Milling Machine

[Pete.]

My 1952 Herbert has powered table feed. There's a small motor in the column driving a gearbox on the back with 3 levers for 8 feed rates. It also uses a telescoping shaft with universal joints each end as in the image above, which drives the table lead screw by a bevel gear pairing.

 

[awemawson]

No gears or change belts and an inverter drive, and I predict you will be short of low speed torque.

 

[Screwdriver]

The spindle is the very heart of the machine so it was a heart in mouth moment when I hacked off the crudely welded on extension.

So that it would fit into the press. I had covered the bearings in plastic while grinding (just in case they aren't already shot).

Then carefully grind away the weld.

Until I can see the original spindle bore.

Quite a relief to find it just popped out.

It's definitely hardened, the lathe wouldn't touch it so I had to hand grind the end on a bench grinder.

Came out lovely.

Screwd.

 

[Screwdriver]

Spindle looks nice and straight which I confirmed in the lathe.

Took it to the surface plate to measure it up.

Easy on the surface plate using a vernier.

and I use "Measures" on the iPhone to record the results.

I still don't know what the best collet type will be or how to approach the conversion. I am sure the spindle is hardened so it will be super difficult to take out the existing internal taper to suit, say, R32 collets. I would also need to mod the chuck.Another option is to simply screw on a complete adapter but I would then lose 2-3 inches of travel. What to do? And what are the BEST options for a milling machine regards costs of tooling?

I have an ex school Boxford VMC with those stubby quick change type collets. Maybe that's the way to go?

The OD at the bottom is only 31mm so there's not much room to play with. maximum of a 5/8ths inch collet I should expect.

Screwd.

 

[Shox Dr]

Could it be ground out to take a ER type collet. Machining a nut to suit. Keep the height as well

 

[Screwdriver]

Could it be ground out to take a ER type collet. Machining a nut to suit. Keep the height as well

It's looking that way. despite nominally having the right equipment and potentially the skill to do it myself, I would have to send it away to be ground properly! Incidentally can anyone recommend a place (ideally in/near London) that would take on a small job like this?

I'm half hoping it might at least have a standard thread I might find an R32 collet closing nut to fit. Haven't measured the thread yet tho.

S.

 

[penfold]

if you put up a dimensioned sketch of the spindle the combined heads could have a scratch about ways forward.

 

[Screwdriver]

This is it.

The collet dimensions approximate the internal size of the taper. Haven't yet measured the threads shown in grey. Collet included taper angle is about 23 degrees.

S.

 

[ukracer]

This is it.





The collet dimensions approximate the internal size of the taper. Haven't yet measured the threads shown in grey. Collet included taper angle is about 23 degrees.

S.

what are you using to draw that??

 

[Screwdriver]

what are you using to draw that??

Sketchup. I use it for all sorts of things. Workshop layout, design and construction or just seeing if something will fit.

Here's a simple stand designed this way which I later used to buy a suitably sized angle box off eBay.

S.

 

[Screwdriver]

This is it.

S.

Collet closing thread is 11 tpi, 1 3/8th" dia.

Spindle retaining thread is 16 tpi, 15/16th" dia.

s.

 

[Screwdriver]

Looks like ER32 won't fit on the existing shaft unless I build it up. Maybe ER25....

S.

 

[penfold]

At risk of repeating myself, modify an ER32 chuck and a drawbar to hold it in there, then go milling.

 

[Screwdriver]

At risk of repeating myself, modify an ER32 chuck and a drawbar to hold it in there, then go milling.

I appreciate the sentiment but at the moment the machine is a pile of parts. It will take a fair bit of effort to rebuild it, let alone restore it so it is worth spending some time solving this problem with the least amount of compromise on height, rigidity and accuracy.

In the grand scheme of things, pontificating over the choice of spindle solution is a blink of an eye. Plus I can do it sitting here watching the telly. The rest of the build/restore will be the grimy practical stuff that I will need to "just get on with".

 

[penfold]

It just seems easier than modifying what you've got and cheaper/easier than making a whole new spindle. Whatever solution you choose.

 

[Screwdriver]

Sometimes the journey is more important than the destination.

 

[atconut]

are you sure it's all one piece. it's hard to tell from the pics but it looks like theres a locking ring. does the ring with four holes in it unscrew, it may be some kind of collet chuck. i could be wrong but have a close look around that ring it may split. the steel looks a different colour

 

[atconut]

I'm sick of looking for one having been searching basically for years! So I snapped this one up for a pretty penny. Paid too much TBH but it's small enough, cheap enough and just up the road. Looks like this:

Needs work to rig up a decent motor solution, in fact it needs quite a lot of work now that it looks more like this!

Full info here: http://www.lathes.co.uk/taylormiller/

It's small but chunky, should easily be able to squeeze it into a corner. Might take a while to get it going again tho, I am now staring at a quarter ton of scrap.

Which I hope to make into something like this:

Close up of the OEM collet. I think it's a proprietary type, I'll know better when I whip the spindle out.

Does anyone recognise that type of collet and know where I might find some. Also would be great if anyone had some spare cutters to get me going.

S.

take a close look just above the thread it looks to me like there is a joint there. i bet that comes out maybe held in by the locking nut (ring)

 

[Screwdriver]

are you sure it's all one piece. it's hard to tell from the pics but it looks like theres a locking ring. does the ring with four holes in it unscrew, it may be some kind of collet chuck. i could be wrong but have a close look around that ring it may split. the steel looks a different colour

It does look like a split but it isn't. The steel is blackened from the hardening process (I assume) the spindle is a different colour where it has been ground.

take a close look just above the thread it looks to me like there is a joint there. i bet that comes out maybe held in by the locking nut (ring)

You mean as if I haven't already had a close look? How much do you want to bet...

 

[Kram]

It's definitely hardened, the lathe wouldn't touch it so I had to hand grind the end on a bench grinder.

It will, you just need carbide cutters. I have turned HSS blanks into swarf easy. I needed accurate angles for a TR2 threading tool so turned it.

Good drawings. Looks easy enough to copy.