Topic: DIY Lathe Steady Rest (Read 10551 times)

HiProfile · « **on:** January 17, 2012, 11:48:05 PM »

I need a steady rest that's fairly thin, uses bearings, and can be swung open to let the work piece through. The primary work is for machining fuel injector restrictor caps off. Denso and Bosch EV14 (Injector Dynamics style). I settled on a design that opens from 0.1" to 2.5".

I started with a 1/4" steel plate, cut a hole with a centerline matching the lathe, then did a lot of math to figure out where my holes went. I used a crankshaft degree wheel to find the 120* angles needed for 3 bearing support centerlines, then made the arms out of aluminum. The center hole of the pivoting arms is 1/2" for a 1/4" screw, which is how they can be adjusted for size. The base is bolted to more aluminum (mostly to not damage the lathe ways), which is connected to a steel bar by a 1/2" threaded rod that clamps it on.

It's only to keep the injector from wobbling when clamped loosely, so I didn't need it very heavy duty. BTW this was all made with a HF drill set & tap set, a HF belt sander, a $10 drill press, and a Milwaukee sawzall & chopsaw.

Rusty? Yes, so FUCK YOU.

92CXyD · « **Reply #1 on:** January 17, 2012, 11:53:45 PM »

Looks good.

Passenger · « **Reply #2 on:** January 18, 2012, 04:08:38 PM »

Where are the action shots?

HiProfile · « **Reply #3 on:** January 18, 2012, 04:55:44 PM »

Your mom was camera shy.

The lathe is at my grandma's house, it's 5* out, and I'm off tomorrow. If I remember my camera I'll get some soon.

patsmx5 · « **Reply #4 on:** February 13, 2012, 08:14:39 AM »

Quote from: HiProfile on January 18, 2012, 04:55:44 PM

Your mom was camera shy.

The lathe is at my grandma's house, it's 5* out, and I'm off tomorrow. If I remember my camera I'll get some soon.

Fucking OWNED!!!

But seriously, that is fucking sick. I am 100 thousand percent building one just like that for my lathe.

HiProfile · « **Reply #5 on:** February 15, 2012, 09:17:06 PM »

It works great. The hardest part was the placement of holes. If you use the tensioner you can forego a lot of the work.

Only 2 things I'm changing are adjusters behind the bearings (think manual engine/pulley tensioner) that can swing out of the way, and extending the base rearwards so the carrage can get closer. ATM the carrage has long feet that stick out and hit the base.

FYI if anyone uses it on EV14's, beware they use very hard SS. I was using Kennematl carbide blanks and each was dull after a dozen injectors.

patsmx5 · « **Reply #6 on:** February 17, 2012, 12:47:51 AM »

I have had luck using dark cutting fluid for saving carbide bits when machining SS. Are you using any?

HiProfile · « **Reply #7 on:** February 18, 2012, 12:04:51 AM »

I was using what my grampa left in his garage after he passed. All I could find was a bottle of power steering fluid next to the lathe, so...

I also don't have anything atm for sharpening the carbide. What's the best way? I recall reading there's a special type of stone used for carbide.

patsmx5 · « **Reply #8 on:** February 18, 2012, 05:44:17 PM »

I've never sharpened carbide inserts. I use cutting fluid to make them last a while if I need to haul ass on something. I use a diamond ground HSS bit if I need a very sharp cutter for an awesome surface finish. So maybe rough out a part in carbide, finish it with HSS if needed.

Oh, I meant I use heavy thread cutting oil on stainless steel. It is the shit, give it a try.

HiProfile · « **Reply #9 on:** February 19, 2012, 01:17:02 PM »

Quote from: patsmx5 on February 18, 2012, 05:44:17 PM

I've never sharpened carbide inserts. I use cutting fluid to make them last a while if I need to haul ass on something. I use a diamond ground HSS bit if I need a very sharp cutter for an awesome surface finish. So maybe rough out a part in carbide, finish it with HSS if needed.

Oh, I meant I use heavy thread cutting oil on stainless steel. It is the shit, give it a try.

I'm not sharpening bolt-on inserts you buy as a 10-pack, I meant tool blanks that have carbide brazed on. I'll probably just get more bolt-on inserts for the holder I have. Even at 10 injectors per edge, I'll have 6 edges per insert at ~$3 per insert. I'd presume the specialized SS inserts I'm looking at will last much longer than the old one I found in this holder.

In any case, I'll try to get some heavy thread cutting oil and a few acid brushes next time. There's just a lot of problems keeping me from working on it often.

PhilStubbs · « **Reply #10 on:** February 19, 2012, 01:37:36 PM »

I took a lathe class about 10 years ago. I don't remember using any special grinding wheels for sharpening the bits.

HiProfile · « **Reply #11 on:** February 19, 2012, 01:55:42 PM »

I might just have to get a high-end grinder & dressing tool for the stones. I've always wanted one anyways. The $20 ryobi x-mas special I have now vibrates like a monster dildo.

Passenger · « **Reply #12 on:** February 20, 2012, 01:05:22 PM »

Quote from: HiProfile on February 19, 2012, 01:17:02 PM

Quote from: patsmx5 on February 18, 2012, 05:44:17 PM
I've never sharpened carbide inserts. I use cutting fluid to make them last a while if I need to haul ass on something. I use a diamond ground HSS bit if I need a very sharp cutter for an awesome surface finish. So maybe rough out a part in carbide, finish it with HSS if needed.

Oh, I meant I use heavy thread cutting oil on stainless steel. It is the shit, give it a try.

I'm not sharpening bolt-on inserts you buy as a 10-pack, I meant tool blanks that have carbide brazed on. I'll probably just get more bolt-on inserts for the holder I have. Even at 10 injectors per edge, I'll have 6 edges per insert at ~$3 per insert. I'd presume the specialized SS inserts I'm looking at will last much longer than the old one I found in this holder.

In any case, I'll try to get some heavy thread cutting oil and a few acid brushes next time. There's just a lot of problems keeping me from working on it often.

What style insert are you using? Pretty much all we turn here is SS so I can likely make a good recommendation for you. But before that I can't stress enough, when you are cutting SS, cutting oil matters big time, what are you using?

HiProfile · « **Reply #13 on:** February 20, 2012, 06:31:43 PM »

Quote from: Passenger on February 20, 2012, 01:05:22 PM

What style insert are you using? Pretty much all we turn here is SS so I can likely make a good recommendation for you. But before that I can't stress enough, when you are cutting SS, cutting oil matters big time, what are you using?

The oil is called "Not The Right Stuff". $:-\$ It's been a decade since I used a lathe, and it was high school where they didn't really know what to teach us.

The carbide is Toolmex/TMX NC3120, TNMG style. I've seen people post they cut better than some Kennametal for less money. http://www.ebay.com/itm/160671055955

Passenger · « **Reply #14 on:** February 20, 2012, 07:50:56 PM »

Do you have to use a TNMG? Can you switch to a CNMG?

I'm not a fan of Toolmex stuff, particularly for stainless, yes they are cheaper but I had a insert drill body fracture at recommended speeds and feeds from those guys

HiProfile · « **Reply #15 on:** February 21, 2012, 12:29:31 AM »

To boil it down - I have hard metal on a hard to hold/steady workpiece and limited to cutter size/style. I'm stuck making multiple finish-type cuts due to everything, if that helps. All I want is an insert that works. I'm not doing a million cuts, maybe 100 a month.

It's a South Bend 9", and came with a modified TNMG holder (~3/4" milled to ~1/2"). I'm stuck because the tool post/turret on this lathe is set too high for anything but 3/8" tool blanks, or this milled TNMG holder. The TMX are on ebay for $23 for 10, and I'll never be able to take much off the injectors per pass to ever break an insert.

I guess a better question to ask is can the tool post be lowered, or swapped out for a lower tool post?

Passenger · « **Reply #16 on:** February 21, 2012, 02:26:26 AM »

Throw a picture of your crosslide and tool post up. My guess is you could throw on an Aloris or something of the like and stop hating life. I'm a bit out of touch with manual machines these days

HiProfile · « **Reply #17 on:** February 21, 2012, 12:16:18 PM »

This vid shows the same type of tool post, but it's not the one I use:

1956 South Bend Lathe 9"

IIRC this is what I use, but I'm located 25min from the lathe so it will take a while to get actual pictures. I apreciate all your help so far.

Passenger · « **Reply #18 on:** February 21, 2012, 04:23:46 PM »

Yeah looks like it is just a center post, no reason why you couldn't put a different block on there.

HiProfile · « **Reply #19 on:** February 22, 2012, 03:24:54 AM »

Great. When it warms up some I'll start fucking with it.

BTW why do you recommend going with CNMG? TNMG would give me 50% more usable edges.

Passenger · « **Reply #20 on:** February 22, 2012, 12:55:22 PM »

Quote from: HiProfile on February 22, 2012, 03:24:54 AM

Great. When it warms up some I'll start fucking with it.

BTW why do you recommend going with CNMG? TNMG would give me 50% more usable edges.

Useable edges is only good if the edges last a long time, if they don't, like in your situation, it just means you get spend a lot of time fucking around with shitty tool life and swapping inserts. TNMG geometry is a lot less universal then CNMG.

CNMG is likely the single most common rough/finish insert out there, which means everyone puts the most amount of work to making the "best" CNMG inserts. I think the Iscar CNMG inserts we use (ic907 grade and TF chipbreaker) are only about $8-9 per insert, and the tool life is awesome.

HiProfile · « **Reply #21 on:** February 24, 2012, 03:11:18 AM »

I spend FAR more time traveling to the lathe itself than I'll ever spend changing an insert. I also don't have a digital readout, so no re-calibrating/probing. I estimate I'll average less than 3 linear feet a month, each pass removing a few thou thickness. They're just not easy cuts due to how hard injectors are to keep steady.

That said I'll just ask about oil. What would be my best bet if I'm limited to brush-on application?

Passenger · « **Reply #22 on:** February 24, 2012, 02:39:28 PM »

Quote from: HiProfile on February 24, 2012, 03:11:18 AM

That said I'll just ask about oil. What would be my best bet if I'm limited to brush-on application?

Something meant for high pressure cutting. Regular cutting oil can work, but never anywhere near as well as high pressure cutting oil, there is a BIG difference. At most industrial supply you can get some of the high pressure drilling and cutting paste from a mfg like Walter.

If you are lazy just get some regular old Relton in the Yellow can, (not green, that shit is for aluminum).

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Author Topic: DIY Lathe Steady Rest (Read 10551 times)