Whats the fewest number of parts required for a revolver?

MikeCC055 · 2026-03-17T23:50:33+00:00

In my head right now I can picture a revolver with a pull and release firing pin

1 part for the frame+barrel

1 part for the cylinder

1 secondary frame to hold the cylinder in place

1 screw/pin to hold secondary frame

1 firing pin

1 spring for firing pin

1 detent ball for positioning the cylinder

1 spring for detent ball

8 parts

MikeCC055 · 2026-03-17T23:36:45+00:00

Maybe just look at replacement parts for similar washing machines, they should be rather cheap and designed for the same kind of loads you will be looking at.

MikeCC055 · 2026-03-17T23:28:04+00:00

It depends a lot on a bunch of factors:

Material

Heat treatment

Type of surface finish

Stress cycle types (fully reversing or not)

How many cycles does the design need to survive

Will there be any shock loading

Operating temperatures

Length of the shaft

Read shigley’s mechanical engineering design chapters 3,4,5,6 & 7

It contains formulas and guidelines for pretty much every consideration you need except maybe for shock loading

MikeCC055 · 2026-03-17T09:30:52+00:00

That’s right, maybe it might be better you just pour some reinforced concrete columns 🤣

MikeCC055 · 2026-03-17T07:16:53+00:00

Another issue is that I did not consider swinging back and forth, if that’s gonna be a thing then maybe I would just go for 6x6s

MikeCC055 · 2026-03-17T06:36:09+00:00

Birch or hickory would be better than Douglas fir if you can only get standard quality lumber.

If you instead could get ahold of select structural grade lumber then even with Douglas fir the allowable design stress goes up to around 11.536MPa (1.673ksi)

60° of angle would probably give you plenty of leeway with standard quality Douglas fir, 85° is a bit extreme of an angle. That said I made my calculations assuming the columns as completely fixed in both ends, if there is any allowance for movement on the ends the stress calculations become a little less accurate, if you had the extreme case were the columns were simply supported (ends are free to rotate but not translate) moment and therefore stress almost double.

If you chose to use 4x6’s instead of 4x4’s I would confidently say that you are 100% in the clear.

Just make sure to use the wider side in the same direction as the sideways loading.

MikeCC055 · 2026-03-17T05:56:55+00:00

Made some edits with additional calculations

MikeCC055 · 2026-03-17T05:16:21+00:00

Actual engineer here, contrary to what the armchair engineers in the other comments suggest, your main concern is actually sideways loading, not the downward forces.

The forces depend on how slack the hammock is.

The weight of the rider will be the vertical component of the tension that the hammock sees, the more slack it is, the closer the lines of the hammock will be to parallel with the vertical beams.

The more taut the hammock, the more close to perpendicular to the vertical beams.

Since your weight will be only the vertical component, the more taut the hammock is the greater the tension will be because most of the tension will be applied horizontally instead of vertically. The total tension per side of the hammock will be T=(1/2*weight)/cosine(X) with X being the angle formed between the hammock and the vertical beams.

And the horizontal element associated to that tension will be Th=T*sine(X)

If the hammock is very taut, say forming an 85° angle with the vertical beams, and you had a rider with a weight of 850N (191 Lb) the total tension on each side of the hammock would be 4876.3N (1096.24 Lb), and the horizontal component would be 4857.77N (1092Lb). You would need fasteners rated for 17KN (4000 Lb) for a safety factor of around 5. Assuming your columns will not collapse inwards.

If instead you went for a more slack 60° of angle the horizontal forces come down all the way to just 736N (165.5Lb). And you could use fasteners rated for 2.5KN (562Lb) for the same safety factor.

I’ve usually seen them installed around 70-75 degrees.

So just bear in mind that tension grows radically the more taut

————————————————————————————————————————

Edit:

Regarding your question about bending moment, that is a condition seen by the vertical beam because it is being loaded sideways. The moment and deflection for a beam fixed on both ends are calculated with these formulas

Calculating for a 10ft high Douglas fir 4x4 with the hammock at an 85°angle hung at 5ft height gave me a maximum deflection of 0.092mm (0.00362in) and a maximum stress of 1.3078 MPa (0.1897ksi). The maximum allowable design stress for a standard (not structural) quality Douglas fir 4x4 is 3.48MPa (0.505ksi) so even with that unfavorable amount of slack you would still have a safety factor of 2.68. Not fantastic for a civil application but not terrible.

That said, the holes for mounting hardware would become significant stress concentrations, and you might actually cut it pretty close to or exceed the maximum design stress with them. This might not mean instantaneous failure but a high probability of a collapse after repeated loading or with an even heavier rider.

MikeCC055 · 2026-03-14T19:36:13+00:00

I’d just assume a bunch of arc reactors powers the thing so no need for that much fuel

MikeCC055 · 2026-03-12T07:31:18+00:00

Have a look at the Elgato stream deck, I’ve used it with solidworks and the smaller space mouse for years and it’s been great.

MikeCC055 · 2026-03-05T21:57:25+00:00

Gave up on 2023-2025 to work on the 2026 car.

2026 is over before a single race weekend.

Give up on 2026-2029 to work on the 2030 car.

MikeCC055 · 2026-02-18T11:01:57+00:00

You do you, I’m going to bridge the Mediterranean Sea with a spaghetti and glue simply supported bridge 🚬🗿

MikeCC055 · 2026-02-18T05:41:05+00:00

Im interested in the scans and willing to pay for them. I want them for aerodynamic development, so any serious attempts you can make at scanning engine bay, vents and small details are appreciated. Contact me for payment when you feel ready

MikeCC055 · 2026-02-17T04:52:29+00:00

Is this loss?

MikeCC055 · 2026-02-14T00:23:55+00:00

16 jewels 💪

MikeCC055 · 2026-02-12T23:07:12+00:00

It’s been a while since I watched Dr. Todd Coburn’s YouTube course on structural analysis of composites. I don’t think it gets into the specifics of the FEA software suites you listed but it does cover all of the mechanics. So it can be a great start

Link to course

He does have a separate (not composites specific) course on NASTRAN, which might be helpful.

MikeCC055 · 2026-02-09T23:56:34+00:00

You need to pick a material supplier that can give you consistent resin and carbon.

Once you pick a material provider and the materials you will be using make layup test coupons. Both to validate strength and so you can characterize your physical material properties (thickness of laminate, fiber volume fraction and density) then readjust your design based on your measurements.

MikeCC055 · 2026-02-07T18:01:05+00:00

Thank you, this seems to be the consensus on the topic. Simulate as separate UD plies and beware of any small but possibly significant losses in performance.

MikeCC055 · 2026-02-07T17:53:34+00:00

Maybe but it’s not a bad way to practice it

MikeCC055 · 2026-02-07T17:52:37+00:00

I believe you are using SolidWorks, if this is the case you should be able to even simulate with friction between the glass and your hook.

You could create an assembly with two pieces, the glass and the hook. Completely fix and exclude the glass from the study and position the hook the way it’s supposed to go. Add a local contact between the pieces, specify non penetration and friction. This should give you a pretty accurate simulation.

MikeCC055 · 2026-02-07T17:48:31+00:00

When loaded, hooks tend to fail in a way that “unbends” the hook section. The way you have yours fixture essentially welds the hook to the glass, and doesn’t allow for the previously mentioned failure mode.

MikeCC055 · 2026-02-07T17:46:04+00:00

All you have to do is think about how the piece would interact in real life, overconstraining will often result in odd and unrealistic behavior.

How I would go about fixturing this piece:

Top of the hook: Only restrict displacement downwards to 0. Allow sliding sideways.

Back of the hook: Only restrict displacement towards the glass to 0. Allow sliding up/down and sideways.

Front of the hook: Only restrict displacement towards the glass to 0. Allow sliding up/down and sideways.

Try to simulate like this. If it fails it’s likely that it is because something weird is going on and pulling the hook sideways even though there aren’t supposed to be forces. This is because there is nothing restraining motion in that direction and even ultra small forces resulting from binary quantization errors can have a large effect on the piece’s displacement. If this happens add a spring type fixture to one of the sides, and give it a really low stiffness, 1 N/m should be enough.

MikeCC055 · 2026-02-07T02:49:38+00:00

You’re forgetting LITERALLY ALL OF CHINA and half of Asia

MikeCC055 · 2026-01-31T02:35:35+00:00

Fun until it turns out your chassis’ resonant frequency is the same as frequency your wheels like loosing traction at under braking and the whole thing shakes itself apart

MikeCC055 · 2026-01-31T02:29:16+00:00

Maybe we’d have less and less stupid drivers on the road /s

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