Slipping amp adjustment shunt.

admin

I have Century buzz box like these https://www.google.com/search?q=cent...w=1366&bih=667.Every time I set the amps above ~130 as soon as I start welding it slips back down to 110 115ish. I am thinking its just vibrating enough to drop the shunt back down. Any adjustments I can make to correct this?
Reply:I'm assuming you have the squeeze handle style?If yes, take it apart and fix it - your rivets holding the handle together are likely wallowing out their holes and getting sloppy.Or just hook a bungee cord to it so the extra pressure keeps it from sliding.The parts to replace the bad ones are pretty generic and can usually be found - but much cheaper to fix yourself.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Yes squeeze handle style. The handle it self is feels solid. I can't move it with out squeezing it, its just while welding that it slips. I wish I would have checked closer while I had it apart to clean it out.
Reply:Jesus, you have a welder! Put the handle where you want it, and tack it there. Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Century buzz-boxes have an adjusting mechanism that sets the pressure on the shunt when it is locked. It is basically a lock nut on a stud attached to the transformer core.You need to remove the case, then tighten the nut one quarter-turn at a time until the shunt stays put. Do not over-tighten or the amp adjusting lever will be very hard to move.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:I discovered that I had this same problem with my Century Buzzbox 230.My solution was to open the case and run a length of steel plumbers tape around the lever between the shunts. I used a small machine screw and nut to hold the loop tight to the lever and ran the tape up through a notch I cut in the top of the case. Now I can set the current and shove a nail through a hole in the plumbers tape to keep the shunts from slipping down. It is a little ugly but it works great.
Reply:You can probably accomplish the same trick with one of those useless welders magnets. Simply adjust the shunt, then stick the magnet under the handle to the metal case so the handle can't slip down..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:One of my customers has a Century, which I wrap a bungee cord on the handle to prevent slippage.I like DSW's magnet idea though!Its not mine so I won't take it apart, He is too lazy to fix it, else he would be doing his own Welding, not paying me to do it.
Reply:If you can find a strong enough magnet that might work. My first attempt to keep the handle in place was to wedge a 2x6 under it but it just got kicked out so I came up with the plumbers tape fix. There is apparently quite a strong pull on those shunts in certain positions.
Reply:I would investigate the problem internally to see if there was an easy adjustment or quick for the original design, but seems like that mechanism always ends up causing issues.That said, if it was going to take a lot of work or require the purchase of expensive parts then I would simply take a scissors type floor jack from a salvaged auto junkyard and make my own adjuster machnisim using the scissors jack to the original handle.  A carefully placed bracket to the front of the welder and a pivoting linking to the handle and you would be in business for cheap.  The new scissors jack would even be infinitely adjustable with more precise control than the original move the handle by hand way too.
Reply:Mine started this today.  Came to do research before i turned the only screw inside the box.  If that doesn't work. I'll fix up a vertical threaded positioner with a wheel/crank (plus a pointer) and make that thing adjust PROPERLY.   Silly squeeze handle!
Reply:Like the Miller ThunderBolt, put a vertical screw out the Top.....
Reply:Originally Posted by drujininLike the Miller ThunderBolt, put a vertical screw out the Top.....