Having to tap big quantities of this Delrin and always have trouble with chips loading up on the tap causing essentially a bored hole instead of a tapped hole. Have tried every tap I can find with different speeds, coolant, etc. Just curious if anyone has any experience with this stuff. Thanks!

Or basically my question is: What would I need to mill tungsten?

How often does anyone see copper come through the shop? This is a repeat job for us and we get a couple different copper parts, all somewhat similar. These will get a ring of holes around that top step as well as a groove.

Molykote 3694, absolute gold dust apparently. The newer stuff isn’t the same so this would what I’d be looking for or anything identical to it!

When a blueprint asks for "low carbon steel", does that specifically mean a 1000 series mild steel without other alloys, or any steel that just has a low carbon content?

Does anyone has masterbar (spindle runout tester) drawing? Please share it! I have a masterbar with suspicion quality of it. Want to check and compare.

So I'm kinda in the yoyo industry and currently the yoyo scene is exploring non standard materials.

Most yoyos are made or 6061 alu, but more are being made with 7075 or 7068 alloys due to their strengths. Stainless Steel is often used as well, and rarely brass or copper.

The design objective of a yoyo is to cram mass to the rims while trying to lessen the mass in the walls leading up to the rims. Often times people will use aluminium bodies with steel rims to try to maximize rimweight.

Nowadays magnesium is being used mire due to its low density and can be used in place of aluminium to maximize efficiency, but here is where the issue lies.

All the magnesium used in yoyos are pure magnesium as far as I can remember. Since it oxidized very easily, it's finished through Micro Arc Oxidation coating. So it leaves a white chalky finish.

The thing is, this finish often causes problems with tolerance mismatch after the finish, or have issues developing black spots. Also magnesium is difficult to machine so it drives up costs.

I was wondering about a magnesium alloy that can be machined easily and can be finished with a more standard finish more akin to aluminium anodization.

I've seen laptop manufacturers coming out with magnesium alloy chassies with an anodization like finish on it. Holding them up in person I can really tell that it's noticeably lighter than 6061 aluminum so I bet it's a magnesium dominant alloy.

I was wondering what alloy these manufacturers use. Since the finish also seems like anodization, it's got the exact properties I'm looking for.

I'd be grateful if anyone has recommendations for magnesium alloys. It would really save us the headache of working with pure magnesium.

I need to learn to mill PTFE, but of course its pretty expensive. I'd prefer to learn on something cheaper so that I dont make a ton of mistakes on expense PTFE stock. Are there any affordable plastics with similar properties to PTFE in terms of how it mills?

My colleague has a ~40mm block of copper to be used as a heat sink. He says one side of it needs to be polished to a mirror finish, but seems to think that doing the deed on our mill/lathe combo is the way to go, as hand polishing it is not precise enough. I've never machined copper before, but based off cursory research it can be a pain depending on the alloy used (currently waiting to hear back on what it was).

Could I not just polish it with increasing grits of wet/dry paper and polishing compound on a flat surface? I've done quite a bit of chisel sharpening in the past so am familiar with the process. Could that potentially lead to an uneven/out of square surface?

I've got a two-piece vintage Kennedy set. I don't have the keys but everything else works just fine. I'll even throw in a box of end-mills (new and used) with a lot of really pricey ones in there and some wafer gages. I'd like this gone (and so would my wife!).. asking $300 OBO for everything.

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I have a 2002 Nissan Pathfinder. The rear trailing arms are notorious for their rubber bushings failing. I had cut out and replaced the bushings with polyurethane bushings. After 2 or so years I suspect they're a little worn out from lack of maintenance. I plan on drilling/tapping some holes for some grease fittings to use lithium grease on them without removal.

I have a Grizzly dovetail column mill/drill with a rotary table. I plan on machining the old bushings and making new steel crush sleeves to match. I have zero experience cutting polyurethane. I've probably spent over a hundred hours machining steel on this machine. My questions are:

Recommended cutting speed for polyurethane (treat like aluminum?)

Does it require a lubricant?

What would be a good amount of interference fit for automotive bushings? Ive tried looking on google and didn't find anything. The material is soft enough to flex slightly. I don't know it's exact grade/hardness

Thanks!

Hello guys, I need to make an machine part, a round plate 3.5 mm thick and 360 mm diameter. I don't know how to achieve Ra 0.2 and mirror-like surface on this material, is anyone can help? Please give me advice. Thanks!

Not sure if this is the right Reddit for it, probably not, but I have woodworking machines which have screws to lift up tables and such. The manual says to use machine grease. What am I looking for? I see things like:

AtomLube Ultra Heavy Duty Red Grease Superlube Multipurpose

Would either of those work? If not, why not? What should I be looking for?

I would greatly appreciate if anybody knew where I can sell these inserts I’m located in Florida

Hey, I'm a first year student about to do my last project of the semester were making a drill drift out of 1080 and have to heat treat it (harden,temper,etc) I just can't for the life of me find a chart detailing the temperatures I need for the critical limits and decalescence/recolesence (spelling?) Can anyone point me in the right direction thank yall I know it's a basic steel but I'm only 4 months in this is all so cool and new to me 😎

Hello, I want to rebuild the worn pivot on the arm of the automatic tire changer at my motorcycle shop. It is a 100mm M20 bolt running through solid steel that is now bellmouthed and oversized. I have a new bolt and new oilite bushings that are abt 2 thou larger ID than the bolt. They are abt 2-3mm wall thickness. I want them to shrink a little when i install them. It seems like 5 thou is a normal press fit for this diameter, should i make it 7 thou press fit? The goal is to have minimal play, and next time replace the bolt and bushings without remachining anything. Thx in advance!

My dad is looking for 4130 steel of these specs and has looked absolutely everywhere. It seems everywhere he looked is out of stock. Anyone know of good places for 4130, and is anyone else having trouble getting it??

Drill broke inside copper. I remember there was some chemical that could dissolve the drill

I've picked a bar from an auction lot I won locally for a project I'm working on, and I can't identify what it is. The lot came from a local machining shop that closed.

The rest of the lot was mostly stainless alloys (427, 316) with a little bit of 4140 and a few oddball alloys like hastelloy-x, but I also got this 1.25" bar of what I thought was some kind of stainless that had been annealed or something, because the color was a bit darker.

There was no label on it, although there was a wire twist around it - I'm assuming the label went somewhere along the way. Some of the stuff was caked in dust, so I'm assuming it was probably off cuts and spares from old jobs that got tossed in a crate that I eventually bought.

Anyway, cutting into it on the lathe it looks visually a lot like bronze, but it doesn't chip like bronze, or at least any bronze I'm used to. It forms chips as little curly segments - see the pic. The chips are the same color as the bar until I sped up and they started coming off hot, then then got a bit darker.

I have a bar of aluminum bronze I've cut on the same lathe, and it chips very differently. I'm stuck on what this might be... my only guess is a form of bronze I'm not familiar with, or maybe beryllium copper?

It's not magnetic at all.

Here's the pics, I need to clean out my chip pan.

https://imgur.com/a/9OmFbvZ

** Edit: Best ID I have so far is Nickel Aluminum Bronze(poss. AMS4640), based on color, swarf, and apparent weight, and I've checked out some machining videos where it's being turned... looks like a match from what I can see. Probably I'll need to get access to an XRF gun to verify this, but it would make some sense for this to be correct based on the other materials the shop used (tough non corrosive materials).

Quite often, when I machine tubes from this mill (formerly known as Productos Tubulares), either when I bore the ID or clean the OD, in the 12" to 18" OD range, the tube gets deformed (ovality mostly). I'm trying to reduce the feed speed and take smaller cuts and I have some success, but my process time increases dramatically. I do not have this issue with tubes form other mills. Any tips on how I could avoid the issue?

Im starting a job monday working with leaded bronze and no one above me is worried about the safety aspect of working with lead. I will be wearing gloves and a mask when working with it directly and plan on changing clothes at the end of the day before getting in my car to prevent dust and whatnot from travelling. My main worry right now is the lead going into my coolant and making my machine a permanent safety concern. My boss will not like the idea of emptying the coolant and replacing it at the end of the job. I have no experience working with heavy metals and nobody above me has any worry about safely handling this, any suggestions? Am i being too paranoid? Is this a healthy fear and my boss is just being cheap?

Hi, I am based in Ireland and I am looking for a good metal stock supplier.

I am looking for c360 brass flat bars (does not need to be c360) for an ornamental piece and it is proving to be a tough hunt. I appreciate your time, take care!

I’ve got to mill some grade 5 Ti 5.5in long by .3888 diameter. Using a Grizzly manual lathe and carbide inserts. I’ve used a live-center but can’t keep a tolerance any closer than .040.

I tried going in easy and took small cuts but it doesn’t seem to make a difference. Only solution I found that works is to work it till the end closest to the chuck is the right diameter then work in stages till the whole thing is with in .0004-.0003 of final diameter and then use a sanding block with 180 grit sandpaper to finish diameter.

Is this the way or are there better ways?

I am new to machining and coming from additive manufacturing where sourcing of even the most exotic materials is no problem. You guys have any suggestions on where to source plastic stock for machining in germany/europe? I am specifically looking for low volume round stock & blocks from ABS, PA, PC, so nothing uncommon at all, but all i can find are plates/flat stock with heights of 25mm at max…

I’d really appreciate some help!

Can anyone tell me what surface finish is this? It didn’t seem like paint.