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Carld
01-26-2010, 03:58 PM
:D Well, I cut the thread today and I decided to do an under cut and thread to the shoulder. It worked great and I used the 1.5mm because my pitch gage didn't show daylight in the thread. BTW Tiffie I do have a 1.6 and other odd thread settings on my lathe. Here is a photo after the second pass.

http://i82.photobucket.com/albums/j276/yeathatshim/P1260005.jpg

Well, when I got to where I thought it should be I started removing the part and testing. After a few cuts and tries I said, Hmmm. Then I started looking at my thread and the spindle thread, :eek: the spindle is left hand and I cut a right hand. Geez, bummer, bah humbug.

Lets stop and think, I'll turn the thread off and slip it in the spindle. Ahhh, that works just fine thank you.

Man I hate left hand threads. This has happened before, but I didn't get mad and throw things this time. Maybe old age has made me mellow :rolleyes: . I used to keep four of five spare ceramic coffee cups at work because when something went really wrong I would pick the cup up and smash it on the floor. Umm, did I ever tell you about my very bad temper, oh well.

I saved all the figuring that Tiffie and I did and put it in my lathe manual folder and someday I may make a spider that screws in the spindle. Lets see now, I have had the lathe since 1991 or 1992 and have only needed a spider once. Heck, I may die before I use the one I just made.

I keep a folder on every tool I have in the shop. Sometimes I think I keep to many records and files.

Carld
01-26-2010, 10:52 PM
I've been thinking about this screw up and I think I will make a threaded part to put in where I cut the wrong thread. It will be easier to thread from left to right if a big shoulder isn't in the way and I can bore the big part out insert the new threaded part, locktite and pin it and it will be like new and I am the only one that will know it was a mistake. I may not even pin it because the locktite I use is high strength/high temp. I could even shrink fit it.

Uhhh, that is, except anyone that looks at this thread. A carpenter friend told me once good carpenters can cover their mistakes and I always try to apply that to doing machine work.

Doozer
01-26-2010, 11:17 PM
"Man I hate left hand threads."

Usually left hand threads are the easiest to cut,
because you start in the groove and cut away
from the chuck, ending the cut in air.
No critical stopping.

--Doozer

Boucher
01-26-2010, 11:19 PM
There have been several that recommended turning a threading tool upside down and reversing the spindle to turn a right hand thread outward from a sholder like that. Well it took me a while to get an upside down threading tool on center. Turned some threads yesterday using this process. The fly in the ointment is that you have to remember to reverse the spindel. I kept finding that I wanted to flip the aporn control lever up in the normal mode. Old habbits are hard to break.

About the time you get good at making external threads change to internal and now you have to wind the cross slide in rather than out. I don't think that I will ever live long enough to get where this comes naturally.

Black_Moons
01-27-2010, 01:11 AM
lol! tell me about it.. ok I need to crank, uhh, 3 turns in... and thats in out not out in... I mean.. err.... ok just crank it.. DAMNIT wrong way.. now how am I gotta fix that gouge?

beanbag
01-27-2010, 01:17 AM
just remember to turn the compound -29 deg

oldtiffie
01-27-2010, 02:01 AM
I've been thinking about this screw up and I think I will make a threaded part to put in where I cut the wrong thread. It will be easier to thread from left to right if a big shoulder isn't in the way and I can bore the big part out insert the new threaded part, locktite and pin it and it will be like new and I am the only one that will know it was a mistake. I may not even pin it because the locktite I use is high strength/high temp. I could even shrink fit it.

Uhhh, that is, except anyone that looks at this thread. A carpenter friend told me once good carpenters can cover their mistakes and I always try to apply that to doing machine work.

Carl.

If it were me, I'd just machine a shallow groove in the (previously) threaded section about ~ 1/32" wide and deep and bend a bit of "springy wire" to be just a bit bigger than the screwed section. Use it as a "circlip" and just "spring " it closed as you feed it into the tail-stock.

Wind on a couple of turns of "Teflon" tape.

Either will hold in.

I've never bothered to make a spider as I just get a bit of timber and turn a flanged and plain section (neat fit in my lathe spindle bore) and a hole that is a fairly neat fit on what-ever I want to hold with the spider.

I smother oil or grease onto the spigot and drilled hole and then I get my BFH and knock the spider into the spindle bore.

(The BFH is just "tapped" - delicately - like a "Fairy's kiss" - as you can imagine).

Never a problem. I just push/punch it out from the chuck end (more BFH work).

If I need a spider away from the lathe, I just stand a bit of timber up in a clamp that I have and drill a hole ("by eye" with a portable drill) - "adjust" as necessary and I am set to go.

I had a bit of "plastic" that I turned to be about 0.010" smaller than my spindle bore. I also turned a groove and fitted an "O" ring to it. It was ideal for keep grunge out of the back of my chucks and spindle. I think it got buried under the shade tree when it was used for "me-kan-e-k'n".

I had a similar one I made from wood that I drilled to suit when I needed to support thin stuff that was to be run at high speed but did not reach the back of my lathe spindle. That one too was smothered in oil/grease as before.

"Hi-tech" external "spider-holders" are here - just "adjust" as necessary (all are "tri-pods) - and if they move, drop a bag of sand or gravel onto each leg - works fine:
http://i200.photobucket.com/albums/aa294/oldtiffie/Triton/Weld_earth6.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Triton/Weld_earth8.jpg


I could even shrink fit it.

Uhhh, that is, except anyone that looks at this thread.

The day I have to "explain" or worse - apologise - to anyone else for something that suits me in my shop is the last time one of us will be in that shop.


A carpenter friend told me once good carpenters can cover their mistakes and I always try to apply that to doing machine work.

Most Carpenters and Painters I know tell me that's left to the Painter.

Gotta "keep up standards" here.

Carld
01-28-2010, 12:22 AM
Good thoughts here abot this problem. I went on a trip to Atlanta Georgia today with a friend and on the way solved two problems.

1--I will make a sleeve to press in the spider with the correct threads.

2--for bending some tubing for a customer I will make a custom tubing bender just for that application if they want to pay for it. Other wise the deal is off.

That's 14 hours of riding along on the trip to work it all out. I machined both parts in my mind so now I have to machine them for real.

Cutting a left hand thread imperial is easy. Not stopping to really be sure whether your supposed to make a left or right is the problem. I thought right and it was really left. Your cutting from the head stock toward the tail stock so you don't have to have the tool upside down, just reverse the spindle direction.

Tiffie, at work we machined a piece of wood or plastic to fit the spindle bore and a hole for the rod to fit through or just stuffed a rag around the bar in the spindle.

I want to do some rifle barrels and I want a spider that is screwed in the bore and as accurate as I can get it. Ordinarily I still use a rag because it is fast and adjustable. We also had a stand with two roller ball bearings forming a V for a shaft to lay in and that worked great for most work. If I need one I will build it and not a day sooner.

oldtiffie
01-28-2010, 12:47 AM
Thanks Carl.

Good stuff.

I forgot about the "4-jaw accuracy" required for "Gun-smith" work - in the US (have guns) where-as there's very little of that here as gun-ownership (and I suspect Gun-smithing too) is very tightly controlled and regulated here.

Glenn Wegman
01-28-2010, 05:58 AM
I use a collet closer quite often, so the adapter is on the spindle end making it difficult to use a spider.

I just turn O-ringed bushings that plug into the adapter to center stock.

I also have bushings that plug into the collet closer itself.

http://img.photobucket.com/albums/v647/Fighter1/PB080784.jpg

Much simpler than a spider anyway and they don't leave any marks on the stock....

You could even O-ring the ID in the case of a gun barrel.

Doozer
01-28-2010, 08:40 AM
Glenn- Where I used to work I had a Nardini.
Would like to own one myself one day.
Lucky dog!
Oh, like the bushing idea.
--Doozer

Glenn Wegman
01-28-2010, 08:53 AM
Doozer,

What a GREAT machine!

I look for excuses to run it :)

Carld
01-28-2010, 01:48 PM
:eek: Ohhh, great idea, the Oring would hold the bushing in and help keep the bushing centered as well. I like that.

Boucher
01-28-2010, 02:56 PM
Carl:
Not to nit pick but for correctness. For Left hand threads you reverse the feed direction not the spindel direction. For Right hand threads for feed from left to right you reverse the spindel direction with the tool upside down. When you develop conditioned reactions like lifting the feed lever for normal turning and you fail to reverse the spindel direction it is one of those uh-oh moments.

I have a Quick closer like yours that came with my lathe but was never mounted. I just adapted the tube to a hand wheel type. Sometime when you have it installed post a picture.

For barrell work most bushings are made adjustable with four brass tipped screws like a four jaw chuck. Since there is no relative movement as they are turning with the work they do not mar it.

I like your o-ringed bushings.

pcarpenter
01-28-2010, 06:20 PM
The outboard spindle bushing idea got my brain to actually thinking about something other than work. I have seen outboard mounted chuck fixtures....how about a 5C collet closer arrangement for that end....something that threads onto the outside spindle threads (for those that have them) and has a ring to close the collet sort of like the Jacobs rubber collet spindle chucks?

As pointed out though..for barrel work, and some other stuff, the spider is for a bit more precise workholding and not just to keep the tail from whipping, so the ability to adjust for zero runout on that end still makes them necessary for this function.

Paul

oldtiffie
01-28-2010, 07:02 PM
An adjustable spider is only a variation of the principal of a 4-jaw chuck (or even a 3-jaw) - and I've seen pics or read of lathes (usually but not exclusively) big ones with a chuck on the rear end of the lathe spindle.

Carld
01-28-2010, 08:29 PM
Boucher, your right, I wasn't thinking straight. I will start from the left and thread right so I still turn the chuck CCW like normal:o . I don't have a quick closer though, that's a photo of Glenn's.

Paul, a 3 jaw chuck on the left end of the spindle would be handy. The lathe that Tiffie is talking about is called a pipe lathe. The last shop I worked when I retired had one and It had a 4 jaw chuck on both sides of the head stock. It had a 12" hole through the spindle and was real handy for big work. It was somewhat of a bugger to dial in both ends of a shaft though. The biggest problem with that lathe is it did not have a neutral where the chuck could be turned freely. We put it in the lowest gear and carefully used the clutch to rotate the chuck. It was a big old Lodge and Shipley.

Glenn Wegman
02-02-2010, 05:59 PM
I have a Quick closer like yours that came with my lathe but was never mounted. I just adapted the tube to a hand wheel type. Sometime when you have it installed post a picture.
.

http://img.photobucket.com/albums/v647/Fighter1/Closer.jpg

http://img.photobucket.com/albums/v647/Fighter1/Closer1.jpg