Mills and Lathes

link1896

link1896

Mr Greenfield
Dales, what’s the alignment like? I recently helped a mate setup his old but almost unused lathe, by grinding the chuck jaws (like I did with mine), and using ground iron rod that I couldn’t measure as anything but perfect with the mic, we got his 3 and 4 jaw chucks to within about 0.015mm @ 400mm out from the chuck. With gentle adjustment I got the head to bed alignment in both x and y to less then I could measure with the dial gauge. He’s happy. Feeler gauges under the head for the win.
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
I havent run it yet. I have the factory check sheets but I intend to check it myself. How level is the bed on your lathe? I was surprised this was not mentioned in the destructions.
 
link1896

link1896

Mr Greenfield
Last decade I built a bench for mine using 120x120 hard wood, in an earthquake it’s where I’d hide, but no doubt it is forever moving with humidity changes.

Running the carriage along the bed with a known straight, stationary rod in the chuck, place dial gauges both sides and below the rod. This should show if the bed is twisted on the base.

The rabbit hole goes down a long way.
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
link1896 said:
Last decade I built a bench for mine using 120x120 hard wood, in an earthquake it’s where I’d hide, but no doubt it is forever moving with humidity changes.

Running the carriage along the bed with a known straight, stationary rod in the chuck, place dial gauges both sides and below the rod. This should show if the bed is twisted on the base.

The rabbit hole goes down a long way.
Click to expand...
I have such a rod!

Who is using a QCTP? I will need to make a new toolpost bolt and sleeve... Job #2.
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
The tool post bolt has a male M22x2.0 thread into the cross slide. Not much room to work with and while I was totally shit cutting threads on my old lathe I found that it took about an hour to understand the hieroglyphics to determine which gear set was correct for a 2mm pitch. After sorting this out I had a go at cutting the thread and discovered I am still shit. So I found a die nut and will use that instead.
 
link1896

link1896

Mr Greenfield
Dales Cannon said:
The tool post bolt has a male M22x2.0 thread into the cross slide. Not much room to work with and while I was totally shit cutting threads on my old lathe I found that it took about an hour to understand the hieroglyphics to determine which gear set was correct for a 2mm pitch. After sorting this out I had a go at cutting the thread and discovered I am still shit. So I found a die nut and will use that instead.
Click to expand...
Cutting threads is the hardest thing to master on a lathe I reckon, don’t loose interest.

I mangled that fork brain cartridge foot part I made with the schrader valve 5 times before I had one I was happy with. Super tricky, ~8mm OD at the end, 220mm long, hollow. Took 2-3 hours to make each one. Worst part, NFI where the good one is, after packing up and moving the lathe after my divorce, I can’t find it.

Start with 2012 Aluminium, good carbide insert tools, lube ( I like inox spray), go slow. Give yourself a dead zone after the thread, where you’ve decreased the OD. Never ever disengage the half nut. Experiment with tool height, depth of cut. It’s half back Magic. Different stock behaves differently too. This is why I only work with 2012.

Would be a bunch of good clips on YouTube.
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
Problem is I have a step up after the thread. I cut a recess with the parting tool but cannot afford any bigger gap because there is only 3 threads holding it in. Die nut will do the job. I cut some play threads on a length of scrap mild steel and the first four were ok...
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
The M18x2.0 die nut I bought arrived and it was a different size to my die wrenches and the ones I have access to so as I am an impatient git and couldn't be arsed making the die holder as above I did a bodgy and bored out some pipe and well drilled and tapped some holes in it to stop the die turning inside... ...and then used a tent peg to turn it...



This allowed my to thread the QCTP bolt. Then I machined up a washer for the bottom section of the QRTP rather than waste a heap of material.



Quite a bit of difference between the two bolts. The QCTP bolt is four different diameters and quite a bit longer. I made it so I could use the handle that came with the other tool post for easy spinningness. I have no idea how I managed to do stuff before I bought the mill/drill. I just milled a flat on one side of the bottom shoulder so the bolt can be tightened in place. I guess I would have done that with a grinder previously and maybe cleaned it up with a file. The bolt is a spare 4150 pin off the tractor and it doesn't turn nicely in its hardened state but meh it is good enough and mostly hidden.

Out with the old...



In with the new...





To be totally honest not something I would bother with if I had to pay the retail price for the QCTP however now I that it is fitted it makes changing tools much faster and easier. I have 4 tool holders so I will set up the parting tool, boring bar and one each of the left and right tools. Because the majority are 16mm it is simple to swap them out in any case and I don't need to fluff around with packers.
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
The old tool post needed shims to bring the tools to the correct height. When you change tools it is a pita because you need to make sure the shims stay in place and the swarf doesn't get caught and change the alignment. Not a big deal but still it is something to watch. The quick change idea is to have tool holders with the tools already screwed and locked in. Changing height is as simple as twisting the knurled nut on the holder after you loosen the holder. The large hex on top turns a cam lock which secures the holder in position. Changing a tool is as easy as loosening the cam lock, lift out the old holder, drop in the new and lock the cam. First world problem as I said. Lots of people just load up the old style tool post with various tools they use all the time. Boring bar, parting tool and a couple of other tools but these can get in the way especially if you are turning between centres. I was told by an old old machinist to keep the lathe free of spare tools and just have the one you are using. He got caught up in his apprentice days and the scar from a spare tool on the post was enough to convince me he had a point. Anyway it is something real machinists use so I had to do it. And it came with the lathe from Taiwan so must have been meant to be used.
 
S

SummitFever

Eats Squid
Weird that its only got two quick change sides. Have not seen that before. Are the tool holders readily available or a standard size? If not, stock up on them now while you can. Also, I can't see from the pics but does the bottom of the tool holder where the tool sits have a 45 deg V so you can hold boring bars/rounded tools? If not, get some that have that feature.

Only other thing to watch is that when you're locking the tool holder in place, the height set screw can turn and mess up your height.
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
Small lathes only get two but that is fine. I can get holders for $40 ea so will probably get a couple more assuming they are tge same. This QCTP isnt the one H&F sell but is another brand. Looks similar but is a bit taller though the holders look identical. The lathe doesnt usually come with it but this was in the box... One holder is set for parting tools with a different offset and the others all have vee grooves. Know about the height adjuster. The hard way on a work lathe. A parting tool in many pieces.
 
link1896

link1896

Mr Greenfield
Nice work Dales.

Many 2 sided QCTP on eBay. I’m tempted for a more elegant 3 or 4 sided affair. I currently have feeler gauges to shim tools to right height, cheap eBay feeler gauge packs, the stack stays with the tool when I swap out. Does me but a QCTP would be nice.
 
link1896

link1896

Mr Greenfield
Adjust tool height by looking at the cut pattern. But certain metals at certain surface speeds you don’t want to be at centre anyway.

Lots of black art here
 
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