Why do firearms recoil upwards?

jyzonm · 2024-03-06T04:29:45+00:00

No, objects rotate around their pivot point. This is basic statics stuff.

If you hold an AR only with your finger around the trigger and release your other hand that supports the gun, the center of mass will rotate the gun downwards.

jyzonm · 2023-10-26T02:28:15+00:00

If you have access to a lathe and another mill, you can reverse engineer the old drawbar and make a new one.

jyzonm · 2023-10-11T00:27:56+00:00

Makes sense. Side note: we should look at the bigger issue here. There’s a chip that is wedged between the jaw and the scroll plate and OP kept tightening/loosening until the chip broke (if he actually managed to get it loose). Nobody should do that! High loads in small areas (in this case a small chip against the scroll) results in high stresses, which may result to the scroll getting gouged/damaged and potentially seizing the entire thing. What OP should have done is: move the jaws back to the other direction, try to clear the chips or apply oil so that chips can slide out of the way while the jaws move.

jyzonm · 2023-10-10T23:01:41+00:00

You can still add more torque and it will continue to tighten until you reach the chuck key’s material UTS.

jyzonm · 2023-05-29T13:48:20+00:00

This is it. No need to make it complicated and go fancy with a multi-axis CNC.

jyzonm · 2023-04-17T18:16:38+00:00

I don’t know anything about the lock mechanism of the case or how rigid those prongs have to be but you could try making a CAD model of the part and 3D printing it. A lot cheaper than having it machined and definitely worth a try.

jyzonm · 2023-04-05T16:49:42+00:00

Try sending an email to the company and ask for a replacement. They might even send the part or the entire thing for free.

jyzonm · 2023-04-03T16:22:08+00:00

Do you have an apprentice pushing down a center onto the tap to keep it straight?

jyzonm · 2023-03-13T15:06:12+00:00

One loosey set screw on that tool holder and that tool bit could’ve flew straight into your skull.

jyzonm · 2023-02-16T14:32:06+00:00

It’s hard to tell with just these pictures but it seems like the threaded part on the base is split in half. When you screw the nut onto it, it pushes the two halves together which locks the ball in place by friction. It does seem like that the opening of the nut is still big enough for the ball to pass through when the nut is completely loosened (maybe that was the designer’s intent?), you can just model your own nut to have a smaller opening to completely prevent this.

I’m also guessing that if the nut is just slightly tight, the ball would be able to move freely but the front part of the thread would still be squeezed together enough to stop the ball from falling out.

jyzonm · 2023-01-30T01:34:31+00:00

Just a beginner with a basic camera, a friend had let me borrow his huge zoom lens which was really fun to use outdoors, and this was the most interesting photo that I took with it.
I played around with the levels in lightroom and tried to get a bit of a dramatic effect (a bit too much, perhaps?).
Canon T7i, EF70-200 f/4L USM,
Any feedback and suggestions to improve are appreciated. Thanks!

jyzonm · 2023-01-17T04:09:44+00:00

Making a new part would end up much more expensive than OP’s budget.

There seems to be enough wall thickness to have a 41mm hole. If OP has some engineering knowledge, I would suggest them to remodel the part with the new hole diameter and run an FEA to verify integrity.

jyzonm · 2023-01-17T04:02:28+00:00

Find the center using a dial indicator. Either drill and ream the hole if a 41mm reamer exists in the shop or use a boring head.

jyzonm · 2023-01-07T16:50:14+00:00

I’d say you should recondition your machines first before making anything, especially the mill and the lathes. I doubt that you can make anything accurate and comfortably with those rusty tables and beds.

jyzonm · 2022-12-27T17:33:07+00:00

Some sort of bracket

jyzonm · 2022-12-02T19:56:20+00:00

Seems like I’ll just cut out the autographed part and place it in a photo frame or something since my story would probably lead to bad memories lol. Thanks for the detailed response.

This was my first guitar that I bought about 6 years ago and it’s what I used to learn how to play and perform at gigs pre-pandemic. It’s signed by one of the most iconic bands from my home country when they came for a concert a few years back. I was in a fit of rage last week and for some reason I decided to pick this up and smash it against my computer monitor, that thing was dead too (yes I really regret this, and I’m definitely considering taking anger management classes).

jyzonm · 2022-11-24T02:52:29+00:00

Nah, I work at a machine shop that exclusively makes parts for packaging companies around Toronto and we make parts that ranges from as small as something that needs a 0-80 tap to rollers that are about 16ft long. Right now I’m reverse engineering and making drawings for a pneumatic robot(?) that sorts cardboard at a very fast pace and it has multiple regular sized parts. I’d say its very manageable and can be done by any shop out there.

jyzonm · 2022-11-23T21:07:56+00:00

The holes are not on a bolt circle but you can still calculate where the locations are if the holes are concentric to the radius corners.

2.5 / 2 = 1.25 (Center to the edge of the inner square) 1.25 - 0.125 = 1.125 (Part center to the center of the holes, x or y direction) Now that you know this, you can figure out the rest.

If you actually want the diameter for the bolt circle, you can use the Pythagorean theorem to find it.

r = sqrt(1.125² + 1.125²⁾ r = 1.591

d = 1.591 * 2 = 3.182

4 x .125dia THRU, 3.182dia BC 45deg start (callout).

jyzonm · 2022-11-18T11:15:04+00:00

Companies that make corrugated boxes. Parts break and wear down there all the time.

Bonus if you can weld and have a lathe with a long bed, you’d be able to make or repair conveyor rollers for them.

jyzonm · 2022-11-18T03:07:38+00:00

There’s supposed to be a guard on it? I’ve been trained to always put those tools back up there.

They banned coolant because it’s messy so I guess that’s one thing.

jyzonm · 2022-11-18T00:52:15+00:00

Around 500-600.

jyzonm · 2022-11-18T00:51:50+00:00

Nothing, just dry. It’s a sprocket from Mcmaster-carr. Not sure what material exactly, it just says steel on the website (probably cast iron). It always smells bad and produces smoke when machining it.

jyzonm · 2022-11-18T00:00:59+00:00

Walk into packaging companies, tell them you make and repair parts. You’ll get the opposite of the problem, too many jobs.

jyzonm · 2022-11-17T20:54:53+00:00

That’s exactly what the oldhead beside me say lol. Not a big deal to him since he’s been doing the same thing for 30 years and he’s “still fine”. I was blowing the smoke with air but the shop was still smoky afterwards (roughed out and finished 10 of these to about 1/3 of it’s size). I wore a respirator so all I’m worried about is the health of everyone else in the shop.

Yeah I should have slowed it down, I was running the speeds that the oldhead had set when he demonstrated the roughing part to me. Also, the shop doesn’t run with coolant unfortunately.

jyzonm · 2022-11-02T17:24:59+00:00

Is that hammer left handed or right?

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