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Cutter selection and set up on lathe

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Creativechipper

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#1
I am getting ready to cut some aluminum as a 1st cut ever.
So I have a few questions:
Why does my compound slide have grooves and a big area that my cross slide and tool rest will never be able to travel, due to a hole and plug on the compound that mates to the cross slide base?
What sort of angles should my QCTP and cross slide be at for a facing cut?
I have a selection of Hss tools and not sure on orientation and choice of tool?
I mounted one up and took a guess at position but not sure?

Let me know what you think.

Thanks for the guidance!!
 

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ttabbal

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#2
I think you're getting terms mixed up, so let's start there.. The part with the QCTP mounted on it is the compound. The part the compound sits on is the cross slide. Your cross slide is like mine, and has T-slots on it. Under the compound you will find 2 bolts. Loosen them a little and you can slide the compound anywhere on the cross slide and rotate it. You can also remove it.

For a facing cut, you want to lock the compound and have the tool pointing at the side you want to face. To lock the compound, look at the Allen screws on the side of it. The one without a nut is the lock. Snug it up, it doesn't need to be super tight.

For normal turning, most of the bits pictured don't look great. Ignore the oddly shaped HSS in the last picture for now. They are special use grinds. The lower HSS looks like it might work, though the top rake is a bit light for aluminum. The top HSS in that picture looks like a threading bit to me.

I have no experience with brazed carbide, so I can't say on those.

Start with light cuts of about 0.010" and see how it goes.

You should consider learning to grind. There's a sticky at the top of the beginner forum where you can ask for models and get all sorts of information about it. There's no way to tell from the pictures how well ground and honed those bits are.

What lathe is it? It looks a lot like my PM1127.
 

Creativechipper

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#3
weiss250f, 10x30
I can rotate my compound but it swivels on a nipple. So I cant slide it up and down the slots that its bolts are in.
I have taken it all the way off, maybe I am missing something here?
 

Cadillac

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#4
Here's acouple tips
Your qctp has two sides to mount the tool holders. One side of the dovetails should face the chuck and the other farthest from the operator or closest to centerline of lathe. Your tool should always be exactly level with center of lathe or a touch lower. I also have a lathe with a similar cross slide. Mine has a pin though with two corresponding holes in the top slide. Those mounting positions should give you the ability to use the capability or size of the machine.
To answer your question put a tool holder in the front dovetail of qctp. Use the tool in your first picture with the cut on the right side. Mount in tool holder with cutter facing towards center of lathe. Your tool will be perpendicular to the chuck. That's the best way to face a part. The tools you picture have a chip breaker ground in them. Should work very well. Although you want to work from the OD to the center with that tool. Watch some YouTube videos some are very resourceful. Good luck
 

Creativechipper

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#5
heres a pic under the compound
 

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Creativechipper

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#6
So for cutter placement and alignment, more like this?
 

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Cadillac

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#7
Yes my top slide is the same so you should be able to put your compound slide mount in either hole and bolt it down. And yes that's how your tool should be oriented for facing. I'd use the tool in your first picture before that one. Just make sure either way that the tip of tool is touching work and the back of tool is a hair away so the back of tool is not dragging on work piece.
 

Creativechipper

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#8
The cutter in which image?
Image #3843 with the left and right cutters?
 

Creativechipper

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#9
Here's another couple angles with a different hss tool

I know there must be an optimal position vs the positions I have?

What is a good position for the cutter?
I have watched a lot of videos but its so hard to see the angle and exact type of tool to cut ratio. Then my cutters don't look quite like the ones I have seen either..hmm
 

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francist

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#10
You should be able to do something with the last cutting tool you've shown, but play with the angles a bit. More like this

image.png


You can also come at it with more of an angle (I tend to this way, myself) like this
image.png
This second method is only good for the facing cut though, you need to reposition for the turning cut otherwise you drag the back corner.

What you should be noticing though, is that it's only the tip of the tool that contacts the work. Not the flat faces of the grind. Even though the angles can be used to advantage, they are not so critical for your purposes right now. The main thing is don't drag on the whole face of the cutting edge.

-frank
 

Creativechipper

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#11
Much appreciate the drawings, I think i understand. Thanks
I am just trying to understand what end is up on some of these tools I have..lol
Luckily I can go slow and will practice with no tool 1st and get used to how the machine moves and operates.
really nice set of videos by MIT, I am on number 3 but will practice doing all the stuff in #1 to start off.
 

mikey

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#12
Can you provide some better pics of your tools? It looks like they lack enough relief to avoid rubbing. I can't see if there is adequate rake, too. As is, those tools probably won't cut well for you.
 

francist

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#13
There's also this guy, ThatLazyMachinist, if you haven't run across him. Hasn't put anything up for a while, but his earlier videos really were catering to the absolute beginner. Good information nonetheless though.

https://m.youtube.com/channel/UCOfQ4Ufy4s7GJB3h9VieY1Q
 

Creativechipper

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#14
Heres a few different angles of the HSS set of accusize tools 8pc set.
I hear good things about hss vs carbide inserts and braised carbide. So I ordered up a set of 1/2" was about 80 bucks so not a cheap set.
I picked up a set of 1/4" indexable cutters but I keep hearing use hss for 1st cuts.
let me know what you think...
Thanks
 

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mikey

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#15
Okay, the tool in image 3853 should be okay. When facing, you want to orient it so that the point of contact is at the forward part of the side edge, up near the tip. You will need to angle the tool like the pic below:

IMG_5647.JPG

For turning, you want to orient the tool so that the shank of the tool is roughly perpendicular to the work piece.

IMG_5649.JPG

I think the side cutting edge angle on your tool will work, although I prefer a different angle myself. Give it a try and see how it works for you.
 

Cadillac

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#16
This tool in your pic. The one On the bottom 5A7F844B-BF2C-4524-BE0E-DEC305CF53A7.png
For normal turning “towards the chuck use the top one”. For facing or turning towards the tailstock use the lower. Should work well.
 

Creativechipper

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#17
Thanks for the input, it helps !!

Will let you know how it goes.
 

bill stupak

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#18
Check this vid
It shows the basics of tool geometry . Stu
 

Creativechipper

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#19
Good video
I will have to get a grinder going soon.
Thanks for the link

Took a few pics after I read all your replies and watched the videos.
This is what my set up looks like so far for my 1st face cut to be made soon.
 

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Creativechipper

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#20
Yes my top slide is the same so you should be able to put your compound slide mount in either hole and bolt it down. And yes that's how your tool should be oriented for facing. I'd use the tool in your first picture before that one. Just make sure either way that the tip of tool is touching work and the back of tool is a hair away so the back of tool is not dragging on work piece.
I tried putting the top slide in the other hole, lol, real funny, that disables the feed wheel for it and the holes are two very different holes.
Really wishing and wondering why they built it like this. Even an oil ball at that end but I cant use it with the nipple in the slide to key it in place, unless I drill a hole.

Any reason not to drill another hole or two? Or am I supposed to rotate the cross slide on the dove tail rails 180 degrees, to move the silly hole to the other side of center?
 

Cadillac

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#21
I’ll take a picture of my top slide when I get home. Looking at yours you only have one position. The Allen screw is holding the leadscrew nut under topslide. I don’t see any reason why you couldn’t bore another hole. I can take some measurements but I think the holes are about a 1” apart.

I do like how they put Oiler ports in the topslide. I had just took my saddle apart to put oilers in it. Were none originally. 0171F69A-874A-4E5B-A6E5-3B2B6D5650FD.jpeg I put two on the v slide and one on the back rail. I am in the process of scraping it along with the cross slide.
 
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