What did you machine today?

[Bented]

Not bad really, used a 10th reading dial bore gauge, the machine will hold .001" all day long once it warms up.
Also pressing bearings into thin walled plastic has little effect if the bore .0005 small.

These are not aircraft components.

[Cenedd]

Tim The Grim Nice work. Looks good and it's nice not to chuck things away as you're 'supposed' to. I only have a micro torch....but fortunately I work in IT which is perhaps the only field that a man can boast the "My one's smaller than your one!" and it be a good thing!

[Ironbearmarine]

A while back I bought a self igniter Presto-Lite Turbo Torch and acetylene tank from a guy on CL. I think I paid $125 and was happy.
Late last Summer it coughed up a “hairball” of some sort that went sparking to the ground during a silver solder preheat. After that the torch flame was
always too diffuse and actually melted the end of the brass tip a few weeks back. The prices online for parts and tips are ridiculous so today I machine down the old 7/16-27 threaded tip and made a steel tip that fit on the threaded end. I’m happy again.

Achhhh! I would rather saw my fingers off with a dull car jack then use a turbo torch! Maybe my ears are too sensitive, but turbo torches put out a whine that is so painful to my ears that i have quit shops that required their use. I prefer the good old Prest-o-lite passive air mix torch of mid 20th century. Still have one and use it fairly frequently.

[Tim Clarke]

One of the many things on my ‘roundtuit list was a scope mount for my childhood Mossberg single shot .22 Ya I know the 4-16x scope is a overkill, but it’s the only one I’ve got with a focus feature.

[jmm03]

nice job on that mount, as seemingly crude as the old mossybergs appear, they can be surprisingly accurate. I have an older 144. Jim

[briuz]

I finished machining the next version of the turret for my CNC lathe. The first version of the turret took me over a week using a manual milling machine. This version took little more than a day using CNC and a manual milling machine. At some point in the future I'll be able to mill one out in less than a day.

[Dan Dubeau]

Nice job on the turret Briuz, looks great!

You should start a thread for your CNC lathe build. I can't speak for others, but I'd love to follow along on the build/upgrade process. I'm sure it would be a great addition to the forum, we can never have too many build threads.

[briuz]

Thanks! I took what pictures I have, added some explanations, and posted it here: https://bbs.homeshopmachinist.net/fo...e-build-thread

Nice job on the turret Briuz, looks great!

You should start a thread for your CNC lathe build. I can't speak for others, but I'd love to follow along on the build/upgrade process. I'm sure it would be a great addition to the forum, we can never have too many build threads.

[The Metal Butcher]

Did some of my longest lathe work ever yesterday.

Still building the swivel joint for a 4wd human powered vehicle for my senior design project.

Learned a few things. One is to not make the steady band too close to the chuck, as you will have the chuck's clamping influence. Then your steady rest will follow the egg, and so will your bore.

The second is that infrared thermometers lie like sin on aluminum. I wanted a 3.5-4 thou shink fit, heated to 7 for 3 clearance. Well we waaaaay overheated it. Way. My friend I was working with stuck the piece in pretty fast, as I told him he needed to be quick, but it went in too far. The tube was heated so much the 20 thousands shoulder wasn't enough to stop it. So as it cooled it bulged out. That and the temper is ruined anyway. That and it's 8" too long anyway. Soo, I'm gonna reclaim my inner bits, cut the tube down and re-bore it. To avoid the same mistakes I'm going to buy a temperature crayon and use spring calipers to check when it's on dimension. In addition, I will have a clamping ring to ensure that the piece doesn't go inside too far.

This buggy is going to have 50 times the machining of previous years...

[Cenedd]

The Metal Butcher A two-part axel with machined areas for bearings?
Infrared thermometers lie like sin on a lot of things....at least the ones in my "Ooh, I'll have one of those for less than ten bucks!" budget do! Sometimes it's because I reckon they're effectively averaging what they see. Reflectivity can be an issue too.
Get more than one temp crayon if they're not horribly priced. That way you can have one that goes off before you get to your desired temp so you know when you're approaching it. I've not played with temp crayons but the principal (at least in my disturbed head) seems similar to steaming milk when your wife demands complicated coffees! I have one of those temperature stickers on the jug a bit like you get on a tropical fish tank. When the first one lights up you back off because it'll coast up to the second where you want to stop. Probably less lag when it's directly attached to the metal you're directly heating....but if they're cheap enough

[Bented]

The turned areas are bands for the steady, tubing is not manufactured round enough.

Why the chuck on the tail stock end? A plug would be much easier.
A plug used for banding a tube prior to a steady.

[The Metal Butcher]

The Metal Butcher A two-part axel with machined areas for bearings?
Infrared thermometers lie like sin on a lot of things....at least the ones in my "Ooh, I'll have one of those for less than ten bucks!" budget do! Sometimes it's because I reckon they're effectively averaging what they see. Reflectivity can be an issue too.
Get more than one temp crayon if they're not horribly priced. That way you can have one that goes off before you get to your desired temp so you know when you're approaching it. I've not played with temp crayons but the principal (at least in my disturbed head) seems similar to steaming milk when your wife demands complicated coffees! I have one of those temperature stickers on the jug a bit like you get on a tropical fish tank. When the first one lights up you back off because it'll coast up to the second where you want to stop. Probably less lag when it's directly attached to the metal you're directly heating....but if they're cheap enough

You can see how it works here. The outer tubes are 3x.125" aluminum. Then the blue plug is 6061 as well, though it was decided to shrink fit it vs weld it. The red shaft is a 4140 prehard. The bearings are R22 ball bearings, with a spacer (green). They are secured with a #7 bearing locknut (not shown). Those are pressed into another piece of 6061 (purple) which is a sliding fit into the front outer tube. The front and back half are secured with a 1/2" pin. The idea was to have a rigid rotating joint that could be rapidly assembled and secured, while leaving as small of an area as possible for dirt and crap to get in. This is what I came up with.

At $15 each my budget doesn't allow many. But since I will have so many more ways to check it now I think I'll be ok. Water will be my warning "crayon".

Thanks for the advice.

The turned areas are bands for the steady, tubing is not manufactured round enough.

Why the chuck on the tail stock end? A plug would be much easier.
A plug used for banding a tube prior to a steady.]

Well Bented, frankly it's because I don't know what I'm doing, not like you do. I only have one year of appropriate training in a HS class, and frankly I was already above that level at that time. For everything else I'm self taught.

I'm not familiar with these plugs. Are they just straight with small shoulder on them? Does my tube end need to be square, or can they tolerate a saw cut? How round does the ID of the tubing need to be? If it's not round, will they chatter? What advantages do they serve over a tailstock chuck besides not deforming the material? Can you give some recommended dimensions?

TIA.

[Bented]

You are merely creating a band for a steady on mill finished tube, very low cutting forces so a tight plug is not required.

As you have certainly found, the tube ID is often not concentric with the OD which presents a problem, turn a plug that is (the larger the tube the larger the error) slightly smaller then the ID, say .025" per side. Place one end of the part in the chuck and the tail stock end lightly snugged with the plug.
Place a dial indicator where the band will be cut then tap the tail stock end in with a soft hammer until the run out is within the error of the OD of the tube, tighten the tail stock and check the indicator. this may take a few attempts.
When the area where the band will be cut is to your liking dust it off, friction between the plug and the work will be sufficient for a band if you do not get greedy.

If the saw cut end (virtually all of them) is off this is unimportant as the position of the band has been fixed.

I use an indicator on both ends.


You are doing excellent work, keep it up.

Roughly like so.

[The Metal Butcher]

Hmm. Ok. I'm following you. I may try that sometime.

So if your saw cut was at an angle, it seems like the plug would cock off to the side. Which is where you tap it back in. So I guess for a reasonably good saw cut with the aforementioned wiggle room, you could tap it home pretty easily. Gotcha.

You are doing excellent work, keep it up.

Thanks mate, that means a lot!

[Bented]

Try not to let saw cuts get wildly out of hand.
However as long as the spot on the part that you are banding is where you want it this is all that matters for this operation.

If very close concentricity between finished bores and rough OD's is required one may turn a plug on the chuck and tail stock ends and hold the parts between them, sort of like turning between centers.
POM parts with finished bores turned on aluminum plugs, only friction keeps them from spinning, do not get to greedy (-:
https://bented.smugmug.com/My-First-Gallery/i-X6fsCw9/A