# What lathe attachment do I need?



## tjb (Jun 22, 2018)

I have a 13 x 40 lathe that will hold stock up to 1 1/2" in diameter.  I need to face a piece of 3/4" stock and a piece of 1" stock, both of which are 2+ feet long.  When I put either of them in the machine, the excessive length sticking out the back wobbles significantly.  Is there an attachment I can use to lock down the stock and eliminate the wobble?

Thanks for any advice.

Best regards,
Terry


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## Ed ke6bnl (Jun 22, 2018)

People will make an atachment for the rear of the lathe that hopefully can fit over the rear of the spindle with 4 screws around the circumference that are adjustable to center the sticking out portion of the work stock  I believe it is called a spider.


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## tjb (Jun 22, 2018)

Ed ke6bnl said:


> People will make an atachment for the rear of the lathe that hopefully can fit over the rear of the spindle with 4 screws around the circumference that are adjustable to center the sticking out portion of the work stock  I believe it is called a spider.


Thanks, Ed.

I'll do a search on that.

Regards,
Terry


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## RJSakowski (Jun 22, 2018)

For one or two pieces, I would just use three or four tapered wooden shims to center and stabilize the back end of the stock.


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## Ed ke6bnl (Jun 22, 2018)

making a spider


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## tjb (Jun 22, 2018)

Thanks, RJ.

That's a good quick-and-dirty tip to know.  I'm actually right now watching a youtube video on a guy making a spider.  Seems like it might be a good learning experience to make one.  I'll keep you posted.

Regards,
Terry


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## tjb (Jun 22, 2018)

Ed ke6bnl said:


> making a spider


Thanks, Ed.

That's actually the video I just watched!  Seems pretty straightforward.

Headed back to the shop to try and butcher a little bit of scrap metal.

Regards,
Terry


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## kd4gij (Jun 22, 2018)

Sounds like the stock is bent. I would straighten it then run it.


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## kd4gij (Jun 22, 2018)

I made plugs from Delrin  with different size wholes for my lathe.


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## tjb (Jun 22, 2018)

kd4gij said:


> I made plugs from Delrin  with different size wholes for my lathe.


Now that's a good idea.  Do they simply press in or did you make a retainer of some sort?

Regards,
Terry


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## kd4gij (Jun 22, 2018)

Just a snug fit.  I left a shoulder on the plug to pull it out..


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## tjb (Jun 22, 2018)

kd4gij said:


> Just a snug fit.  I left a shoulder on the plug to pull it out..


Thanks.  I'll try that, too.  I have a piece of scrap 2 3/4" cold rolled that I've already started milling for a lathe spider.  Seems like a pretty simple exercise, so I'll finish it.  I also have some scrap Delrin that I could use to make plugs.  I'll probably make some for the common smaller sizes (3/8" - 3/4").  Thanks for the tip.

Regards,
Terry


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## markba633csi (Jun 22, 2018)

The quick and dirty is to just wrap some cardboard and tape around the stock to keep it from battering around in the spindle


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## Charles Spencer (Jun 22, 2018)

I've used a support roller that I had for my table saw.  It worked for me.  It's similar to this:

https://www.amazon.com/WORKPRO-Adjustable-Pedestal-Jointers-Firewood/dp/B0761MNW7Z


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## Dabbler (Jun 22, 2018)

I did the same as *kd4gij, *but I turned mine out of wood, usually a 2 X 4, to size.  I've only needed a couple of sizes.  I regularly turn 1.375" steel , 4' long suing these wooden plugs.

I can turn 3/4 " stock uip to 3' long using a wooden plug as well...


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## P. Waller (Jun 22, 2018)

Make short spindle liners, use a piece of material (I mostly use plastic) and turn it slightly smaller then the spindle bore then bore it slightly larger then the stock and 1 1/2" long or so, drill and tap a hole through the wall. Place on stock and gently snug a set screw onto the stock.

If the wall thickness will not allow a tapped hole use a cats head setup.

This allows you to move the stock through the spindle if making multiple parts in one setup. This beats screwing around with a cats head and screws for every part.

Like so


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## Aaron_W (Jun 22, 2018)

Perhaps my inexperience speaking, but couldn't you just use your steady rest to work further down the bed so you have less material extending through the headstock? I thought that is what the steady rest was for?


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## Dabbler (Jun 22, 2018)

Aaron, it just takes much more time to set up your steady rest  than gripping in your 3-jaw and going for it.  all your are doing is reducing the 'whipping effect by using a plug. I think I've needed 3 or 4 plugs in 38 years, and they each took about 5 minutes to make.


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## P. Waller (Jun 22, 2018)

Aaron_W said:


> Perhaps my inexperience speaking, but couldn't you just use your steady rest to work further down the bed so you have less material extending through the headstock? I thought that is what the steady rest was for?



Setting up a steady would be silly if all one needs to do is stabilize material that fits through the spindle bore, if the work will not pass through the spindle a steady is the only option.

As an example this part would not fit through the spindle so I had to use a steady to turn the section that was welded for repair. I also made a center plug for the bore in the end and used a live center in tail stock.

It turned out reasonably well considering the amount of weld that they put on it.
3.147" is 79.93 MM for an 80 MM bearing fit. The material is 304/316 stainless, the Customer was not sure.


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## tjb (Jun 22, 2018)

Sounds like there's definitely more than one way to skin this cat.  Thanks for all the answers and great ideas.

Regards,
Terry


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## epanzella (Jun 22, 2018)

For a quick job I stuff some paper towels around a long shaft to stop wobble. That said it seems odd the 3/4 and 1 inch shafting only 2 ft long would flex enough to be a problem.


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## savarin (Jun 22, 2018)

I have used bicycle cables looped over the length sticking out and pinned to the wall and ceiling as guy ropes, a splash of oil where they touch the shaft and it spins with no wobble.
I find this particularly useful with thin stock


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## tjb (Jun 23, 2018)

epanzella said:


> For a quick job I stuff some paper towels around a long shaft to stop wobble. That said it seems odd the 3/4 and 1 inch shafting only 2 ft long would flex enough to be a problem.



Actually, it may not be a problem for the immediate project I'm working on.  There is definite wobbling, but maybe not significant enough to cause a problem.

I have rarely work with anything longer than about 2 or 2 and a half feet, but several weeks ago, I had a longer piece of 1/2" stock in the lathe.  I was facing the end when all of a sudden, the lathe starts wobbling and making a racket that sounded like a helicopter about to lift off.  I slammed the lathe emergency button and went around to the outboard side.  The stock had bent to 45 degrees about a foot out from the end.  Luckily, nothing (and no one) was in the path of destruction when the flailing began, but now I'm a little gun shy.  To me, this is a win-win:  Getting some wise counsel from experts on how to avoid a catastrophe, and a learning exercise on how to make a useful lathe attachment.

Regards,
Terry


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## HMF (Jun 23, 2018)

By the way, I want to remind everyone that we have our own VIDEO library where you can post videos without using YouTube:

*https://www.hobby-machinist.com/gallery/categories/member-video-channels.6/*


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## 12bolts (Jun 23, 2018)

Place a suitable sized sawhorse or similar near the end of your stock Nail or screw a couple of blocks of wood to cradle and bridge over the stock. Away you go.


kd4gij said:


> Sounds like the stock is bent. I would straighten it then run it.


Straight or not, excess stock protruding from the rear of the spindle will wobble. It is necessary to restrain it.


savarin said:


> I have used bicycle cables looped over the length sticking out and pinned to the wall and ceiling as guy ropes, a splash of oil where they touch the shaft......


Charles' method is also effective

Cheers Phil


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## tjb (Jun 23, 2018)

kd4gij said:


> Sounds like the stock is bent. I would straighten it then run it.


No, the stock's not bent.  See my post above on the near train wreck I had with a longer piece of 1/2" stock.  These two pieces are a. shorter than that one, and b. only 'wobbling'.  My main objective is to learn what's available out there to avoid another potential train wreck before it happens.  I just finished milling the blank for a spider.  If all goes well, tomorrow I'll drill and tap for the set screws, then try it out.

Next project will be to make some Delrin plugs like you suggested.

Regards,
Terry


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## epanzella (Jun 23, 2018)

tjb said:


> No, the stock's not bent.  See my post above on the near train wreck I had with a longer piece of 1/2" stock.  These two pieces are a. shorter than that one, and b. only 'wobbling'.  My main objective is to learn what's available out there to avoid another potential train wreck before it happens.  I just finished milling the blank for a spider.  If all goes well, tomorrow I'll drill and tap for the set screws, then try it out.
> 
> Next project will be to make some Delrin plugs like you suggested.
> 
> ...


Sounds like you're on the right track with the spider. Remember any fixed plugs you make will only work with a specific diameter rod whereas the spider will work with anything that fits thru the headstock and is long enough to reach it.


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## kd4gij (Jun 23, 2018)

2" boat shaft 14ft long.


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## tjb (Jun 23, 2018)

epanzella said:


> Sounds like you're on the right track with the spider. Remember any fixed plugs you make will only work with a specific diameter rod whereas the spider will work with anything that fits thru the headstock and is long enough to reach it.


Got it.  Thanks.

Regards,
Terry


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## tjb (Jun 23, 2018)

kd4gij said:


> 2" boat shaft 14ft long.
> 
> View attachment 270392


Now, that's big!  Not sure, but I'm guessing you used something a little more substantial than a Delrin plug on that one.

Regards,
Terry


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## Aaron_W (Jun 23, 2018)

Dabbler said:


> Aaron, it just takes much more time to set up your steady rest  than gripping in your 3-jaw and going for it.  all your are doing is reducing the 'whipping effect by using a plug. I think I've needed 3 or 4 plugs in 38 years, and they each took about 5 minutes to make.




I definitely can see the advantage for multiple parts, but for just 1 or 2, I was thinking it would be easier than making a new rest for the other end.

That is why I'm here though, to learn from those who have done it vs just a theory of how things work.


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## kd4gij (Jun 23, 2018)

The lathe is 20x80 gap bed with a 4" bore. The steel table behind it is 8ft long with adjustable stands with V blocks lined  with Delrin and kept coated with way oil. Once every thing is lined up and level it gets tested at low RPM . Machining is done at 300rpm and then polished at 500rpm.


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## tjb (Jun 23, 2018)

Aaron_W said:


> I definitely can see the advantage for multiple parts, but for just 1 or 2, I was thinking it would be easier than making a new rest for the other end.
> 
> That is why I'm here though, to learn from those who have done it vs just a theory of how things work.



That's a good point, Aaron.  However, in my experience, once you've done 1 or 2, chances are pretty good that you'll do 1 or 2 more some time in the future.  That makes projects for the spider or the plugs attain a little more desirable economies of scale.  Not to mention the invaluable practice gained from milling something out of leftover scrap metal or plastic.  I find that every time I fabricate a little gizmo of some sort suggested on one of these threads, one of two things happens: Either I butcher a piece of scrap that I probably would have thrown away otherwise; or I end up with a functional do-dad that periodically comes into use on a subsequent project.  In either event, I gain some much needed practice on something that just might have some useful application if I get it right.  A win-win.

Regards,
Terry


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## tjb (Jun 23, 2018)

kd4gij said:


> The lathe is 20x80 gap bed with a 4" bore. The steel table behind it is 8ft long with adjustable stands with V blocks lined  with Delrin and kept coated with way oil. Once every thing is lined up and level it gets tested at low RPM . Machining is done at 300rpm and then polished at 500rpm.


2" diameter; 14' long:  If I did the math correctly, that thing weighs right at 150 pounds.  Doubt if anybody would be using it for pole vaulting.

Regards,
Terry


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## kd4gij (Jun 23, 2018)

The shaft is aqualoy 19 stainless steel. A little more than 150lb.


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## RWanke (Jun 24, 2018)

kd4gij said:


> 2" boat shaft 14ft long.
> 
> View attachment 270392


That's a long shaft for 2". What kinda boat?


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## kd4gij (Jun 24, 2018)

I never see the boats. Shafts get dropped off at my shop.


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## P. Waller (Jun 24, 2018)

kd4gij said:


> I never see the boats. Shafts get dropped off at my shop.


Nice setup.
I often use a back rest on a smaller lathe that has a 4 screw bearing chuck that slides along the frame. It is limited to 12 Ft. lengths or so because someone put shelving in the way (-:





We have a large W&S turret lathe with a similar setup as below but it has a hydraulic cylinder that will advance the stock along the frame when unchucked, this is very handy for moving long heavy bars.


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## tjb (Jun 24, 2018)

Okay, here's the latest.  I completed the lathe spider this afternoon - in an un-air conditioned shop, thermometer reading 93, humidity reading 98, and heat index reading 108.  Lovely conditions.  Here's a short pictorial progression with commentary along the way.

The train wreck:  This is what happened a few weeks ago with 1/2" stock.  The bend occurred about a foot from the outboard.


The lathe spider before drilling and tapping, along side the cut-off from the scrap piece I used and stand-alone.





Several shots (in no particular order) of the set up to drill the four holes for set screws.  First, I horizontally mounted and indicated the rotary table; then mounted and indicated the chuck on the rotary table; then turned the assembly vertical and indicated to center; finally drilled the holes at 0, 90, 180 and 270 degrees.









Lathe spider with set screws (they're way too short but all I had).  Will order longer ones tomorrow.



Mounted with a piece of 1" stock.



Thanks to all for your sage advice.

Regards,
Terry


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## BaronJ (Aug 23, 2018)

Hi Guys,

A spider is fine for relatively short lengths of material protruding from the rear of the spindle.  You can get away with having more protruding with thicker, greater diameters.  In any event it is still dangerous practice.

The real cure to the problem is to use a tube secured on stands, so that the rod spins inside the tube and then it cannot bend and whip to cause damage and injury.  The use of a spider is intended to stop quite small diameters becoming bent in relatively large lathe bores.

The use of tubes is very common on production machinery where long lengths of relatively small diameter materials are used.  Once you get to a couple of inches "V" stands can be used, but even then if the material has a bend in it, or the risk of being bent a tube is still used.


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## Dabbler (Aug 23, 2018)

+1 to everything said above...  One quick addition:  If your material has some mass to it, say 1/2" steel, and the RPMs are high (if you are cutting with Carbide, for instance), then ensure your stands /tube/supports are tied down.  The rotation generates a tremendous energy, and if something goes wrong, it unleashes unexpectedly.  A friend with 30 years exp had his stand thrown a few feet (fortunately away from him) when the 1/2" rod bent!


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## tjb (Aug 23, 2018)

Dabbler said:


> +1 to everything said above...  One quick addition:  If your material has some mass to it, say 1/2" steel, and the RPMs are high (if you are cutting with Carbide, for instance), then ensure your stands /tube/supports are tied down.  The rotation generates a tremendous energy, and if something goes wrong, it unleashes unexpectedly.  A friend with 30 years exp had his stand thrown a few feet (fortunately away from him) when the 1/2" rod bent!



I totally agree.  Here's a section from my post #23:



tjb said:


> I have rarely work with anything longer than about 2 or 2 and a half feet, but several weeks ago, I had a longer piece of 1/2" stock in the lathe. I was facing the end when all of a sudden, the lathe starts wobbling and making a racket that sounded like a helicopter about to lift off. I slammed the lathe emergency button and went around to the outboard side. The stock had bent to 45 degrees about a foot out from the end. Luckily, nothing (and no one) was in the path of destruction when the flailing began, but now I'm a little gun shy. To me, this is a win-win: Getting some wise counsel from experts on how to avoid a catastrophe, and a learning exercise on how to make a useful lathe attachment.


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