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Mini Metal Lathes.

Toke

Toke

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This may sound silly.
Is your parting tool made from the right kind of tool steel.
The kind where the asymmetric profile ensures that the cutting edge is the widest part.
(I have never had the problem with a full size lathe)
 





Mohrenberg

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millirad said:
Just one thing about the HF lathe. Eventually you will be humming along and all of sudden the lathe will stop turning and you will see the bit stuck in the material you were cutting. Don't panic. Quickly shut the power off and retract the bit away from the material it was cutting. Usually copper or stainless steel, when this happens. While the bit is still backed off, turn the speed pot to zero. Turn the power back on, and turn the speed back up. You will find that it wasn't broken after all and you are ready to go back to work. There is an over-current sense that will shut it down if the bit grabs. Unless you're unlucky. Good luck
Click to expand...

Oh yeah, I've done this about 1000 times already.

Last night I cleaned off my table and the lathe....it was freakishly dirty!

I also had to readjust all those little screws that the x axiz slides on as it was becoming wobbly
 
Mohrenberg

Mohrenberg

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Toke said:
This may sound silly.
Is your parting tool made from the right kind of tool steel.
The kind where the asymmetric profile ensures that the cutting edge is the widest part.
(I have never had the problem with a full size lathe)
Click to expand...

heh.....my parting tool was a different carbide bit that i "modified"

Wonder why they don't just make attachments for this mini lathe.
I saw a cool thing where a guy took his HF 7x10 lathe and made a mill attachment. It was pretty awesome.
 
Toke

Toke

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Mohrenberg said:
heh.....my parting tool was a different carbide bit that i "modified"
Click to expand...
Well the important part is to replicate the triangular/trapezoid cross-section to reduce friction.

Wonder why they don't just make attachments for this mini lathe.
I saw a cool thing where a guy took his HF 7x10 lathe and made a mill attachment. It was pretty awesome.
Click to expand...
I have seen something like that, a claw from a drill stand were fixed to the land. It gave debt and sideways movement only, allowing you to e.g. mill groves in a shaft for a fan wing or cogwheel.
 
kiyoukan

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i had a crazy idea i wonder if i can automate my lathe with my stepper motors.
I could turn out heatsink very fast. i would have to do some of it manually but i could do alot of the leg work automated.
I hope i get my lathe soon.
 
Flaminpyro

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Speed pot ? over-current sens ? not on this HF lathe, if you want to change speed you have stop
the lathe and move the belt/belts, and the current sense is my hand hitting the off switch :crackup:


millirad said:
Just one thing about the HF lathe. Eventually you will be humming along and all of sudden the lathe will stop turning and you will see the bit stuck in the material you were cutting. Don't panic. Quickly shut the power off and retract the bit away from the material it was cutting. Usually copper or stainless steel, when this happens. While the bit is still backed off, turn the speed pot to zero. Turn the power back on, and turn the speed back up. You will find that it wasn't broken after all and you are ready to go back to work. There is an over-current sense that will shut it down if the bit grabs. Unless you're unlucky. Good luck
Click to expand...
 
Toke

Toke

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No problem, you just replace the motor contactors with one of these babies.
The forward/reverse switch is already in the switchbox, so all you need is to install a speed setting pot on the front, a braking power resistor, and program the unit. :D
 
millirad

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crackup.gif

crackup.gif

crackup.gif


Speed pot ? over-current sens ? not on this HF lathe, if you want to change speed you have stop
the lathe and move the belt/belts, and the current sense is my hand hitting the off switch
Click to expand...
 
Hemlock_Mike

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I have the 7x10 lathe that Greg is selling. I have, over tine acquired the extra tooling to make stuff.
The "Take-up" refered to above is normal on most lathes I have ever run -- we call it backlash -- the space in the threads.

I don't use a parting cutter either. Slow the rotation down and hold a hacksaw on it. Easy, simple and you can face it to size later.

HMike
 
Mohrenberg

Mohrenberg

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Hemlock_Mike said:
I have the 7x10 lathe that Greg is selling. I have, over tine acquired the extra tooling to make stuff.
The "Take-up" refered to above is normal on most lathes I have ever run -- we call it backlash -- the space in the threads.

I don't use a parting cutter either. Slow the rotation down and hold a hacksaw on it. Easy, simple and you can face it to size later.

HMike
Click to expand...

I was doing this for the first day or two on 1" aluminum, but it just took so damn long to cut through!

Right now i just stick it in the vice and man-handle it. It wears me out and i'm covered in sweat by the time i get through it, but it's a lot quicker.

I've been playing with making hosts...which is starting to look promising other than the time it's taking me.
I don't have the right cutting bit so i'm using the thread tap and dies. I use the 3 jaw chuck, and the tail stock to keep them centered... this is also physically demanding.

my shoulders were hurting for about the first week of playing in the basement but now i think i'm getting use to it.

I've got my lathe, a tv, and a fan in the basement, so i've been spending about 8-10 hours a day down there. The woman isn't happy about it.
 
O

onion

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Slack.

That is your biggest problem with machines with feeds.

If you feed your tool in to your work, touch and make a cut a 1/8 or so of the amount you want to take off.

Stop the lathe then take your mic and measure the amount. If you need say, 15 thousands of a inch more, then move the carriage back from the work.

DO NOT move the tool back from the work. Once the tool has cleared the cut then dial in the .015 you need and start the cut again.

Should you pull the tool away from the work, then you add the slack in the screw and you lose your reference.

Big lathes can have as much as 15 to 20 thousands of slack. If you dont control that, you never know were you are relative to the work.

Hope this helped.

Onion
 
O

onion

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Also, unless you have a REAL GOOD grinder I would recommend carbide bits. They are either sharp or broke.

You dont have to worry about angles of clearance when grinding a tool bit face. Just pop in a new one.

A hint or two.
The softer the material the quicker the tool will 'dig'. Brass is the worst.
Get you some 'soluble cutting oil'. Its a water based cutting lube and will make cleaner and smoother cuts.
Never use air to blow off your lathe. It forces shavings into cracks where they will rust the ways.

Onion
 
villalaser

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Morgan said:
Parting tools are an a**e, IMO! I've tried a few and they simply end up chattering, even after trying to make one myself. I think I'm missing something here because I don't think it should be that hard. I now have one that works well but even with this one it still doesn't beat cutting the piece whilst in the lathe with a hacksaw for speed! (Not turning of course.) It's no where near a neat enough cut but I'm usually facing off the cut end anyway. Parting tool leaves a nice(ish), finish but facing off just makes me happy! I hate being a perfectionist!

Can any of the experienced machinists give a link to tool cutting and tool shape for us? I'm finding my way slowly but any hints and pointers will be much appreciated. I know a steel tool has to have a good positive angle rake; aluminium has less; and brass is surposed to have a negative rake but any elaboration will help. (Particularly on grinding our own parting tool!)

M
:)
Click to expand...

Im not a experienced machinists. But ive ben useing this tool I made from the crap HF bits I had, with decent results.
I still reface the piece I cut off, but it beats numb hand's from a sawzall.
 

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Mohrenberg

Mohrenberg

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heh thats funny.

I got a little mini saw from HF for $25. it said it would cut aluminum, steel, and brass in 1/10th the time of doing it by hand.....and i'm sure it would if the blade didn't stall ever 2 seconds!
so that was a waste of money. It's still a sweet little tool that cuts plastic very nicely.

I've gotten pretty good as chopping with a hack saw...maybe i'm just getting stronger from it :D
 
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