Lathe Toolpost Cutting/Grinding Spindles

[Antman]

Hello again after a long absence from posting, only lurking,

I haven’t even had much shop time in the last 2 months due to sonnydoes (for my old Mom) daddydoes and honeydoes, also life has kinda been getting in the way of my hobby. Well I have been machining (my description) for 2 years now and I don’t yet have an engine to show for it, nor even plans for one (but I will get there). I have been having fun making tooling.

I’ve been thinking of toolpost spindles and one of my kids bought me Harprit Sandhu’s book, “Spindles” which has good info on their construction but little on their use. To my way of thinking ( I am a completely self taught “machinist” … I have only watched experienced machinists about 3 times in my life for a total of about 10 minutes so know where my ideas are coming from) there seem to be many advantages for a variety of operations like slitting colletts, gear cutting, drilling radially etc etc for milling spindles in the lathe. Advantages like easy setting of centre height, getting subsequent operations square and concentric and the prospect of easy indexing using the lathe’s change gears.

However, I have not seen much use of toolpost spindles in the HMEM build logs. Perhaps disadvantages and impracticalities outweigh what I think are the good reasons to use spindles. I see that industrial CNC operations can have workpieces and tools on all sorts of axes.

The first spindle I want to make is a cutting frame and its first job is to split a collett thingy I’m thinking of.

Just curious,
Cheers,
Ant

 

[arnoldb]

Hi Ant

Like you, I have had a lot of fun making tooling, and for about the same amount of time. So far, I have not had a real need for toolpost spindles; on the odd occasion where those might have been useful, I found work-arounds.

What I did find very useful was a means of indexing and mounting workpieces on the cross slide - for building my first engines and a lot of tools - to do basic milling operations on those. I was fortunate in that I had a dividing head and vertical slide for my lathe - I just had to learn to use those. So if you're looking at useful tools to make, I would highly recommend something along these lines. It's not difficult to make an indexing mechanism to use your change gears (IMHO you don't need a super accurate dividing head to start off with), and with a bit of effort I'm sure you can make your own vertical slide as well if you don't yet have one.

Seeing as you're relatively close by, I think I can help you with engine plans as well; if you'd like that, just pop me a PM

Kind regards, Arnold

 

[Joachim Steinke]

Hi Ant

To my opinion tool post spindles are very useful on the lathe, even though you might have a regular milling machine in your shop. And you can save a lot of time, especially with small but complex parts which will require additional dividing operations.

Milling and dividing on the lathe is an old but still very common watchmaker technique which finds its continuance in our modern lathe based CNC machining centres which normally contain a lot of driven extra tooling.

Leaving things right there at the lathe and inside the chuck can be very advantageous: You don’t need to shift the pre turned parts over to your mill, you don’t have to rig a dividing head on the mill table and you don’t have to make extra centring efforts. And you are able to do extra turning operations in between all the milling and drilling jobs, and that without loosing the centring of your workpiece.

But you will need a dividing attachment for your lathes main spindle, without that it won’t make too much sense.

Here is a nice example of a watchmaker using his tool post attachment, you don’t need to understand the French text (nor do I…ha ha ha….), the pictures are self explaining:

http://www.horlogerie-suisse.com/forum/viewtopic.php?f=2&t=15628&start=30

Building this special geared wheel for instance, would be much more complicated with the inclusion of a milling machine.

And if you don’t mind my German writing you might have a look at my own site too, here are some articles concerning tool post spindles and dividing on the lathe:

http://www.metallmodellbau.de/Teilen_auf_der_Drehmaschine.php

http://www.metallmodellbau.de/Angetriebene_Werkzeuge_auf_der_Drehmaschine.php

And this is a newer version of my grinding spindles which of course can be used as a light milling and drilling spindle as well.

http://www.homemodelenginemachinist.com/index.php?topic=11371.0

Achim

 

[steamer]

Hello Achim,

I too am planning a small spindle for my small lathe. I will be using the Headstock spindle from a WW lathe, but with a new housing to fit my AXA toolpost. It will take 8mm collets.

These spindles are very inexpensive on ebay and are very durable with a little care. Though not good for say 20000 rpm, they stand up to 4000 rpm just fine which will cover all my work.

Dave

 

[Joachim Steinke]

Hallo Dave

I believe using a small headstock for a spindle base is a good idea if you have a machine that’s big enough to carry this extra load and has the required working space around the tool post and between the centres as well.

Another nice but commercial layout is the Quick Step milling attachment from Hemingway:

http://www.hemingwaykits.com/acatalog/The_Quick_Step_Mill__.html

My own equipment is really small, let’s say one size larger than the usual watchmaker machinery. The lathe has a distance between centres of 14” and a centre height of 3”, under that circumstances “normal sized” attachments will not fit. That is the reason for developing my own spindle attachments.

With larger lathes you have a wider variability of using complete commercial equipment or worth the money spare parts for your self constructions. If your lathe can handle this head stock you will get a really stiff spindle, and that is always a good approach to this subject. And for milling and drilling jobs the 4000 rpm will be sufficient.

Achim

 

[ShedBoy]

This is on my to do list. I have a some stepper motors from a photocopier which I am planning to use. I was thinking of using tapered bearings to prevent play but have seen several version with just straight bearings. How do you control play with straight bearings without putting too much side load on the bearings?

 

[steamer]

My small lathe is a SB 9"....plenty stiff enough.

The Quickstep is a bit pricey for my blood. The spindle I obtained was $60. The bearings are in great shape, and the housing I'll discard. I'll put another $100 into it I suppose.....but still not $1600 American

It has been designed to drop on my AXA post and put the spindle on center. it consists of a new bearing housing which contains the WW spindle bearings. Drive is from a bed mounted 1/4 HP induction motor.

There will be a through bolt hole in the body so that I can mount it on a vertical slide for wheel cutting.

Dave

 

[shred]

A pro machinist friend has been toying with the idea of getting a Swiss-type machine for his shop. A lot of the value there comes in being able to index and lock the spindle in certain places so the sub-spindle can work. Without the CNC control & drive which you won't have, a good clamp and indexer for the main spindle would be extremely useful.

 

[steamer]

I am either going with a index plate with circles of holes, or a spindle dividing attachment.

Both will mount to the back of the spindle.

I've layed out an idex plate that covers at least the 4 clocks I have plans for. But that is still limiting.

I would like to find a small dividing head that I could set up for this....like a Myford.

Dave

 

[steamer]

This is on my to do list. I have a some stepper motors from a photocopier which I am planning to use. I was thinking of using tapered bearings to prevent play but have seen several version with just straight bearings. How do you control play with straight bearings without putting too much side load on the bearings?

The bearings aren't straight on the drill spindle. They're tapered which takes up the play

The lathe spindle bearing is straight though, and will need to be adjusted properly for this operation.

Dave

 

[steamer]

Here's picture of my "BIG" indexer I use to make small bolts ect. The chuck is a 5C collet chuck.

The indexer is 24 position...Works a treat.

INDEX PIN IN

INDEX PIN OUT

The tall plate position is so that I can use the index pin with my 10.5" faceplate.

Dave

 

[steamer]

Interestingly enough. SB made all these attachement...good luck finding them...at any price!

http://www.lathes.co.uk/southbend/page9.html

http://www.lathes.co.uk/southbend9-inch/page2.html


The former is what I have in mind, though not with gear teeth, but with traditional index holes.

Dave

 

[MachineTom]

If you have a 2hp + aircompressor an extended shaft inline die grinder is very quick. The one I have is 1" shaft, fits in the #4 boring bar holder. thin cutoff wheel make good slitting saws, internal grinding of about 2" deep. But it does suck air, Lots of air.

 

[steamer]

;D

LOL

My air compressor couldn't run a watch :big:


But it's a good thought anyway....Thanks for thinking of me Tom.

Dave

 

[steamer]

Looking at my F1 dividing head, I think an adapter can be made to mount that on the back of the SB.

That should work fine....

Dave

 

[Antman]

Hi guys,
Thanks for all your replies and the discussion. I wish I could have been part of it. What a weekend … I thought we would have a quiet one and I could get some shop time and spend some time on this thread … but … We had a visit by some cuzzies from the Big City which was real fun getting visitors in our neck of the sticks and then today on their way back to Babylon they drove the car into a pothole so the whole of today, Sunday, was spent in mounting a rescue mission.

Ant