Thread: Need setup for tailstock issue

So I just discovered the tailstock for my new dividing head has had a big miss in manufacturing.
Who knows why but they forgot to machine the seats for the locating dowels into the bottom of the tailstock body.

I'll have to try machining them myself. Not a problem if I can get it setup to do it. If you look at a BS-0 dividing head you see there is a centre drilled on each side of the head, prob where the manufacturer centres it when they made it. I'm told these centres can be used to set the tailstock tip on centre. Fair enough, I should be able to use that here too. I think I can indicate the tailstock round bar to level height and parallel to the table and find its centre axis but how to transfer that measurement when it's upside down ?

Need your ideas how to set it up on the mill if you can help please.

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Hi Phaser,

My understanding is that the slot down the bottom of the tailstock is used to align the tailstock along the slot in the machine table as well as fastening it down. You might find that the DH has a matching slot !

Originally Posted by phaser

I think I can indicate the tailstock round bar to level height and parallel to the table and find its centre axis but how to transfer that measurement when it's upside down ?

Yep do that but clamp it down on parallels to get it off the table a bit, once aligned then skim one side of the base with a side and face cutter and take note of the distance of that facing cut from the centreline of the centre.
Then when you flip it over you will have a datum and a measurement to work with.

Originally Posted by BaronJ

Hi Phaser,

My understanding is that the slot down the bottom of the tailstock is used to align the tailstock along the slot in the machine table as well as fastening it down. You might find that the DH has a matching slot !

Yes correct. and yes the dividing head has them too.

Originally Posted by shedhappens

Yep do that but clamp it down on parallels to get it off the table a bit, once aligned then skim one side of the base with a side and face cutter and take note of the distance of that facing cut from the centreline of the centre.
Then when you flip it over you will have a datum and a measurement to work with.

That sounds pretty good and I think you're on the right track but I can see problems there too.
The tailstock total height is 100mm, the base is 90mm wide and the bolt holding the centre are 80mm long. So I would need either an end mill at least 140mm long (40mm for the collet) or some other cutter more than 50mm diameter that can side cut to allow me to bring the mill down beside the tailstock. I don't have either of these.

Originally Posted by phaser

I don't have either of these.

If you have a boring head you could fly cut it, if not can you make a small fly cutter?
You will probably have to skim the top of the mounting flange also so that when
you flip it over it will sit flat on whatever you use to hold it.
Or yóu could do what i do, i dont worry about or use the keys, i align the tailstock
close to the centreline of the job with the centre in the job firm up the back bolt and nip up the front bolt
then indicate the job and tap the front of the tailstock to true the job.

Do you want to machine the recess in the base of the Tailstock so you can use those locating blocks?

Originally Posted by pipeclay

Do you want to machine the recess in the base of the Tailstock so you can use those locating blocks?

Yes.

If you remove, raise or lower the spindle block the section it sits in will be machined.

Set this up so it is square to the spindle, clamp the Tailstock down, find centre of the recess.

Put and end mill in and take a cut off both sides of the Tailstock just above the clamping bolt holes, make sure you take the same amount off both sides from the centre, once you have these machined you have a face to set up to, to machine your locating block mounts, you can even machine a surface on the mounting base to aid setup at a latter date if desired.

Once you have machined the top you will be able to calculate the correct position of your locating block slot.

No need to use a long series end mill.

Originally Posted by pipeclay

If you remove, raise or lower the spindle block the section it sits in will be machined.

Set this up so it is square to the spindle, clamp the Tailstock down, find centre of the recess.

Put and end mill in and take a cut off both sides of the Tailstock just above the clamping bolt holes, make sure you take the same amount off both sides from the centre, once you have these machined you have a face to set up to, to machine your locating block mounts, you can even machine a surface on the mounting base to aid setup at a latter date if desired.

Once you have machined the top you will be able to calculate the correct position of your locating block slot.

No need to use a long series end mill.

That sounds feasible.
I'll have a good look at that tomorrow.

What's the best cutting fluid for steel on a mill ?

I have been using Trefolex fluid which seems to be pretty good stuff for drilling tapping etc. and works well for end mills too but it's too sticky for around the milling machine and makes cleanup a pain.

I would suggest soluble oil.
If using this you may need to drill and tap for an outlet in the pocket at the end of the mill table.
You could also use a misting system.

Hi Phaser,

Originally Posted by phaser

What's the best cutting fluid for steel on a mill ?

I have been using Trefolex fluid which seems to be pretty good stuff for drilling tapping etc. and works well for end mills too but it's too sticky for around the milling machine and makes clean up a pain.

I use Trefolex paste as well ! I just paint it on with a small 1/2" paint brush, it doesn't stay sticky for long ! The heat generated when cutting, milling, drilling or turning, soon turns it to liquid. I also use Temaxol the same way. I must have had my 1Lb tins getting on for 40 odd years, and I've just run out of one of them.

I do find that you eventually get a fair bit of swarf in the tin. So what I did with it was to warm the tin in boiling water and all the swarf drops to the bottom, then tipping it to one side allows you to use a magnet to remove it.
Got another year out of the tin that way.

Originally Posted by pipeclay

I would suggest soluble oil.

Wouldn't the cutter throw that everywhere including all over me ?

I suppose it depends on where you position yourself, my answer would be no.
If the cutter is small and running high rpm reduce coolant rate, direct coolant on the job rather than cutter, use some type of shielding.