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HVL-H Feed Speeds / Problems Turning 416 Stainless

majohnson

Cast Iron
Joined
Jan 3, 2013
Location
Erie, CO
My HLV-H has the larger case for the variable feed speed control. I know roughly where the percentage markers should be, the screen printing is gone I guess from previous owners cleaning the machine. I was wondering if anyone has a plate with the actual feed rate or is there just the percentage platesthat are available. Only running my lathe for a few months, I am still not sure on the feed rates.

I am reasonably sure the problem above is part of my problem with trying to cut 416CD. When I try turning 416 the surface finish is terrible. I pulled my carriage apart and readjust everything with no change. I can turn 304 with pretty fair results, aluminum turns with a mirror finish.
 
Is this 416 annealed? If it's anything like 420, annealed is a gummy, smeary mess that takes high sfm and a deep cut to get anything approaching decent out of.
 
My first guess is tooling and the annealed condition of the 416. 416 machines very easily and with a good finish in the 26 to 32 RC range. It finishes even better in the 32 to 36 range but tool pressure is a little higher and technically it should be run a little slower. I have some annealed bars but have never tried to run them on the HLV-H as I like the heat treated better. The only use for those annealed bars lately has been cut into 8 to 10 inch lengths then heatreat and anneal at 300F. Pretty hard then but do they ever finish pretty. We use inserts that would be better suited for softer metals (High positive rake, never any negative rake inserts) and have no issues.
The speeds we use are between 1100 and 1400 RPMs because that is where we run everything not just 416. Feed with no numbers 9 to 10 o'clock, no special reason there either. Finish cut .003 per side or .005 or .006 inches because that is what I always do nothing special about 416 when heat treated.
 
The 416 is cold drawn, I ordered it from Online Metals. I thought it might of been a material issue and they sent me another piece to try. I am not sure of the hardness, I will research and post a follow up.

Ron,
High/Low feed switch? The only High/Low I am aware of is spindle speed. Could you explain please.

Thanks,
Mark
 
An interesting question would be.......what tool(s) are you using to "achieve" this crappy finish?
:D

If you want to at least get an idea of FPM, and compare that to milling suggestions for your material, a long reach (1" or 2") indicator and a stop watch (app on yer phone now dayz) will give you that for ballpark .......pitching.......turning.
 
An interesting question would be.......what tool(s) are you using to "achieve" this crappy finish?
:D

If you want to at least get an idea of FPM, and compare that to milling suggestions for your material, a long reach (1" or 2") indicator and a stop watch (app on yer phone now dayz) will give you that for ballpark .......pitching.......turning.

It's actually rather cheap to add a permanent tacho to the spindle.

That will not only give you the "real" RPM, but show if the variable drive is slipping under load while in the cut.

Stainless "300 series" - no more specific than that - I got from a Speedy "fire sale" a while back was a tad gummy, too. Online's drops may be much the same. BFD - it's just for some knobs.

Need better, yah buy better, and if you DID "buy better", it should respond to the advice showing up arredy.
 
Um..........WELL, we'll need one of those as well wont we Beel ?


It's actually rather cheap to add a permanent tacho to the spindle.

That will not only give you the "real" RPM, but show if the variable drive is slipping under load while in the cut.

Stainless "300 series" - no more specific than that - I got from a Speedy "fire sale" a while back was a tad gummy, too. Online's drops may be much the same. BFD - it's just for some knobs.

Need better, yah buy better, and if you DID "buy better", it should respond to the advice showing up arredy.
 
Um..........WELL, we'll need one of those as well wont we Beel ?

10EE's come with one.

More useful than a faded "percentage" plate was even when new, I'd guess.

Some digital readouts are under ten bucks. Yah need an optical or mag prox sensor.

Or use a HF handheld optical tacho, about $30? Then mark the old plate with new numbers, sharpie. Or 'puter print a chart?

Need "something" at least chartish, yah?

Otherwise one could be off by 1500 RPM as easily as 150 RPM.
 
The 416 is cold drawn, I ordered it from Online Metals. I thought it might of been a material issue and they sent me another piece to try. I am not sure of the hardness, I will research and post a follow up.

Mark
It is starting to sound like your material, Like I said I bought some 1/2 inch annealed material from Carpenter 30 years ago and still have most of as I heat treat it in small batches and use it for special stuff. Carpenter stainless is premium material if their annealed does not finish well, I would can imagine that brand X, maybe imported almost 416 would be really bad. With reasonably sharp tooling I can get a good finish on my slow South Bend 9C, speeds and feeds are not an issue with the 416HT I get from Carpenter. Fry and some others will sell small quantities, there is one European company selling premium stainless, I think they used to be called Schmolze or something like that.
 
Turning 416

I sent quite a bit of time turning some 416 1.25” stock. The results were some what better, but still not a clean finish. The orders come with metalurgical sheets from NAS. My original thoughts maybe when the order was pulled they grabbed the wrong material.

My tooling is Mitsubishi SCLCR 1/2” bar on a Aloris tool post. The tool post was worn to the point the holders were loose, and since the post itself was worn I replaced it instead of just buy the gibbs. I have only been running a lathe for a short period, but I must these lathe are surprisingly accurate even with some wear. These lathe must of been amazing accurate when they were new.

I run rpm up to 800 and down to about 300rpm. Feeds I tried are from 7:30 to around 10:00. The lower speed and feed did seem to improve the finish some.
 
It's actually rather cheap to add a permanent tacho to the spindle.

Right but that won't help with feed rates which is what he wants and needs.

Unlike a southbend lathe with a gearbox, the dc motor feed on an HLVH only gives 0 to 100 variac setting.

On the older ones. Newer ones give 0 to 100 settings for a potentiometer for the dc feed circuit.
 
If all else fails, grind an HSS shear tool and do a .003" DOC finish cut at a slow feed, say 35% on the Variac. Use oil. The chip should look like fine steel wool if everything is working right. The finish should look like a ground part.
 
I am not set up to grind tooling nor do I have the knowledge. When I purchased the lathe it came cemented carbide tooling. I made the decision to switch to insert tooling, to focus on learning the lathe. I do have one of the old hand held rpm tools. It has the hard rubber assortment of wheels that slip on the shaft. I bought it to use on my BP mill since it step pulley powered through a vfd. Thanks for the ideas everyone.
 
Cutting 416

0ECB2244-4244-497B-9C30-6F07C4A3423E.jpgIt finally cuts 416 like it should, it temporary until I can get all the parts together and get a break in part orders.

I pulled all the feed handles, hand wheel and drive motor, cleaned out the apron, and check for damage. The drain plug is stuck and the drive motor is the lowest point. There was no clutch drive material, and only a small amount of bronze bushing. Who ever work on the apron previously used enough silicone that the excess could of been used for implants. Thanks for ideas everyone
 
I do have one of the old hand held rpm tools. It has the hard rubber assortment of wheels that slip on the shaft. I bought it to use on my BP mill since it step pulley powered through a vfd.

I have several, non-contact electronic included.

The one I PREFER actually is an old James Biddle mechanical, constantly reading & calculating, not timed-period (have those as well..).

It gives me better sight of any irregularities whilst running.

My larger mill has a "factory" point to support an optional mechanical tacho they offered.

I've snatched-up several Stewart-Warner Marine-Diesel tacho, NOS with appropriate ranges for that eventual "permanent" use.
 








 
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