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Yooper
Apr 30, 2012



Grimey Drawer

threelemmings posted:

Hmmm aluminum frame airplanes to increase your available airforce are definitely more on the metalworking side than blacksmithing, can't help you there. You'll have to wait for our machining experts to check the thread.

Oh poo poo, wrong thread.

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Chirk Manbote
Apr 19, 2012


Yooper posted:

Oh poo poo, wrong thread.

On that note, what are all the builderbabby threads that'd be useful to someone with a mechanical job or hobby?
These are the 4 I'm following:
Tools https://forums.somethingawful.com/s...hreadid=3384038
CNC https://forums.somethingawful.com/s...hreadid=3558051
3D Printing https://forums.somethingawful.com/s...hreadid=3365193
Blacksmithing/Metalworking https://forums.somethingawful.com/s...hreadid=2905844 (the very thread you are reading)

powderific
May 13, 2004



Grimey Drawer

There's also a tools thread in AI. Obviously lots of car stuff, but general toolchat there too: https://forums.somethingawful.com/s...hreadid=2788369

Kaiser Schnitzel
Mar 28, 2006

Schnitzel mit uns






Is there a name for the fitting that would go on the end of an acme screw to hold it in place but let it spin freely? Right now I’m using a bronze bearing and the end of the thread just rubs against the wood, and you can feel a lump where the thread starts when rotating it. I’m thinking something like the pad on a C clamp? Or should I just grind the end of the thread to be more rounded?

Pics if they help:

shame on an IGA
Apr 8, 2005



You're looking for a thrust washer

Rapulum_Dei
Sep 7, 2009


Or thrust bearing.

Hypnolobster
Apr 12, 2007

What this sausage party needs is a big dollop of ketchup! Too bad I didn't make any.


If you just want to make a surface to bear against, then the mentioned thrust bearing/bushing at the tip of the acme rod (or just sitting down in the bore) would do it, or a shaft collar that bears on the bushing. If you want to actually hold the shaft in there so it can't lift out, then the only easy way is a flange bearing with a set screw (and maybe a shaft collar, depending on load and load direction)

shame on an IGA
Apr 8, 2005



Yeah flange bearing and drill all the way through sounds like the best option

Kaiser Schnitzel
Mar 28, 2006

Schnitzel mit uns






I actually made a simple jig and ground the tip into a slight cone so it wasn't lopsided anymore. That didn't fix the problem-I think either the screw shaft is slightly bent or the nut is installed a little wonky (by far the most likely option). The screw is basically a jack to raise/lower something, and the wobble was a little annoying but doesn't seem to be majorly impacting the way anything works. Stiffening up the rest of the framework seems to have helped as well. This whole project has been 'mock it up and make sure it works, and then I'll build a real one later' and, uh, the mockup works and now I guess it's the tempermanent, cobbled together, real one.

Thanks for the advice anyway! I've got plans to build a vise of some sort soon, and I'm sure I'll need something similar then.

bred
Oct 24, 2008


I like the bronze bushing but it looks like it is a through hole and your lifting loads are going into the plywood. Here's how we do that on our machines at work:

You can see the screw has been turned down to have a shoulder that delivers axial load into a bearing race.

In your case, I think cleaning up the end is fine and I'd put a washer or some other metal under the screw so the wood sees lower psi contact stress and no relative motion.

Consider letting your nut float around radially. I see two guides and a screw and, if everything is tight, you have 3 lines in space that need to be parallel. The two guides have defined your path so the nut is just providing the motion. It can float around to accommodate a bent shaft and any build issues. The errors from radial play are near zero with small angle approximation.

Here are some other configs from googling. My 3d printer does the z axis with the first config and a loose nut. Good enough to get the job done.

His Divine Shadow
Aug 7, 2000

I'm not a fascist. I'm a priest. Fascists dress up in black and tell people what to do.


Anyone recognize this chuck mount?





Looking for a "new" chuck for my lathe and this chuck looked OK and a good price. Röhm. Not seen a mount like that though, usually they just got threaded holes and you screw it onto your own homemade backing plate, not quite sure what I am looking at here.

Rapulum_Dei
Sep 7, 2009


The fact that the studs have flats on them suggests they unscrew leaving you with your threaded mounting holes...

Yooper
Apr 30, 2012



Grimey Drawer

His Divine Shadow posted:

Anyone recognize this chuck mount?

Looking for a "new" chuck for my lathe and this chuck looked OK and a good price. Röhm. Not seen a mount like that though, usually they just got threaded holes and you screw it onto your own homemade backing plate, not quite sure what I am looking at here.

DIN 55027

Looks like it was popular in East Germany. I believe you have a chuck and the back plate.



I can find some threads on PracticalMachinist where people run into them.

https://www.practicalmachinist.com/...o-lathe-163240/

His Divine Shadow
Aug 7, 2000

I'm not a fascist. I'm a priest. Fascists dress up in black and tell people what to do.


Duh oh yeah good catch, that is part of the backing plate and not the chuck itself.

His Divine Shadow
Aug 7, 2000

I'm not a fascist. I'm a priest. Fascists dress up in black and tell people what to do.


Having apart the lathe cross slide and saddle for cleaning (do that now and then I find it's needed) and I removed a few parts so I could measure them and put them in CAD for replacement making.

The half nuts are used for longitudinal feed on this lathe so they see alot of use. And are quite worn down now.







Planning to make a replacement in steel and to make the actual nut a separate part that can be replaced.

Same thing with the cross slide nut, this is a hot dog in a hallway fit at the moment.





That replacement will also be of steel instead of a single piece of bronze. I am contemplaing using acetal as material for both screws. Or maybe I will go with cast iron because it seems to be much better than bronze. When I compare the wear on the top slide and the cross slide, the cross slide is worn on both the screw and the nut. But on the main lead screw the lead screw shows very little wear, almost all the wear is in the cast iron nuts. It clearly seems to be a working solution.

I'm going to have to remake the cross slide nut entirely.

And some interesting dimensions and pitch combos on this lathe (Rexvalter VF118, made in 1950s Sweden), the main lead screw is 8 TPI but 20mm diameter. The cross slide screw is 3mm pitch but 7/16ths diameter.

honda whisperer
Mar 29, 2009



I'm about to start repairing rust on a 30 year old civic, followed by building a roll cage.

I'll make a build thread in AI when I've got more content.

Want me to throw my struggles with welding rusty sheet metal in here for your amusement?

threelemmings
Dec 4, 2007
A jellyfish!

Welding thin sheet metal is an exercise in the best of times, sounds terrible!

powderific
May 13, 2004



Grimey Drawer

I’m trying to learn how to weld while in quarantine and have discovered that different manufacturer’s electrodes work differently. Initially I had Hobart 6013 and 6011, both in 3/32”. The 6013 worked well enough—I can light an arc and weld. Still need lots of practice, but it works. The 6011 I could not get to work on any amperage with my little inverter welder. It was really hard to light and would stick constantly, enough that I couldn’t even run a bead.

Today I picked up some Lincoln electrodes, and the 6011 works totally fine. The Lincoln 6013 acted a bit different from the Hobart stuff too: seemed like the rod was a lot runnier, or at least the flux was, and the slag was easier to get off.

I’d assumed, wrongly it seems, that the rods would be about the same between manufacturers.

His Divine Shadow
Aug 7, 2000

I'm not a fascist. I'm a priest. Fascists dress up in black and tell people what to do.


Oh yes there are definitely differences between manufacturers.

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sharkytm
Oct 9, 2003

Gimme Gimme Swedish Fish...

Fallen Rib

Age/moisture is also another big factor with SMAW electrodes. New rods often weld much nicer than old stuff that's been sitting around. 6011 doesn't need an oven, and you can't bake them but if they got really wet, they won't strike for poo poo.

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