What lathe?

[Lakeside53]

Carbide Inserts suck on small lathes. Cheap carbide sucks on all lathes. You do get what you pay for.

Look up the SFM and DOC requirements for the insert in question (they all have specific data and it's all over the map). Basically, the tool pressure required to cut exceeds the rigidity of small machines, you get chatter so the user dials back the DOC or feed rate and the surface finish (or the ability to hit a number) goes to hell.

I started with a 9x20, movce quickly though a couple of EMCO V10p's (I love those machines), and now have a heavy 14/40 lathe (built like a 16x60). I use negative rake carbide 90% of the time, but even then when it matters I still reach for HSS for the last thou or 10ths. My minimum DOC with the postive rake finish grade carbide I have is about 3-5 thou. Some times I can sneak it to 2 thou, but...

Carbide in soft'ish steel requires SFM of 300-500. HSS is 40-80. You like machining fast to a shoulder? :msp_mellow:

So... if you really want inserts, you can buy HSS inserts in the standard sizes of carbide. If you really really want carbide, choose the highly positive rake finish grades. I like both the DPxx and WPxx series over CCxx.

A great starter carbide set is the MADE IN USA TT321 sold at Enco. I have a set and use them often. Even TPMM (or whatever) USA carbide won't break the bank. Don't get the "import set"; the hold down screws and holder are made of chewing gum.

 

[blsnelling]

For the piston you would need a right hand turning tool. For the base you will need a left hand turning tool.

What style holder? SCLC? I don't know what that means, but have seen them mentioned a couple places.

 

[Lakeside53]

Madrels question: I make them from steel. I can see aluminum for cylinders, but there are other uses for mandrels other than saws!

For easy to make accurate mandrels use free machining steels - like 12L14. You can get a mirror finish with no sweat and cut 10th's with HSS. Keep 1018 and A36 for welding projects. Alternatively, use 1144 stressproof.

If you use aluminum, use 6061T6 - machines decently with good surface finish. On your lathe you might find 2xxx a bit gummy and 7075 a difficult. If you get it hot while turing, let it cool before final cuts or you'll be way out on your target measurements.

 

[FATGUY]

For the piston you would need a right hand turning tool. For the base you will need a left hand turning tool. For inserts to be worth it and effective you need to use much higher surface speed, which means higher spindle speed. Throwing a cylinder on a mandrel out of the machine at 600 rpm can send you to the ER or severely damage the lathe. It is best to get your feet on the ground with HSS, then move to indexable carbide when you get a handle on things.

Listen to this Brad.

 

[FATGUY]

Carbide Inserts suck on small lathes. Cheap carbide sucks on all lathes. You do get what you pay for.

Look up the SFM and DOC requirements for the insert in question (they all have specific data and it's all over the map). Basically, the tool pressure required to cut exceeds the rigidity of small machines, you get chatter so the user dials back the DOC or feed rate and the surface finish (or the ability to hit a number) goes to hell.

I have a heavy 14/40 lathe and use negative rake carbide 90% of the time, but even then I still reach for HSS for the last thou or 10ths. My minimum DOC with the postive rake finish grade carbide I have is about 3-5 thou. Some times I can sneak it to 2 thou, but...

Carbide in soft'ish steel requires SFM of 300-500. HSS is 40-80. You like machining fast to a shoulder? :msp_mellow:

So... if you really want inserts, you can buy HSS inserts in the standard sizes of carbide. If you really really want carbide, choose the highly positive rake finish grades. I like both the DPxx and WPxx series over CCxx.

A great starter carbide set is the MADE IN USA TT321 sold at Enco. I have a set and use them often. Even TPMM (or whatever) USA carbide won't break the bank. Don't get the "import set"; the hold down screws and holder are made of chewing gum.

you have a link for that Andy? I'd love to see an HSS version of a VNMG331.

 

[Stihl 041S]

Madrells question: make them from steel. For easy to make accurate mandrels use free machining steels - like 12L14. You can get a mirror finish with no sweat and cut 10th's with HSS. Keep 1018 and A36 for welding projects. Alternatively, use 1144 stressproof.

416 cuts like butter. Maybe? ;-))

 

[Stihl 041S]

Wear boots and cuffless pants. NEVER wear those boots in the house. You WILL screw up the floor covering. Sumo the chips out of your pockets. Wear short sleeve shirts. Wear short sleeve shirts. Wear short sleeve shirts.

 

[Lakeside53]

416 cuts like butter. Maybe? ;-))

Yep, love that stuff. But let's not get Brad into Stainless just yet:hmm3grin2orange:

Hey Brad, ignore all of this and buy some 316 and inconal. I have some Superinvar 36 if you like. So easy to work with on a small lathe.

 

[Lakeside53]

you have a link for that Andy? I'd love to see an HSS version of a VNMG331.

Me too, but that one they don't have. Maybe you can stretch a DPxxx insert

Arthur R. Warner Co. | Specialists in High Speed Steel - Standard and Specialty Inserts

 

[blsnelling]

It's not the carbide I'm after, it's the inserts. At this stage, I want to keep it as simple as possible, and not having to grind my own cutters sounds good. I'll definitely be checking into these.

 

[blsnelling]

I see that inserts not only come in different shapes, but also different sizes. What size/s should I be looking at?

2152

3255

3251

Looks like the 2152 has the largest radius. Would that equal a smoother finish at a slower spindle speed?

 

[blsnelling]

I like both the DPxx and WPxx series over CCxx.

Do you like these better than the CCMWs linked above? LINK

 

[Jim Timber]

Wear boots and cuffless pants. NEVER wear those boots in the house. You WILL screw up the floor covering. Sumo the chips out of your pockets. Wear short sleeve shirts. Wear short sleeve shirts. Wear short sleeve shirts.

Shoes come off at the door - no exceptions!


My last employer offered long sleeve work shirts. I should've gotten the hint about their lack of concern for our safety right there.

One guy in tech school lost a hoodie to a 5hp lathe - fortunately, it came off instead of sucking him in.

Lathes have an insatiable appetite for idiots - don't give them a chance to bite.

 

[Metals406]

Wear boots and cuffless pants. NEVER wear those boots in the house. You WILL screw up the floor covering. Sumo the chips out of your pockets. Wear short sleeve shirts. Wear short sleeve shirts. Wear short sleeve shirts.

Yeah, but should he wear short sleeved shirts?

 

[Stihl 041S]

Yeah, but should he wear short sleeved shirts?

Brad often skims..... ;-))

 

[dozerdan]

Listen to this Brad.

Brad
Don't worry about cutters. I will send you a HSS ground for the pistons and another one for the cylinder base. Once you see them you will be able to sharpen and duplicate them.

Practice with HSS BEFORE you play with carbide.

Later
Dan

 

[Tzed250]

Seems to be a theme here. I DO NOT run a lathe wearing long sleeves. For real Brad, you will enjoy running the machine more using HSS. The chips aren't nearly as hot, and you can watch the work progress at a much slower pace. Grinding tools is not that hard. Cast aluminum is easy to machine. In school you must be able to grind a correct OD tool before you are ever allowed to turn a lathe on. It teaches you principles of metal removal like relief, tool nose radius, rake, etc.

 

[H 2 H]

Seems to be a theme here. I DO NOT run a lathe wearing long sleeves. For real Brad, you will enjoy running the machine more using HSS. The chips aren't nearly as hot, and you can watch the work progress at a much slower pace. Grinding tools is not that hard. Cast aluminum is easy to machine. In school you must be able to grind a correct OD tool before you are ever allowed to turn a lathe on. It teaches you principles of metal removal like relief, tool nose radius, rake, etc.

In the 30 plus years I've used mills and lathe seen some pretty nasty thing happen to new operators wearing long sleeves; long hair etc

Hot chips only sting for a while :msp_biggrin:

 

[parrisw]

For the piston you would need a right hand turning tool. For the base you will need a left hand turning tool. For inserts to be worth it and effective you need to use much higher surface speed, which means higher spindle speed. Throwing a cylinder on a mandrel out of the machine at 600 rpm can send you to the ER or severely damage the lathe. It is best to get your feet on the ground with HSS, then move to indexable carbide when you get a handle on things.

Carbide Inserts suck on small lathes. Cheap carbide sucks on all lathes. You do get what you pay for.

Look up the SFM and DOC requirements for the insert in question (they all have specific data and it's all over the map). Basically, the tool pressure required to cut exceeds the rigidity of small machines, you get chatter so the user dials back the DOC or feed rate and the surface finish (or the ability to hit a number) goes to hell.

I started with a 9x20, movce quickly though a couple of EMCO V10p's (I love those machines), and now have a heavy 14/40 lathe (built like a 16x60). I use negative rake carbide 90% of the time, but even then when it matters I still reach for HSS for the last thou or 10ths. My minimum DOC with the postive rake finish grade carbide I have is about 3-5 thou. Some times I can sneak it to 2 thou, but...

Carbide in soft'ish steel requires SFM of 300-500. HSS is 40-80. You like machining fast to a shoulder? :msp_mellow:

So... if you really want inserts, you can buy HSS inserts in the standard sizes of carbide. If you really really want carbide, choose the highly positive rake finish grades. I like both the DPxx and WPxx series over CCxx.

A great starter carbide set is the MADE IN USA TT321 sold at Enco. I have a set and use them often. Even TPMM (or whatever) USA carbide won't break the bank. Don't get the "import set"; the hold down screws and holder are made of chewing gum.

Listen to this Brad.

Ya! LOL, its what I kept trying to say without going into great detail! Thanks Andy. I did say much earlier that you wont have the HP to take advantage of Carbide. I went through all of this when I got mine, Andy was a great help to me told me more then I could ask for about tooling, now the carbide stuff I have sits on the shelf, and all I use is HSS, YOU WILL GET A MUCH BETTER FINISH WITH HSS ON YOUR LATHE!!!!! Its not hard to learn to grind HSS, you need to learn, so just go ahead and learn NOW. As long as you have enough relief on the cutter, you'll be good, you'll learn how to fine tune as you go along, you can even hone the tip if you wish, you don't want the cutting tip at a sharp point. Lots of vids on youtube about grinding tooling. And like I said before, you'll need the proper white wheel for grinding HSS, and a little bucket of water to keep it cool.

If your just going to use HSS inserts, I can't see the point in that. Just get a blank, you have much more to play with.

 

[Bob Wright]

Download one of these links for HTRAL How To Run A Lathe by the South Bend Lathe Co. You can get newer ones on ebay but most of them are pretty good info wise...Bob
http://www.wswells.com/data/htral/htral_index.html