Degree wheel

[Charles scozzari]

Hi, I was wondering, because I do not know and am curious as to why you would mount a bicycle/go-kart sprocket to the spindle of a lathe as a degree wheel. I see this being done by some, and what are the advantages in lathe work. Wouldn't it be easier to use the rotary table on a mill. I'm not being sarcastic, I would like to know so if there is something to be learned I would be thankful. Thanks.

 

[SLK001]

Sometimes you don't have a rotary table... or a mill. Anything that has teeth a multiple of 36 will get you mostly where you want to go.

 

[paradox_pete]

I haven't used a cog, but I have used the change gears from the lathe for indexing on the lathe. Mounted on an expanding mandrel that fits the back end of the spindle. I've found the 60 tooth gear particularly useful as one can index 2,3,4,5,6,10,12,15,20, 30 and 60 hole patterns with it. Works great. See Below...


Granted the bungee cord is a little crude, but it works.

Would I do this rather than use a rotary table or dividing head on the mill? The obvious answer is that I did not have a mill, rotary table or dividing head at the time.

There are still situations in which I might find that approach preferable. I've encountered situations where I would prefer to produce a bolt circle at a specific point in the order of operations, but would also like to keep the part on the lathe to ensure concentricity for subsequent operations....

-Pete

 

[Charles scozzari]

Sometimes you don't have a rotary table... or a mill. Anything that has teeth a multiple of 36 will get you mostly where you want to go.

Thanks for your reply. I never looked at it that way, makes sense. But I believe you would still have to remove the work from the chuck to drill the necessary holes.

 

[Charles scozzari]

I haven't used a cog, but I have used the change gears from the lathe for indexing on the lathe. Mounted on an expanding mandrel that fits the back end of the spindle. I've found the 60 tooth gear particularly useful as one can index 2,3,4,5,6,10,12,15,20, 30 and 60 hole patterns with it. Works great. See Below...
View attachment 429997

Granted the bungee cord is a little crude, but it works.

Would I do this rather than use a rotary table or dividing head on the mill? The obvious answer is that I did not have a mill, rotary table or dividing head at the time.

There are still situations in which I might find that approach preferable. I've encountered situations where I would prefer to produce a bolt circle at a specific point in the order of operations, but would also like to keep the part on the lathe to ensure concentricity for subsequent operations....

-Pete

Hello Pete, now I see what its purpose is. Thank you for your reply

 

[RJSakowski]

Thanks for your reply. I never looked at it that way, makes sense. But I believe you would still have to remove the work from the chuck to drill the necessary holes.

A tool post mounted Dremel will do nicely.

 

[Charles scozzari]

A tool post mounted Dremel will do nicely.

Thanks, that will work fine as you say. I'm just glad I received what the the use of the sprocket was.

 

[RJSakowski]

The tailstock on my Atlas Craftsman didn't have a dial so I made one by scribing the lines with a lathe tool bit. The tailstock lead scrw is 16 tpi which meant one revolution of the dial was .0625" So U needed 62 -1/2 dial marks for .001"/ division. I laid the dial out using polar graph paper (that was long before CAD, Excel, etc.), cut the dial out and glued it to suitable backing and then to the chuck face. I made an index mark and visually lined it up with the marks on the graph paper. Not as precise as using a toothed wheel and a pawl but seeing the marks were on a circle more than 4X the diameter of my dial, more than accurate enough for my purposes. I scribed the 62 full thousandth lines with every fifth line slightly longer and I stamped numbers 1 -6 on every tenth line and used the set screw for the zero mark. To make equal length lines, I used the compound rather than moving the carriage.

Back then, graph paper was the stock and trade of every science and engineering student. It has fairly well disappeared in the present day but it can be downloaded from the internet. https://print-graph-paper.com/details/polar

 

[epanzella]

I too use a sprocket dividing head on the lathe. I built it back when I didn't have a mill or rotary table but it's so convenient I still use it today. I have a drill arbor that goes in my tool post and I can run off a hole pattern by just offsetting the drill to the required radius and indexing the spindle. It uses a lead screw and a lever with a pin that engages the sprocket teeth. I have a 50 and 72 tooth sprockets that will give me just about any divisions I need. Sprockets are only about 10 bucks each and come in most every tooth count from 10 to 72.

 

[paradox_pete]

A tool post mounted Dremel will do nicely.

I don't have tool post mounted Dremel on mine (yet ).

I do have a very simple drill spindle. It consists of a boring bar holder (3/4" capacity AXA type to fit my lathe) into which I have pressed a couple of 1/2" ID Oilite shoulder bushings. The spindle is just a piece of 1/2" drill rod threaded on one end to accommodate a thread on drill chuck. A cordless drill does the turning.

My lathe came with 20, 30, 35, 39, 40, 45, 46, 50, 55, 60, 63, 65, 70, 75, 76, and 80 tooth gears. I figure that probably covers most indexing jobs I'm likely to need. As I have installed an electronic lead screw, I no longer need them for threading, etc. so this is a good use for them.