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Spiders, no not the 8 legged type, but normally 3.
Used predominantly as a backstop for typical self centering chucks, or can be any number of jaw chucks
either self centering or independent.
I made this one as per the attached? photos out of phosphor bronze, why ?? because it used to be readily available locally. But any material will be OK. Please read next post.
The center portion is relived out in 3 places to allow the jaws to come closer together, maintaining?
a solid portion at the rear which is a snug fit into the chuck bore and clears the rear scroll end of the jaws.
This spider shown is designed for a 100 mm dia chuck with the bore opened out to 22 mm.
The front face has a detachable screw which if used can accurately set the distance of short pieces being held
in the jaws.
Hope of interest.
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John
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What/Why? Sorry John I do not see what you are accomplishing with your spider.
I usually think of a Spider on a lathe as being on the tail end of the spindle to keep a long piece centered in the spindle.
I do not see what your spider is doing besides limiting the travel of the jaws.
Ralph
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Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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It will also hold stuff from slipping back into the hole in the chuck while you work on it, which is also useful.?
Bill in oKC
William R. Meyers, MSgt, USAF(Ret.)
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
On Saturday, July 11, 2020, 01:08:06 PM CDT, Ralph Hulslander <rhulslander@...> wrote:
What/Why? Sorry John I do not see what you are accomplishing with your spider.
I usually think of a Spider on a lathe as being on the tail end of the spindle to keep a long piece centered in the spindle.
I do not see what your spider is doing besides limiting the travel of the jaws.
Ralph
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Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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On Sat, Jul 11, 2020 at 11:08 AM, Ralph Hulslander wrote:
What/Why? Sorry John I do not see what you are accomplishing with your spider.
Commonly used to either make a series of parts with all the same thickness (plus or minus), or to face off a single part so that both faces are parallel (again, plus or minus).
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Also, I wanted to add that I have used parallels for the same purpose, but they can be tricky to hold in place while tightening the chuck and difficult to remove after the chuck is tightened (which you MUST do to keep them from slinging out of the chuck!)?
This is pretty much one of those tools you always wish you had taken the time to make when you didn't need it.
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I "think" I understand, once again I need to see a video of it being used. If one is using the spider for thickness tan I would guess you might need a set of them of different thicknesses.
Ralph
On Sat, Jul 11, 2020 at 7:04 PM Fast Eddie < epinnell@...> wrote: Also, I wanted to add that I have used parallels for the same purpose, but they can be tricky to hold in place while tightening the chuck and difficult to remove after the chuck is tightened (which you MUST do to keep them from slinging out of the chuck!)?
This is pretty much one of those tools you always wish you had taken the time to make when you didn't need it.
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
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The front face has a detachable screw which if used can accurately set the distance of short pieces being held
in the jaws.
As John says, it is adjustable. Let's say that you had 10 pcs. of a 50mm? diameter washer you are using for spacers and they are 6mm thick but you need 5mm. That's not much for the jaws to grip so your piece wobbles like crazy when you chuck it up. Your washers are going to end up wedge-shaped, which you don't want. You need them flat with faces parallel. Also, you need to be able to set the washer depth reasonably accurately in the jaws so that enough sticks out to allow you to face off 1mm of material without hitting the jaws. When you finish the setup for the first one using a spider, and have it turned to size, you then set a stop or a travel indicator on the carriage or the cross slide and do the remaining 9 pieces. It takes longer to explain it than to actually do it if you have the spider. Like I say. I've used parallels (like you would use in a vise) for this purpose, and I wish I had a nickel for every time I've had to fish one or both of them out of the chip pan
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Ralph? Basically they are workpiece?end stops. Example. You have 20 pieces of sawn bar say 1 " long, that need to be finished to a final length? of .9" First op, face one end to clean up say .95" with or without the?spider. Second op, the faced end pushes against the spider face, set the saddle? to produce the .9" length, lock the saddle, and face. Now you can repeat all other 19 parts to the same length by only swapping parts in and out the chuck.
John
What/Why? Sorry John I do not see what you are accomplishing with your spider.
I usually think of a Spider on a lathe as being on the tail end of the spindle to keep a long piece centered in the spindle.
I do not see what your spider is doing besides limiting the travel of the jaws.
Ralph
--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer
--
John
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Fast Eddie Well explained the dangers?of parallels in this situation. Thanks
On Sun, 12 Jul 2020 at 04:49, Fast Eddie < epinnell@...> wrote: The front face has a detachable screw which if used can accurately set the distance of short pieces being held
in the jaws.
As John says, it is adjustable.
Let's say that you had 10 pcs. of a 50mm? diameter washer you are using for spacers and they are 6mm thick but you need 5mm. That's not much for the jaws to grip so your piece wobbles like crazy when you chuck it up. Your washers are going to end up wedge-shaped, which you don't want. You need them flat with faces parallel. Also, you need to be able to set the washer depth reasonably accurately in the jaws so that enough sticks out to allow you to face off 1mm of material without hitting the jaws.
When you finish the setup for the first one using a spider, and have it turned to size, you then set a stop or a travel indicator on the carriage or the cross slide and do the remaining 9 pieces. It takes longer to explain it than to actually do it if you have the spider. Like I say. I've used parallels (like you would use in a vise) for this purpose, and I wish I had a nickel for every time I've had to fish one or both of them out of the chip pan
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John
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I forgot to add, you can make the thickness of the slotted spider face whatever? you need, especially useful for holding thin washers or parts. So you could have a range in 3 D printed spiders say 5, 7 , 10, 12, 15 mm thickness.
John
Fast Eddie Well explained the dangers?of parallels in this situation. Thanks
On Sun, 12 Jul 2020 at 04:49, Fast Eddie < epinnell@...> wrote: The front face has a detachable screw which if used can accurately set the distance of short pieces being held
in the jaws.
As John says, it is adjustable.
Let's say that you had 10 pcs. of a 50mm? diameter washer you are using for spacers and they are 6mm thick but you need 5mm. That's not much for the jaws to grip so your piece wobbles like crazy when you chuck it up. Your washers are going to end up wedge-shaped, which you don't want. You need them flat with faces parallel. Also, you need to be able to set the washer depth reasonably accurately in the jaws so that enough sticks out to allow you to face off 1mm of material without hitting the jaws.
When you finish the setup for the first one using a spider, and have it turned to size, you then set a stop or a travel indicator on the carriage or the cross slide and do the remaining 9 pieces. It takes longer to explain it than to actually do it if you have the spider. Like I say. I've used parallels (like you would use in a vise) for this purpose, and I wish I had a nickel for every time I've had to fish one or both of them out of the chip pan
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John
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John
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John Lindo
Bill in OKC too