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91
How do I?? / Make an Interval Timer for my Harbor Freight 220 Volt Spot Welder?
« Last post by vtsteam on June 13, 2025, 09:42:04 AM »
I'd like to make an interval timer for my Harbor Freight 220 volt spot welder.  I have a couple of timers coming in the mail. They use mechanical relays. Here's a pic:

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Specifications:
 Operating voltage: DC 6V - 30V, supporting micro USB 5V power supply
 Operating current: 50mA, static current: 20mA
 Working temperature: -20—60℃
 NO maximum load: < AC 250V/10A, < DC 30V/10A
 Size: 6.4*3.8*1.7cm

HOWEVER:

I'm guessing that triggering the inductive load of the 220V line of the spot welder might be too much for the relay, so I was going to add a second solid state relay, which would be triggered from the timer's relay. Maybe this one....

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Twidec/Output Single Phase SSR Solid State Relay
100A
3-32V DC to
24-480V AC
SSR-100DA

BUT, I was wondering if I could eliminate the middle man (the timer's mechanical relay) maybe desolder it and then just hard wire the relay coil's lines to the inputs of the 100 amp solid state relay?

Thanks
92
Member Videos / OKMO Microcosm M91 Model Hit & Miss Engine
« Last post by Jim Dobson on June 13, 2025, 12:29:36 AM »
Had a run of my OKMO Microcosm M91 Model Hit & Miss Engine

93
Yeah, scotch yoke seems to be easy one to animate/simulate properly, as the location of A (piston/conrod connection point in previous image), can be set to copy B's (yoke) location, by limiting its following behavior to consist only B's Z-axis movement.

To change gears - Although Blender's simulation/physics engine (Bullet) has some major issues with glitches, it can still be used for spotting/avoiding the same (tedious and probably takes too much effort to figure out what seemingly random errors are).

Nevertheless, there may be moments, when simulation runs as expected. An example, where vehicle drives around in circles, having its speed measured:

94
Tools / Re: What's inside of a Harbor Freight 220V Spot Welder?
« Last post by vtsteam on June 12, 2025, 03:05:35 PM »
The front arms. Upper moveable arm removed. Sits in cast aluminum retainer, attaches to brass contact shell:

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The handle pivot showing straight knurl for "press" fit (doesn't work well)

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Upper arm contact (brass right) lower arm contact (copper center) and pivot

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Upper and lower arm contacts (front view)

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Lower contact, showing insulation at bottom

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95
Tools / Re: What's inside of a Harbor Freight 220V Spot Welder?
« Last post by vtsteam on June 12, 2025, 02:51:46 PM »
End cap removed:

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The cap and back end of transformer windings

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The fixed handle and trigger wire running down channel to the switch:

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Switch with ring of paper insulator

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Switch wiring

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Switch construction

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Switch contacts

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96
Tools / What's inside of a Harbor Freight 220V Spot Welder?
« Last post by vtsteam on June 12, 2025, 02:31:21 PM »
What's inside a Harbor Freight 240 volt spot welder? Well the switch on mine was starting to act flakey, so I decided to find out.....

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End cap left, fixed handle lying on top of main body with switch wires and switch, moveable handle above that. Handle pin partly removed at front.
97
Project Logs / Re: Building Bernard Tekippe`s Regulator Clock
« Last post by smiffy on June 11, 2025, 04:06:35 AM »
Looking good a very interesting clock , it will be good to see how it performs . Mike
98
Project Logs / Re: Building Bernard Tekippe`s Regulator Clock
« Last post by raynerd on June 10, 2025, 04:01:49 PM »
I haven’t updated for a while but managed to get this running a bit better since the last video:

i=L3C9E2u0w4TBSGZw
99
The conrod is always vertical in a scotch yoke, but at a varying angle to the piston in a crankpin connection. Except at TDC and BDC. So the vertical distance is shorter in between.
100
That sure looks strange. So I thought that how about trying to replicate it in Blender, and the resulting curves look pretty similar.

Blue curves are motion paths, which were used to form curves on the top:

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