making a spider on lathe spindle

foreign

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Joined
Jun 26, 2008
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424
Location
christchurch, nz
I have a question to folks. How did you make the spider on your spindle? If you have a short spindle sticking out the left of the lathe then you can make a slip fit spider and then that is relatively easy. But the length of my spindle sticking out after i remove my safety cover is about 5". If i could put my screws near the bearing then i can do shorter barrels

so the way i was thinking was to make a "guide out of aluminium and then hand drill through it to guide the drill. Wondering if people have other ideas?

How did you do yours? Obviously i want the screws 90 degrees to each other and meeting square in the center.

Cheers
 

Hired Gun

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Joined
Apr 21, 2003
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1,561
Location
North Bend, Oregon
I made a .001" slip fit collar / guide to slide over the smooth outboard spindle. I left it 1/2" thick and taped it using a rotary table on the mill. I drilled down through the guide with a mag drill sitting op top of the gearbox. Then the threads worked as a tap guide to keep the tap running true. I then left the collar in pace to give me additional strength otherwise it only takes very little pressure to distort the spindle tube and wear the precious spindle bearing unevenly. All done my nearly sharpened brass tip screws meet perfectly across from each other. It looks very factory.
 

Clark

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Joined
Oct 19, 2006
Messages
746


If you type "lathe spider" into google images, you will see many lathe spiders, 4 or 5 of them I built.
What got me started was Roy of RVB precision in 2000 on the old yahoo gunsmith forum talking about it. I asked him for a pic and he took this one and posted it.
http://rvbprecision.com/
That pic is 15 years old.

All the ones I have made have 4 jaws, not 3.
I have put them on Jet, Clausing, Atlas, and Precision Matthews lathes.
 

J E Custom

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Joined
Jul 29, 2004
Messages
10,510
Location
Texas
I have a question to folks. How did you make the spider on your spindle? If you have a short spindle sticking out the left of the lathe then you can make a slip fit spider and then that is relatively easy. But the length of my spindle sticking out after i remove my safety cover is about 5". If i could put my screws near the bearing then i can do shorter barrels

so the way i was thinking was to make a "guide out of aluminium and then hand drill through it to guide the drill. Wondering if people have other ideas?

How did you do yours? Obviously i want the screws 90 degrees to each other and meeting square in the center.

Cheers
I recommend making the spider as short as you can. If you remove the cover and it will allow you to work shorter barrels you can cut the spindle back some. I know a smith that did this and it works well. it was a little trouble to cut and protect the gears from the cuttings but it did not change the operation of the lathe without the spider and with the cover replaced.

My Lathe had the bearing close to the cover so I couldn't cut mine or I would have.

Some spindles are threaded on the inside and some are on the outside, mine is threaded on the inside so I made the spider slip fit the outside to save the bore diameter and the overall length of the spider. it fits very close to the cover and the reinforced ring that holds the adjusting screws is only 1/2" wide and has 4 socket head screws for clearance and ease of adjusting with a long Allen
wrench.

I first tried brass screws (To prevent marking finished barrels/work) and found that they still made marks, so I switch to using a brass/or aluminum split bushing and let the screws mark that.
I later switched to the socket head screws for ease of adjustment and have not changed it since.

My cover is also Aluminum so I attached a steel plate to it for the magnetic base on my dial indicator for centering the work.

I use the spider often and could not do precision work without it. So build it very precise and you will come to depend on it. I also tried a three screw version and found it to be difficult to
center work increasing setup time.

J E CUSTOM
 

Stob

Member
Joined
Jun 1, 2015
Messages
13
Location
Virginia
I agree with JE's comments, make it as short as possible to the spindle. I keep my cover on, but it has a depression down around the spindle, so it works. I made mine with the same ID as the lathe spindle. I use a 4 jaw chambering, and use 4 screws in the spider, and align them with each other. Tome it makes dialing in easier. The same can be applied if using a set-true, tey use 4 adjustment screws too. I made 4 copper tabs to protect the barrel from the screws. I simply cut a piece of 3/4" copper pipe, split it two ways, then bent a tab to hold them. I slip them in the spider between barrel and screws. It's easier for me since turning the barrel around the barrel diameter is different to use a sleeve. But whatever works for you.
 

Clark

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Joined
Oct 19, 2006
Messages
746
I use 5/16-24 bolts on the spider. I put brass tips on the ends by annealing and drilling and tapping for 6-32 brass screws.

On the other side of the headstock, I put a gimble Copper wrap of wire on the breech with the 6 jaw, and then dial in the spud with the set thru on the chuck. Of course, the big deal is having the spud dial in at more than one spot, so the chamber will be parallel with the lathe spindle.
 

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