. I normally do not leave them in if I am not using and you always want a locking nut for each bolt so they do not loosen and fly out and hit something. They are normally out of the way that they should catch anything. Also they are good for holding stock centered through the spindle but do not expect them to hold stock sticking out past the spindle say another foot. The bar can setup a vibration, bend and whip anything around it to a pulp or worse break off and do some bad damage or kill someone. I have including some drawing done by a friend based on my original design for the 1340GT.

Set of different bolts, the one on the right are allen screws with retainer nuts.
View attachment 346164
This is what it looks like on the lathe, note the tight clearance to the cover, and these do not show the locking jam nuts that I always use.
View attachment 346169

Now that’s a good looking spider. I like the whole setup. Especially how you incorporated your indicator. That’s much like the spider I have envisioned. However, I was gonna make my bolts from hex brass rod but now I’m afraid they’ll be too soft after reading your reply. I don’t won’t stuff flying apart that’s for certain. What size are your bolts and did you add the brass ends or buy them like that? Really nice setup.

 

[mickri]

The only way that I can attach a spider to my lathe is to remove a threaded collar and replace it with the spider. I would rather that the spider be a permanent addition rather than having to do a R&R every time I wanted to use it. I would remove the set screws/bolts when not using the spider. I like how you added the brass tips on the set screws.

 

[jcmullis2]

Mine has 2 threaded collars, with the outer collar acting as a locking nut. The spider should easily replace my outer collar. I was gonna use brass bolts but I’ll probably drill and tap the bolts and thread a few pieces of brass to make the brass tips. My spider should work pretty good but I’ll be removing the bolts just in case

 

[mickri]

Mine has only one collar. It is held in place by a set screw that tightens a plug against the spindle.

 

[jcmullis2]

Mine has only one collar. It is held in place by a set screw that tightens a plug against the spindle.

From what I seen in the pic yours is a much more solid piece of equipment. Hopefully mine won’t come apart on me.

P.S. I located those brass tipped Allen head screws at grizzly for a few bucks if you’re interested.

 

[addertooth]

Another option is to machine some tapered nylon or Delrin buttons that screw onto the Part-Contact end of your spider bolts. They will scar the surface of your items even less, which may be important if you are turning a barrel which has been blued.

 

[mksj]

Make your own brass tips, why waste the money buying them. You center drill the screw on the lathe and can get some brass rod to fit and attached with some loctite. I also have them with ball bearings in the end and aluminum or brass fingers for barrel work. You would do an internal thread on the spider and just thread it onto the spindle instead of the lock collar. These are just examples of how it can be done.

 

[jcmullis2]

Make your own brass tips, why waste the money buying them. You center drill the screw on the lathe and can get some brass rod to fit and attached with some loctite. I also have them with ball bearings in the end and aluminum or brass fingers for barrel work. You would do an internal thread on the spider and just thread it onto the spindle instead of the lock collar. These are just examples of how it can be done.
View attachment 346228

I was gonna make them from hex bar until I read the post about stuff whipping and flying around. I liked the looks of his brass tipped and thought I’d make some like you said until I found a 4pack for less than $5 at Grizzly. If they are too small I’ll make some.
Your ball bearing idea sounds interesting. How do you keep the bearing in the drilled hole? My luck they’d fall out and ruin my part.