Drilling and Milling on the Lathe

[Anorak Bob]

I bought an incomplete Durden toolrest base from F W Hercus for my Tough wood turning lathe. I was supplied with a sketch of the missing parts. The base is cam operated, a 1" bar is supported on a pair of eccentric bushes and the bar, when rotated, raises and lowers a large boss holding the bed clamp plate. Just like a tailstock clamp mechanism but far more robust. The bar slides through the boss providing considerable adjustability.

I had to bore a 1.004" diameter hole at right angles through the boss exactly on the centreline. I centred the boss in a 4 jaw chuck and then fixed the boss to an angle plate. The photos tell the story. I thought the final cut would be with a 1" slot drill but it cut undersize. I was counting on a bit of runout to cut the hole to size. Wasn't any. The intermediate Autolock chuck and the Clarkson slot drill worked flawlessly. I ended up using a 3C collet to hold a 1'' Sutton drill. That bored oversize.

The parts are 1214. I had forgotten how easy the stuff is to machine.

Using the lathe worked perfectly. I used powerfeed during the final milling and drilling. I had considered using one of my mills but what I ended up doing could not have been more simple. Having a tee slot cross slide certainly helps.

BT

[welder]

Nice work as usual :2tsup::2tsup:

[BobL]

I always look with envy at the accuracy and finish you get on your work. Makes my stuff look really clunky. Keep posting though - I'm on a big metal work learning curve at the moment and seeing your stuff makes me want to keep at it.

[Anorak Bob]

Andre, Bob. It's all trick photography. I don't show you the #### ups! Yesterday I was turning the boss down from 50 to 12.7mm. Being lazy, I came unstuck when I tried to peel 10mm off the diameter in one pass with powerfeed. It would have worked if I had engaged the live centre. With no support the cutter jammed and twisted the boss in the chuck, stalled the 1 horse motor but because I was lucky :roll: I didn't destroy my carbide insert. Lucky because 1214 is as tough as chewing gum.

I also had a hell of a time trying to set up the inch bar in the 4 jaw chuck and adjust it so that the bar was running true at the outboard end 300 mm away. I had to reduce the ends to 16mm. If I wasn't lazy the lathe would be level and wouldn't turn a taper. The bar I used was 1 inch 1214. I reckon it was oval not round. I tried my hand at turning between centres yesterday for the first time. I need more dogs. I also need to know how you are meant to centre drill the ends of a long bar larger than the lathe spindle bore.

I've got a long way to go.

BT

[Steamwhisperer]

I tried my hand at turning between centres yesterday for the first time. I need more dogs. I also need to know how you are meant to centre drill the ends of a long bar larger than the lathe spindle bore.

I've got a long way to go.

BT

Easy done Bob. Use your fixed steady for support.

Phil

[Ueee]

Hi Bob,
I don't care what you say, that looks pretty good. :2tsup:

One thing that is mentioned in Harold Halls book is working on the end of a bar too big for the lathes bore. He suggests zeroing the piece in the chuck, setting the fixed steady at the chuck and then moving the steady to the end of the job. I can't try this as my steady won't get close enough to the chuck, due to the gap bed in my lathe, and of course the job would have to be parallel already. You can also set the bar in a cup center to set the steady.

Ewan

Edit: i see Phil beat me to it, i'm a bit slow tonight after a big few days.....bed time i think

[Steamwhisperer]

Not slow Ewan just very thorough.

Phil

[welder]

I hate centering long stuff in the 4 jaw I had to center a piece of 120 mm bar 500 mm long at work the other day pain in the backside :((

[azzrock]

looks great bob. is that a hercus 9" your using? i haven't tried a 5mm doc on my 9" maybe on aluminum Ive done it but not steel.
as for a center drilling long bar if i had to do it id mark out the bar. ie find center of the bar. center pop it and use a fixed steady on the lathe to support the shaft while center drilling or a drill press .
how come u couldn't just set you work up in a four jaw to bore the hole.
makes me feel like some shed work.
aaron

[jhovel]

I also need to know how you are meant to centre drill the ends of a long bar larger than the lathe spindle bore.


Bob, in principle you use a fixed steady to hold the far end still and concentric - then centre drill.

If the part is too long, you may be able to mark the centre with a centre finder and then centre drill it off the lathe - e.g. on a pedestal drill, then mount it on the lathe for turning operations.

Joe

[Anorak Bob]

Hey Boys,

I might take risks but I ain't completely crazy! I was using my fixed steady.:D

[Anorak Bob]

Bob, in principle you use a fixed steady to hold the far end still and concentric - then centre drill.


Joe

Exactly what I did yesterday Joe. Because the bar was out of whack, the chuck end was wobbling about while the outboard end ran true.

Bob.

[Steamwhisperer]

Apologies Bob. I thought you were asking about centre drilling. I'll crawl back into my hole now.

Phil

[Anorak Bob]

looks great bob. is that a hercus 9" your using? i haven't tried a 5mm doc on my 9" maybe on aluminum Ive done it but not steel.
as for a center drilling long bar if i had to do it id mark out the bar. ie find center of the bar. center pop it and use a fixed steady on the lathe to support the shaft while center drilling or a drill press .
how come u couldn't just set you work up in a four jaw to bore the hole.
makes me feel like some shed work.
aaron

Yes Aaron, my '69 ARL. I like it.

[Anorak Bob]

Apologies Bob. I thought you were asking about centre drilling. I'll crawl back into my hole now.

Phil

Come back out Phil. Please. I was asking that question. Lets say you've got a length of unpeeled black scaly nasty 4140. I guess that's where the centre finder comes into play along with the centre punch. You couldn't use a steady because of the ragged nature of the bar. Between centres would be the way to go. Having a level machine is a prerequisite.

BT

[Ueee]

Come back out Phil. Please. I was asking that question. Lets say you've got a length of unpeeled black scaly nasty 4140. I guess that's where the centre finder comes into play along with the centre punch. You couldn't use a steady because of the ragged nature of the bar. Between centres would be the way to go. Having a level machine is a prerequisite.

BT

Bob, In that situation (and only if you didn't have enough meat to cover the inaccuracies of punching and hand drilling centers) i would go: Chuck as true as you can, then use a cup center in the tailstock. You can then true a section of bar at each end to run the steady on, again use the cup center to center the job and set the steady. Now you can center drill each end in turn and you are set to go.

A thought that did just cross my mind, was could you make a bush to fit in the lathes bore, with a spindle up the middle that could hold a center drill at one end and be powered by a hand drill at the other. This way the job could be zeroed in the 4 jaw and drilled very accurately. Just a wild thought.

Ewan

[Anorak Bob]

Bob, In that situation (and only if you didn't have enough meat to cover the inaccuracies of punching and hand drilling centers) i would go: Chuck as true as you can, then use a cup center in the tailstock. You can then true a section of bar at each end to run the steady on, again use the cup center to center the job and set the steady. Now you can center drill each end in turn and you are set to go.

A thought that did just cross my mind, was could you make a bush to fit in the lathes bore, with a spindle up the middle that could hold a center drill at one end and be powered by a hand drill at the other. This way the job could be zeroed in the 4 jaw and drilled very accurately. Just a wild thought.

Ewan

In Bryan's words, that would be a cunning stunt! :U Nice idea Ewan and one that bears further thought. Sort of suggests hardening and grinding. Maybe I need to have a word with my mate Bruce.

Bob.

[Ueee]

In Bryan's words, that would be a cunning stunt! :U Nice idea Ewan and one that bears further thought. Sort of suggests hardening and grinding. Maybe I need to have a word with my mate Bruce.

Bob.

I was thinking about a long bronze bush (or 2 smaller ones for each end) bored to fit a silver steel shaft with a sidelock style holder for the drill bit. The bush could be as simple at a slip fit 90% of the way with a small taper (getting larger) at the outboard end to hold it in place. You could go to the trouble of making it to fit the morse taper and have a nut at the outboard end, but it may mean removing your chuck to put it in and out depending on the chucks bore.

I have not heard the stunning c.....i mean cunning stunts saying in some time....since i worked with other tradies probably....hehehe the things you forget.

[azzrock]

Apologies Bob. I thought you were asking about centre drilling. I'll crawl back into my hole now.

Phil

any thing good in there

[Anorak Bob]

I was thinking about a long bronze bush (or 2 smaller ones for each end) bored to fit a silver steel shaft with a sidelock style holder for the drill bit. The bush could be as simple at a slip fit 90% of the way with a small taper (getting larger) at the outboard end to hold it in place. You could go to the trouble of making it to fit the morse taper and have a nut at the outboard end, but it may mean removing your chuck to put it in and out depending on the chucks bore.

I have not heard the stunning c.....i mean cunning stunts saying in some time....since i worked with other tradies probably....hehehe the things you forget.

How could you forget about cunning stunts, you're half my age! :no:
I have half of the stunt already made in the form of a spindle back stop that I never really finished. Sadly it's made of 1214 which wouldn't be much chop for your suggestion. Still it's got me thinking.

BT

[Ueee]

How could you forget about cunning stunts, you're half my age! :no:

BT

And i have 2 young children.......

[Steamwhisperer]

Come back out Phil. Please. I was asking that question. Lets say you've got a length of unpeeled black scaly nasty 4140. I guess that's where the centre finder comes into play along with the centre punch. You couldn't use a steady because of the ragged nature of the bar. Between centres would be the way to go. Having a level machine is a prerequisite.

BT

Boy it's dark in there.
Still no problem Bob. Clean a section up near the chuck and turn it around to sit in the steady then centre drill. Repeat for other end if turning between centers.

Phil

[jhovel]

... and then there is the option of a cat's head of course..... must make one one day for just this purpose....

crawling back into my hole now....

[Anorak Bob]

... and then there is the option of a cat's head of course..... must make one one day for just this purpose....

crawling back into my hole now....

I'm missing something here Joe. What's a cat's head?

[Steamwhisperer]

You type too quick joe. You beat me by 7 hours. I had plum forgot about a cat head and that's exactly what they are used for, and square and hex and...

Phil

[Anorak Bob]

A search for cathead revealed all. A cylindrical sleeve with radial positioning screws .
Simple. Neat.

Cathead (http://www.angelfire.com/d20/lathework/page12.htm)

[azzrock]

i described one last night but the post is missing.

208322

[azzrock]

a tip on set up
Pass Along MW (http://www.homeshopmachinist.net/passblast/mw/mwapril08.html)

[Anorak Bob]

i described one last night but the post is missing.

208322

And so is the bottle of Carlton Draught. Obviously not your lathe Aaron.:U

[Anorak Bob]

a tip on set up
Pass Along MW (http://www.homeshopmachinist.net/passblast/mw/mwapril08.html)

I don't get it. How are the chuck jaws deflecting the work if the work has been set up in the chuck to run true? And what's the wire doing? Maybe I'm still half asleep.

[Steamwhisperer]

I don't get it. How are the chuck jaws deflecting the work if the work has been set up in the chuck to run true? And what's the wire doing? Maybe I'm still half asleep.

Hi Bob,
I think the wire is wrapped around the bar and the chuck jaws clamp the wire creating a pivot point rather than trying to deflect the bar.

Phil

[azzrock]

no that's not mine. mine is out of action.
the hercus is still going strong.
the cats head i have has only 3 bolts for positioning the work.
i just got that photo from the web for your benefit.
Im still thinking about your 10 mm cut on the hercus.
does yours spine faster than mine? what sort of cutting
tool was this?

:2tsup:

[Anorak Bob]

Ah Ha! Exactly what was happening on Saturday. Thank you Phil.

[Steamwhisperer]

Ah Ha! Exactly what was happening on Saturday. Thank you Phil.
No worries Bob. I had to giggle though as I thought I was bad at explaining things but that article made me look like the Zen Master of explanations.:D

Phil

[azzrock]

does this mean ive posted some thing useful?

[Steamwhisperer]

does this mean ive posted some thing useful?

Very useful Aaron. Tips and tricks are always handy.:2tsup:

Phil

[Anorak Bob]

no that's not mine. mine is out of action.
the hercus is still going strong.
the cats head i have has only 3 bolts for positioning the work.
i just got that photo from the web for your benefit.
Im still thinking about your 10 mm cut on the hercus.
does yours spine faster than mine? what sort of cutting
tool was this?

:2tsup:

The standard 9" lathe has a top speed of 700 rpm with the single drive vee belt pulley setup. I have high speed pulleys on my lathe. I was running the machine at 1200 rpm. The highest speed it will run at is 2650 rpm. I used a Kennametal CCGT 09 T3 04 KC5025 grade insert in a Kennametal SCGCR 1212 tool holder.

More here - http://www.woodworkforums.com/f65/need-speed-130451/

[azzrock]

roller bearings headstock. i didnt notice that in the photos. i still don't understand why you didn't
bore out the hole in a 4 jaw chuck?

[Anorak Bob]

roller bearings headstock. i didnt notice that in the photos. i still don't understand why you didn't
bore out the hole in a 4 jaw chuck?

Here is why. Be like hanging from a rock face by a fingernail. I had thought of using an angle on a faceplate but what I ended up doing worked O.K. Even if I could have held it in a 4 jaw, centreing the work would have been hellish.

[Abratool]

Hi Bob,
I think the wire is wrapped around the bar and the chuck jaws clamp the wire creating a pivot point rather than trying to deflect the bar.

Phil
I think finally understand.
Thanks for the explanation Phil.
regards
Bruce

[azzrock]

its a bit like why the suspension on a solid single axle caravan is no good.