My second dumb question...

[Chris333]

Ok I am making a crankshaft from 3/8" steel. The end of it needs to be turned down to 1/16", the plans say once you get down to 1/8" to support the end with the tail stock. Well how do I do that?

The orange marks show the travel I would need back and forth so the tail stock is as far left as it can go and fully extended.

I'm sure this is a simple thing, but I can't figure it out.

Thanks
Chris

 

[joe d]

Hi Chris

Quick and dirty: chuck a 3-4" length of 3/16" drill rod, turn a point on the end of it, then put a drill chuck on the tail-stock ram with your temporary dead centre in it... here's a picture:

Then, like me, you can add "building a extra-long tailstock ram" to the "to-do" list :big:

Hope it helps, Joe

 

[hammers-n-nails]

im noexpert but my first thought would be to make a shaft of any convenitent diameter, turn a point on it the same angle as the center on one end and center drill it on the other, it would be like a live center extention. then support the extension with your steady or make something to bolt to your table. i dont see any reason why that wouldnt work. others will probably have better ideas.

 

[Blogwitch]

Chris,

The chappie who did the plans and instructions certainly never used your size of lathe. I sometimes have the same sorts of problems on my large lathe when working with thin items on the faceplate. I use the centre for locaction when setting up. I got around it by making an extended rotating centre, but I am lucky in that mine is a lot beefier machine than yours, I don't think you could do that and still retain rigidity.

In a situation like yours, where you can't support the end of the job, normally, you would speed up your spindle in an attempt to get the job to be more rigid by using centrifugal force, then taking lighter cuts to prevent deflection on the component end. You have the advantage that your little machine should be able to get up to a higher speed than your average larger machine.

Sometimes, things like this have to be a compromise between correct machining practices and getting the job done.

Hope this helps

Blogs

 

[hobby]

Hi Chris

Quick and dirty: chuck a 3-4" length of 3/16" drill rod, turn a point on the end of it, then put a drill chuck on the tail-stock ram with your temporary dead centre in it...

Nice idea.
I need to remember that too...

 

[hammers-n-nails]

joe must have jumped in front of me, please ignore my idea his is much better. blogs might work too never tried it.

 

[kcmillin]

Chris, I may have a solution. Although I am no expert, and I have never tried this.
Bring the work to the center.
heres how,
Can you put a center hole on the end of the shaft that is currently pictured in the chuck? If so, you can take a larger round peice of steel, place it in the chuck and leave enough room between your tailstock and the peice of steel. Then turn a 60 degree cone to act like a center in the lathe, without removing it, place your shaft between the two centers and drive the peice using a lath dog. (I have never used a lathe dog)

This is just like turning between centers, but with the center extended.


hope this helps

Kel

 

[joe d]

Chris

If you haven't found this yet, look over Dean's mods for his Taig lathe... some really nice work there, he's increased my project list enormously.
http://www.deansphotographica.com/machining/projects/deadcenter/deadcenter.html

Joe

 

[Chris333]

Excellent!!! Joe's idea seems to work for me:

Maybe one day I can answer instead of ask...

Thanks everybody!

 

[Deanofid]

Way to go, Chris.
Good suggestion, Joe, (and everyone!)

Dean

 

[SAM in LA]

Chris,

Remember that you can mount your tool post to the T slot on the right side of the carriage. That will allow you to position the carriage closer to the chuck and allow the tail stock to be closer too.

SAM

 

[Chris333]

In my last photo if I had the tool post in the other slot then the carriage would hit the jaws of the chuck. but that idea did work in another situation.