I am in the process of making a spider that will fit on the back end of my lathe spindle. I have the metal sleeve bored for a slip fit over the end of the spindle, and now just need to drill and tap the four holes for the spider screws. My problem is how to locate the holes for the screws so that they are 90 degrees from one another. I don't have a rotary table, but I do have a drill press. I dont have a proper drill press vise, though. I'm sure there is an easy, ingenious way to do this, but I haven't quite figured it out yet.
Making a spider for my lathe-need help locating holes
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Do you have a 4 jaw chuck? Set the spider in the 4 jaw, indicate it, then you can use a turning tool to scribe the face of the spider using the 4 jaws as guide.
Once done, you can lay it on it's side and scribe the line along the side. I don't think the spider screws must be dead nuts exact, the one I made for my lathe was done as I described. Works fine.
I actually have my 4 jaw chuck scribed on it's side in 3, 4, 6 and 8 increments around it's circumference. I can use those increments for many things, muzzle brakes for one.
I'm quite sure there are other great methods to get the 4 spaces set up for you.
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Spiders and "splat"
There should be two rows/rings of tapped holes - one to hold the spider onto the lathe spindle and the other to locate and clamp the job that project back through the lathe spindle bore to the spider.
Accuracy is not essential either as regards the angular or axial placement/spacing.
Be very very careful with using that spider as if the work projects too far out from the spider or if the work projection:diameter is too large the job will start to "whip" and a very dangerous situation may develop. When that "whip" happens, it is something that you won't forget!!!
The "spider" can be eliminated or extended by a single or a series of ordinary compressed timber "stiffening/bracing" board drilled to suit and spaced out behind and in line with the lathe spindle. Hold the pieces of board so that they don't move easily - anything that will do the job will do.
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As Tiffle says if the work gets to whipping around it will get interesting real fast. Be sure to secure the spider to the spindle very good.
If your doing a one off and you don't use a spider much take a piece of 2x4 chuck it in a four jaw and drill it out for the size stock and turn the OD to be a snug tap fit into the spindle and use that then throw it away. You could also use a piece of a 4x4 post.It's only ink and paper
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Spider bites?
Thanks Carld.
That prompted another and perhaps better option from my days on turret and capstan lathes.
The quite long stock projecting from the back of the spindle did not have a spider at all. It was just a round tube that was on portable and adjustable stands in line with the axis of the lathe spindle bore. The stock just rattled around in the tube (noisy as hell). The capstan ans turret tubes/spiders had a "pusher" that was butted up against the stock. The "pusher" was connected by a wire to a weight that hung vertically. All we had to do was to place/index a work-stop on the lathe and open the chuck or collets and the stock would feed in, hit the stop, close the collets/chuck - and away we went.
Its simple and safe for everybody. Its easily made, erected and stored away until needed.
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Still a "goodie"
The big advantage of a spider as proposed in the OP is that it will support the job "over-hang" between the back of the chuck jaws or collets and the back of the spindle. This can make quite a difference to long and fairly small diameter stock that may be rotating at fairly high speeds.
So there is a good use for that spider as proposed - on the back of the spindle.
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I use a spider when threading, chambering or crowning rifle barrels. I indicate the bore in at the "working" end, then at the spider end, then go back to the working end and make sure that nothing changed. The screws on my spider are in line with the 4-jaw chuck jaws, and are numbered to match. Makes life easier!David Kaiser
“You can have peace. Or you can have freedom. Don't ever count on having both at once.”
― Robert A. Heinlein
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Originally posted by 38_CalI use a spider when threading, chambering or crowning rifle barrels. I indicate the bore in at the "working" end, then at the spider end, then go back to the working end and make sure that nothing changed. The screws on my spider are in line with the 4-jaw chuck jaws, and are numbered to match. Makes life easier!
This is exactly what I will be using the spider for.
I have learned my lesson about thin stock at high rpms. When I first got my lathe I knew next to nothing about operating one. It came with one tool bit and I proceeded to get every brass pipe nipple I could find and turn them into piles of brass chips. Then I went searching through the garage for any round stock I could find to turn into chips. I found a piece of 1/4" slick rod, about 36" long. I chucked it up and when I turned on the lathe, it ran true for about a second, then the end sticking out the end of the spindle turned at 90* and whipped around and caught my sleeve. After I regained my bearings and managed to hit the off button, I thought for a long time about the catastrophe I had just so narrowly avoided. I don't think I'll ever forget the first day with my "new" lathe!
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"...it ran true for about a second, then the end sticking out the end of the spindle turned at 90*..."
Thanks!! I've been looking for an easy way to bend some rod. I could just put four pieces of rod through the spindle into the four-jaw, hit the start switch, and waalah!!
RogerAny products mentioned in my posts have been endorsed by their manufacturer.
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