Sixis 101 House Mill

[Jasonb]

Jo the disadvantage of all that bearing surface is it adds to the height of the setup when used with the work sticking upwards so its good in some ways not in others, plus if you wanted to use the versatile vertically you would have to cobble together with an angle plate which would flex even more

Your last comment about loads on the tables bearings would only apply when cutting curves most of the time the table would be locked to the base so no load on the bearings. Also any downwards pressure would tend to push teh table against the base so the red area you showed in the L/H image would still come into play when used as in teh R/H

Rod, yes its usual to have the flutes run at a slightly different angle to the column surface.

[Jo]

Jo the disadvantage of all that bearing surface is it adds to the height of the setup when used with the work sticking upwards so its good in some ways not in others, plus if you wanted to use the versatile vertically you would have to cobble together with an angle plate which would flex even more

I personally use a 8" rotary tables when working the other way round normally the one on the  BCA which has a zero height addition.

But of course Sexy  will be getting his tilting table which is designed to mount the VDH with its nose level with where the top of the standard table is.

Jo

[Allen Smithee]

Everyone knows that the Myford Super 7 is the perfect lathe 

I am selling mine 

I'm certainly hoping that the S7 is the perfect lathe, 'cos by strange a coincidence (that isn't really a coincidence) I'm buying one.

Mind you, even a Clarke CL300 or a Unimat 1 would probably be a more effective than my existing lathe...

AS

[steamer]

Just a tease Jo - just a tease 

  I know you are a one lathe man Tug

I am still looking for my perfect one 

Jo

Everyone knows that the Myford Super 7 is the perfect lathe 

Naw.....South Bend 9A......loaded.....

[Jo]

  Ok I need a pair of nuts, the words and music says they should have an internal thread of 1" by 24tpi and 1 1/16" by 24tpi, which does not match any std threads. Reading my Zeus tables 24 tpi threads seem to have a depth of 0.02556", so in real numbers = 0.65mm. A thread of 1mm  pitch would have a depth of 0.61mm, so that 24 tpi number seems about right 

So I guess I need two bores:

25.4- (2* 0.65) = 24.1mm

27- (2 * 0.65) = 25.7mm

  Is that right ? I reserve the right to attempt a 1mm pitch thread if I find it difficult to set up the change wheels on which ever lathe I choose to use to do this on 

Jo

[Jasonb]

Depends on your chosen thread form to some extent, also if you are using those indexable tools are they part or full form? A HSS tool ground to a point will have to go in deeper than a full form tool with a rounded tip

[Jo]

Depends on your chosen thread form to some extent, also if you are using those indexable tools are they part or full form?

Yes using the tools but no idea on the form

Jo

[steamer]

Unified has a flat at the tip equal to 1/8 the pitch.     Don't recall metric off the top of my head.


Dave

[Jo]

The threading tool has a radiused tip rather than sharp and as I have a matched pair of these thread cutting tools I will assume that I should be able to cut matching threads 

I have taken off an extra 0.1mm on the bore to allow for that radiused tip.

Jo

[Jasonb]

Tubal Cain gives the minor diameter for a nut as D - 1.082P

So your M25.1 x 1 would need the hole 24.318 as the crests are flat

and the M27 x 1 would need the hole 25.918

If using a pointed tool then your depth of cut would be 0.65mm but as your tips will have some rounding to the tip its more likely to be in the region of 0.6mm. Thats assuming your tips are suitable for 1.0mm pitch, the larger pitch range partial profile will have too big a radius.

J

[Jo]

As my Prazimat has a metric leadscrew I would have the wind the tool in and out each time so 24 TPI or 25.4 tpi makes no difference as long as they match (I hope) So using one tipped threading tool and taking very shallow cuts using the mandrel handle:



A thread slowly emerged 



Then off to my larger  dividing head to mill and drill the tommy bar holes and the grub screw holes:



The final stage being to part off and counterbore the back for a short distance leaving 6.35mm of thread



So now I have two nice nuts and next is to play with my spindle. So near, so near 

Jo

[Tennessee Whiskey]

Sounds like a great evening for you, a nice spindle with two nuts  .

Big E

[Jo]

Hi Big E 

The spindle is next, maybe for this evening. And then we can see how awful my first ever attempt at thread cutting was 

But I might get side tracked fondling some castings 

Jo

[Jasonb]

I wonder how well suited these tips are to hand turning the work? it looks a bit torn rather than cut, some cutting fluid may have helped.

Are you going to do a test male thread or risk the whole spindle?

[Jo]

That is not a bad idea  I was going to start by turning up the basic spindle shape then add the thread as an after thought.

Jo