Vevor 7x14 Lathe 550W with HSS Cutting Tools

[paul_hobby_machinist]

Hello,

New to the forum here and bought a Vevor (though I've seen sold under many brand names). This is my first lathe, but have some basic machining knowledge and how to work with metals. Lathe was delivered, had a big dent in control panel so got a small refund but everything seems operational. Came with some HSS tools too. I've been playing with trying to face and turn brass and plain steel. Both had similar results which were not great. I've added some pictures below. Some things that I think may be creating the awful taper, chattering and poor finish.

• The tool is just slightly above center (vertically) as can be seen from first image. I don't suspect this is a huge issue, but when facing it does leave that characteristic nub confirming that it's off-center. I think this could impact cutting performance? Especially with a bad tool.
• The tools are cheap HSS and I haven't sharpened or ground them in any way (don't have a bench grinder or know best way to do this).
• My lathe isn't bolted down, so it's on a roller on the floor. I couldn't lift it on my workbench. I know this is not ideal, but I don't think it's the main cause of the issues? It may explain the chatter, but it doesn't explain why the tool just doesn't seem to cut at all and produce an awful taper.
• The chips are awful (more of a fine dust, especially with steel), and tons of heat is produced. So it's more rubbing than cutting.
• For the speeds I set them at 2,000 RPM for the steel based on a chart I saw for plain steel at this diameter. Changing the feeds and speeds for both materials seemed to make no difference and both resulted in an awful taper.
• For both I did keep things "close and tight" to reduce flex on the material and tool since I'm not using a tailstock.
• The tool holder has no flex, I tightened up the 3 hex screws to reducer the jitter so I don't think that's a problem either.

I'm tempted to buy smaller carbide tools, so then I can shim them (maybe with a quick change post), but if there's something obvious I should try first, or other improvements I can make to my setup, I'd love to hear! Thanks in advance for the help.

Paul

 

[markba633csi]

That's not looking like a HSS tool. It looks like a brazed carbide tool and is probably dull
The majority of your difficulties are probably there. Often these machines come bundled with cutting tools that are completely unsuitable.
Did you get another set of jaws with your chuck? The set pictured is really for grabbing cylindrical objects and tubing
It's very easy to forget where those jaws are when the chuck is in motion and have a crash into the compound or toolpost

 

[paul_hobby_machinist]

You're right! I'll follow this video and see if I can sharpen them up.

Thanks for the tip ... I now see how they're clearly not HSS.

 

[WobblyHand]

That's not looking like a HSS tool. It looks like a brazed carbide tool and is probably dull
The majority of your difficulties are probably there

That plus being above center isn't helping at all. Just rubbing a dull edge.

The smaller the diameter the work piece (the rod) the more critical it is to be on center.

It also appears that the wrong set of chuck jaws are installed. For most rod like pieces you want the the jaws with the long ends meeting in the center. Like this:

See the jaws that are not installed? Those are for supporting discs and large diameter stuff. For rods, one usually use the one's that are installed in this picture. You will get more support for your work piece if you use the installed jaws in the picture.

 

[paul_hobby_machinist]

Ah right, I was switching the jaws in and out and forgot that the other ones are much better for rods. You're right, that will help much more with supporting the work piece. Thanks very much. So if I can 1) sharpen the brazed carbide 2) use proper jaws 3) center the tool - I suppose by grinding the down the steel "handle" part of the tool? Otherwise I can't think of a way to make the tool lower? Usually the problem is it's too low, and I could shim it up.

 

[markba633csi]

You'll find it difficult to sharpen carbide with a conventional wheel. You can try, but it's tough going.
Ask Santa for a small bench grinder and some 1/4" HSS
I see a market for pre-ground bits
BTW use slow speeds to start with- the charts are often biased toward production shops where time is money and they have to go fast as possible

6 in. Bench Grinder with LED Lights

Amazing deals on this 6In Bench Grinder W/ Led Lights at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

This HF grinder is only 55 bucks and would work fine for HSS

 

[WobblyHand]

Ah right, I was switching the jaws in and out and forgot that the other ones are much better for rods. You're right, that will help much more with supporting the work piece. Thanks very much. So if I can 1) sharpen the brazed carbide 2) use proper jaws 3) center the tool - I suppose by grinding the down the steel "handle" part of the tool? Otherwise I can't think of a way to make the tool lower? Usually the problem is it's too low, and I could shim it up.

Did the tools come with the lathe? Just wondering.

Do you have a steel rule or even a razor blade? Try sandwiching the blade between the workpiece and the tool cutting edge. You need just enough pressure to hold the blade captive. Does the top of the blade come toward you or away from you? Towards you means the cutter edge is too low. Away from you means the cutter is too high. Straight vertical means it's pretty close to being just right.

Assuming the cutter is too high, you need to reduce the tool height. One way (harder way) is to grind the bottom of the tool shank, so the cutting edge is lowered. Another way is to buy the same tools but with a small shank. You may need to install shims to get the edge to the right place.

But I recommend not buying more of these brazed carbide tools for this kind of lathe. I'd get HSS. The carbide needs a silicon carbide grinding wheel or diamond to sharpen it. Not so easy to grind and the carbide dust is not good to breathe. HSS can be sharpened on an ordinary grinding wheel. In any case, make sure the tool shank or the HSS blank is not too tall. Smaller HSS blanks take less time to grind and are less expensive. How tall is the shank on the tooling that you have? 5/16" or 3/8"?

 

[paul_hobby_machinist]

Did the tools come with the lathe? Just wondering.

Do you have a steel rule or even a razor blade? Try sandwiching the blade between the workpiece and the tool cutting edge. You need just enough pressure to hold the blade captive. Does the top of the blade come toward you or away from you? Towards you means the cutter edge is too low. Away from you means the cutter is too high. Straight vertical means it's pretty close to being just right.

Assuming the cutter is too high, you need to reduce the tool height. One way (harder way) is to grind the bottom of the tool shank, so the cutting edge is lowered. Another way is to buy the same tools but with a small shank. You may need to install shims to get the edge to the right place.

But I recommend not buying more of these brazed carbide tools for this kind of lathe. I'd get HSS. The carbide needs a silicon carbide grinding wheel or diamond to sharpen it. Not so easy to grind and the carbide dust is not good to breathe. HSS can be sharpened on an ordinary grinding wheel. In any case, make sure the tool shank or the HSS blank is not too tall. Smaller HSS blanks take less time to grind and are less expensive. How tall is the shank on the tooling that you have? 5/16" or 3/8"?

Yes, tools came with the lathe. From what I've seen it's a common, cheap set nearly exactly like this one:

12mm 11 Pcs Metal Lathe Tools Carbide Bits for Mini Lathe Cutting Tool Turning | eBay

Usage: External Turning Tool. 1 x Set of External Turning Tools(11pcs). Material: Carbon Steel. It is made of high speed steel material, have very good toughness and high hardness. Square Size: 12x12mm.

www.ebay.com

That's a great trick for determining center. I did use my centering piece to determine that the tool is already a bit too high. So yes, unfortunately I'll either have to grind the shank, or buy tools with a smaller shank. Or the more expensive route go with a quick change holder I suppose, but may wait on that.

The current shanks are 12x12mm, pretty big. It's funny they would come with the lathe, and by default be too high. Unless there's that much variance in the parts that for some they're perfectly center or low and can be shimmed. But, I bought the lathe cheap so I wasn't expecting it all to work out of the box.

 

[WobblyHand]

Yes, tools came with the lathe. From what I've seen it's a common, cheap set nearly exactly like this one:

12mm 11 Pcs Metal Lathe Tools Carbide Bits for Mini Lathe Cutting Tool Turning | eBay

Usage: External Turning Tool. 1 x Set of External Turning Tools(11pcs). Material: Carbon Steel. It is made of high speed steel material, have very good toughness and high hardness. Square Size: 12x12mm.

www.ebay.com

That's a great trick for determining center. I did use my centering piece to determine that the tool is already a bit too high. So yes, unfortunately I'll either have to grind the shank, or buy tools with a smaller shank. Or the more expensive route go with a quick change holder I suppose, but may wait on that.

The current shanks are 12x12mm, pretty big. It's funny they would come with the lathe, and by default be too high. Unless there's that much variance in the parts that for some they're perfectly center or low and can be shimmed. But, I bought the lathe cheap so I wasn't expecting it all to work out of the box.

12x12 is too large for your lathe. 10x10 would be the maximum. I have a 7 x 16 mini-lathe. I use 3/8" tooling (9.5mm), but I have a QCTP. You could get some 3/8" HSS and grind some tools. 5/16" would be ok too and quicker to try out. You can get some blanks pretty inexpensively. There's a huge thread on grinding HSS on HM. Highly recommended read. I learned a lot from the thread. Can't say I'm great at grinding tooling, but have made a few special tools out of HSS.

 

[RJSakowski]

I use HSS, brazed carbide, and carbide insert tooling on my lathes. My preference is towards brazed carbide because 1. I am a cheap S.O.B. and 2. carbide offers a greater range of materials that it will work with. and 3. I can grind to suit my particular needs. If I chip a carbide insert, it's toast. change it to a new edge. High speed steel struggles with some of the harder materials. But brazed carbide can be reground many times before it is no longer serviceable. I have some brazed carbide bits that have mere nubs remaining.

A have a 4" diamond disk from HF that I use for roughing the tool shape and I touch up the cutting edge with a diamond hone. I will almost always never use a brazed carbide bit as received. I usually grind an included angle of around 75º and increase the front and side relief. This allows me to use the same setup for both facing and turning.

For special profiles, small features, and form tools, HSS works well. I can also put a keener edge on HSS which produces better finishes. I use bits as small as 1/8" on my 10 x 22 lathe. Smaller bits are easier to grind to a desired shape and can get into tighter spaces. I also have 3/16", 1/4", 3/8" and 1/2" tooling with 3/8" FSS and brazed and 12mm insert being the most often used.