[Newbie] Jwest7788 Beginner Machinist Questions Thread

[jwest7788]

Hey all, Just signed up yesterday.

I've acquired a mini mill (craftex) and a B2227L 10X18 Metal Lathe.

As I am new to both tools, I figured I would start my own thread to pack with a series of questions as they inevitably unfold one by one in the coming weeks.

Firstly, I'm currently focused on the lathe, and learning how to use it.


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Background Below:
TLDR: $650 10X18 lathe + Enough tooling and accessories to keep me going for awhile.
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I posted an ad on Kijiji (Canadian Craigslist, but way better, lol) looking for a mini mill. Low and behold, someone offered one up. It was essentially new, used for a single project (make four replacement aluminum wheels for RC car) --> Due to the nature of wheels, it came with a rotary table. No tooling $400.

Updated the Kijiji Ad, "Have a mill, looking for a mini lathe"

Got a reply, someone's father passed away, B2227L 10X18, some tooling, $1400 firm. Kindly told him I was looking for a used mini lathe, so this was clearly outside of my budget. Kindly thanked him for his time.

Few weeks later, still hadn't been contacted with anyone selling a mini lathe, but had saved up a full $650 to buy one new. Figured it was a long shot, but emailed the above gentleman back explaining that I planned to buy a mini lathe the next day, but figured I would reach out to see if he could move on my low low low ball.

The look on my face when he called and said "Sure, I'll take your offer. I know it's a steal of a deal, but because you were so polite, I feel like I'm helping you get a leg up in metalworking."

Thought that was cool enough, until I showed up, and he had a drawer full of tooling, centers, chucks, collets, change gears etc. etc. He even through in a custom built bench with chip collection, and a green wheel bench grinder. $650!

Pic attached of one of three drawers with stuff in it.

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END Background
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Question
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The lathe has these little ball bearing spots throughout. Are these places for lubricating oil?
Any preference for oil type?

The change gear axle bolt thing has one of these ball bearing spots too, it's also cracked and very very slowly leaking oil. What's my action plan for this?




Should I change the oil in the headstock, or don't worry about it?

Having troubles with threading, still learning all the details at the beginner forum. When threading my own stuff, it doesn't really matter which mm pitch I pick, as long as it's the same on both ends. The issue is if I want to match the thread of something else, correct?
--> Is there any way to convert this to Imperial? The largest learning curve for me is the metric stuff.

Alot of the tools are missing their brazed carbide insert. Is there any benefit of keeping these broken tools?
--> What steel are they made of? (Appropriate for turning them into little stock rods? "For science")

When feeding the tool into the part, is it better to use the compound to feed, or the Y access feed?



Thanks All! Glad to be part of the new community!

 

[T Bredehoft]

Last question answered first, compound is for angles other than y or z, such as threading where you advance the tool parallel to one side of the cutter.

Lathe tools without carbides. I've never found a use for them, but if you need small pieces of soft steel, there they are.

The bbs are for oil, you put the tip of the oil gun (you'll need one) against the bb, compress the spring under it, and give it a shot of oil. {look for one of several threads on these oil guns}

 

[hman]

Congratulations on a very sweet deal! IMHO, the original $1400 would have been a bit high, as Busy Bee has them new for $1599:
http://www.busybeetools.com/products/lathe-metal-10in-x-18in-3-4-hp-craftex.html
[Of course, that's without a lot of tooling, so I could be way off base!]

To answer at least some of your questions ...

You'll hear lots of debate about oil, but (IMO) just about any non-detergent motor oil will do. Detergents hold water, which you don't want happening in a machine tool.

Re the crunched oil cover - leaking isn't that big an issue - the oil film between the parts is what counts, and it won't leak away. If you want to replace the cover, you can look for "Gits" on the interweb, or else go to McMaster-Carr:
http://www.mcmaster.com/#oil-cups/=wuqm2s

Headstock oil - maybe. How does the existing oil look? If it's clear and clean, I wouldn't worry. By the way, I use ATF in my old Grizzly 12x24.

Inch threading - Somewhere in your collection of change gears, you should have either a 127 tooth and 120 tooth gear (often combined on a bushing), or possibly a 91 tooth - 86 tooth. Either of these sets will "covert" between metric and inch. You'll need to check your owner's manual, or at least look for an inch threading chart label somewhere on the headstock. Did the lathe come with a manual? If not, you can probably ask Busy Bee for one, or else find one someplace else on the interweb.

Carbides sans carbide - as T Bredehoft said, they're generally pretty useless as cutting tools themselves. I have heard of folks melting the braze to remove the remaining carbide, then using the tool to hold replaceable carbide inserts (drilled & tapped for the special mounting screw).

Compound - as T Bredehoft said, it's generally better to use the cross slide. Of course, for every rule there's exceptions ...
(1) Set the compound at 29.5 degrees when threading, and by using it to advance the cutter, you're reducing chatter by only cutting on one face of the thread at a time. The cross slide (with zero appropriately set) is used to back the tool away from the work on the "return stroke," then back to the same place (zero) for each cutting pass.
(2) By setting the compound to a very shallow angle, you can advance the tool in very small increments to make fine adjustments to the diameter of your part. At 5 or 6 degrees, you advance the tool inward by .0001" for every .001" movement of the dial (OK, .003mm for every .03mm advance). [The sine of 5.7 degrees is 0.1]

Best wishes ... now make some chips!!!

 

[jwest7788]

Thanks guys, Really appreciate your tips!

With regard to the manual +/ inch threading. I have a digital copy of the manual, but it's clearly a "written in china, and once reviewed before approval" type. (Basically no instructions beyond what I figured out just standing there.)
Here's the chart for threading on the front. (Not my image, but same chart)
Not sure I understand about the

Inch threading - Somewhere in your collection of change gears, you should have either a 127 tooth and 120 tooth gear (often combined on a bushing), or possibly a 91 tooth - 86 tooth. Either of these sets will "covert" between metric and inch. You'll need to check your owner's manual, or at least look for an inch threading chart label somewhere on the headstock. Did the lathe come with a manual? If not, you can probably ask Busy Bee for one, or else find one someplace else on the interweb.

Haha, I looked up the chart on the front of my lathe and took a closer look. I now realize how horridly I overlooked the part I needed. I assume 1/n is turns per inch?

(Not my pic, same chart though)


Can someone confirm the two charts in the bottom third?

Thanks agian all!

 

[hman]

First off, you really should try to get a better version of the manual. Would Busy Bee do you any good? If not, look around Grizzly, Enco, etc. for the same model (10x18) lathe (with a different color scheme, but controls located in the same places). Grizzly's manuals are generally pretty good.

As for your big chart ...
The top section shows gear setups for metric threading, as you've figured out.


The next section shows inch thread setups. You figured this one out correctly.


The bottom panels are curious. They might both refer to feeds when using a different laver on the carriage. The one on the left looks like it says "m <pi symbol>", but that might be scuffed paint. Can you read yours? In any case, I don't see where a carriage feed as fast as 1.25mm per turn would be very useful, and I don't want to go out on a limb.


The one on the lower right does look like horizontal feeds, especially given the pictorial (Xmm/turn).


... anyway, that's my best guess. Best wishes!

 

[jwest7788]

Thanks John.

Checked mine last night, Can confirm the lower left chart is m[PI]
0.2 would take forever on that thing... Maybe for finishing?


Thanks for everyone's help with my initial set of questions. I believe I understand each much better now.


New Questions for discussion!:
I have a small case of el cheapo looking carbide brazed cutters, they appear new and un-used (Paint on cutting edges still)
--> I notice the carbide doesn't have a cutting edge, missing the side and front relief, rake, and chip breaker. Should I hit these with the green grinding stone to sharpen them up before use, or use the un cut 90 degree edges? (Not sure what the standard process is for these)

1/4" lathe tools in this thing. What are the risks, benefits and things to watch out for? (I have dozens of them that came with)

While experimenting with threading, the 29.5 degree thing finally clicked as to why it made sense, but I found myself with a new problem:
When the compound is at the proper angle, my tooling isn't. Does it matter if I secure the tool post so that the tool is perpendicular the stock, or is it proffered to have my tool post square to the compound, but with the tool cut so that the tool shaft is parallel the compound, but with the cutting tip is perpendicular?

I'll preface the below with: I plan to buy some proper stock, but blew my whole budget on the machines, so i'm out of luck for that for two-three weeks, but itching to start making chips
Rail spikes. The smiths over at anvil fire note that the "HC" marked spikes are 0.30% carbon. These would turn to Aprox. 4" X 1/2" rods if turned down. Besides basic practice, worth my time at all?
Old bolts. Worth practicing turning with?
Rebar?

 

[X-RAY]

i practiced alot of threading on old pvc pipes, cuts easy and i live beside i plumbing shop so theyre free. just make sure you get the supply ones. should be easy to find scraps for you.

 

[hman]

Brazed carbide ... ??? The only thing I can contribute is that few of them have chip breakers.

1/4 inch tooling ... good! As many others have pointed out, and I agree, it's an OK size for your lathe. You could go to 5/16 or 3/8, but with 1/4" you don't need to grind away anywhere near as much metal to get the shape you want. If you're concerned about chatter, just don't extend the bit out too far out from the tool holder.

Regarding the 29 1/2 degrees ... first not that some compounds have "odd" protractor scales on them, and the setting you'd use would be 60 degrees, rather than 30 degrees. Anyway, you grind the threading tool to have a 60 degree point (with a very slight radius). Then use a "fish tail" to set the rotary position of the tool holder atop the compound. If that's unfamiliar territory, be sure to ask, and I'll try to dig up a photo.

As for railroad spikes - do-able, but rounding off a square is hard on the lathe tool. Carbide tools are especially vulnerable to damage when doing interrupted cuts.

+1 on X-RAY's advice to start learning on PVC pipe!!!

 

[jwest7788]

Brazed Carbide = Carbide tipped tools where the carbide block is brazed on, not the index-able kind. (Not sure if these have a more common name I am not aware of?)

I'm finding that the finish I'm getting with Carbide tools is kind of.. "tear-ey" anyone comment on that?

Will track down some PVC, that sounds like a good plan.


When Threading, is it better to go slower, or faster?
--> Slow seems to be most easily controlled, and I am afraid of running my tooling into the 3J-chuck, but fast actually makes threads, lol.

Anyone have tips on what size to bore and turn the stock to when planning on threading the peices together?
--> I've been reading lots, but realize it's actually a math item. It should be, final size + Thread depth for both the bar and tube?


Pics of my (currently messy) setup:

 

[T Bredehoft]

OD Threads. A one inch 8 pitch thread has an OD of one inch. No calculation needed. You take away metal in the threads until the pitch diameter is reached. I use a table, dont' bother using RAM to remember them.

Threading speed. go a speed you are comfortable with. I learned, with high speed steel, running really slow. Later, when in production, with carbide tools I was threading around 500 rpm on 1 1/4 diameter stock. ( I had a quarter inch wide gap machined in which to stop the thread.)

ID Threads, use a table to tell you the ID for an internal thread, again, no point in trying to remember them all.

Don't have a table? Google it. Print it out. Nail it on the wall.

Don't have a means of measuring Pitch Diameter? use a nut, but remember quality may vary.

Looks like a good start on a hobby shop. I'd advise against too much audio in the shop, though. You want to become familiar with the sound of metal working so you know when something isn't right. For instance, when I'm turning something (anything) on my lathe, I can hear a rhythmic pulse, once every two seconds or so. One of the gears in the head is out of round, (or something). I've got to find out what's wrong and fix it. It shows up as a ragged cut every 1/16 of an inch or so.