Hobart Beta-Mig II repaired, now I need to sort the drive rolls.

[forhire]

The other shop sent over an old Hobart Beta-Mig II for repair. I was told it didn't feed wire correctly. Upon inspection I found the main contactor was burned up. I suspected maybe it was working sporadically and due to weld/shop noise the user may not have noticed the contactor clapping. Someone had wired the input (480V single phase) using crimp on spade connectors. This created a lot of heat and eventually burned up L1 on the contactor. You. can't see the contact in the photo but it was completely smoked. I suspect the spade connector must have been arcing for quite a while. The lug was melted through. I thought about simply moving L1 to the un-used L2 contact, but L3 looked near death, so I ordered a new one. Thank you eBay! I checked the brushes on the feed drive motor, as I was certain they hadn't been serviced, but they looked good. Once the new contactor arrived and I installed it the machine appears to work properly.

But the solid wire on the machine didn't appear to match knurled roll. I would have expected a smooth v-roll. The tensionior was adjusted full tight, which immediately told me something was wrong. So tonight I poked through the manual Hobart sent me (Spec S-6967-1). I'm thinking I need a roll 375649-1 (0.035) or 375649-2 (0.045). I can't seem to find rolls online that match the numbers.

Can anyone school me on the Beta-Mig II drive rolls? Anyone have correct part numbers? Will I have to make my own?

I'm thinking this machine may have been setup for 0.052 or 0.0625, which would explain the need to clamp it down so hard to feed. I'll take the rolls and guide off tomorrow and see it I can divine what it's setup for.

[forhire]

Upon closer inspection I found the problem. The wire on the spool is 0.035 hard wire, the rolls are knurled two piece style, and the guides are 0.0625 (1/16). No wonder it didn't feed right.

I don't see any numbers on the rolls other than the size markings. The guide number is HOBART 377941 and is marked 1/16.

Looking at the manual it only lists input guide 377941 and 375655 for the output guide. So am I to assume the guides are 1/16th regardless of the wire? The manual does list two shims under the output guide without callout on the drawing, 376024 -.005 Mylar, and 407075-3 -.005 Steel. Not sure where the shims go or if they are needed. I'm thinking the shims center the rolls. If you look in the second photo you can see a very thin washer behind the plastic roll dog.

The output guide looks fairly worn. I suspect it's over sized.

[guajilloweld03]

https://www.ebay.com/itm/Thermal-Arc...wAAOSwyJVdMigW

These are the only drive rolls that you find on ebay.

Profax does have 376246-002 V knurled kit with guide,

377941- inlet guide and 375655 outlet guide
These are thermal arc for the Hefty suitcase.

[forhire]

These are the only drive rolls that you find on ebay.

Profax does have 376246-002 V knurled kit with guide,

377941- inlet guide and 375655 outlet guide
These are thermal arc for the Hefty suitcase.

Yeah, I looked at the 376246-006 rolls on ebay, they are a soft wire roll. This is kinda turning out to be a hard one to find parts for. The roll I have now are likely the 376246-002 V knurled or something very similar, as they are not marked with a part number. I'll look into the Thermal Arc guides. I may just send it back with a roll of dual shield on it and call it a day. I have the other shop digging around to see if they have any consumibles for this machine, it had been pushed into a corner for a few years.

[Brand X]

if you think this style will work, I have what you need.. Have some short guides, but not the long ones. I had the Thermal-arc stuff that was all Hobart, but paid little attention to the old school Hobart beta rolls,etc... Looks like the center hole is smaller on the betamig.. Maybe a
bushing to adapt to later stye? Depending on thickness on the old style stuff. Most of thermal ones run two rollers . top, and bottom pairs


https://www.ebay.com/itm/Thermal-Arc....c101195.m1851

[forhire]

if you think this style will work, I have what you need.. Have some short guides, but not the long ones. I had the Thermal-arc stuff that was all Hobart, but paid little attention to the old school Hobart beta rolls,etc... Looks like the center hole is smaller on the betamig.. Maybe a
bushing to adapt to later stye? Depending on thickness on the old style stuff. Most of thermal ones run two rollers . top, and bottom pairs

I'll need to measure the roll. I'm thinking it's 1.5" but I'll need to check it. This machine uses a single roll with a top bearing. It should be fairly trivial to make a new hub to accept a more common roll design, I think it's simple a matter of finding something that is the same diameter. We've been talking about using Miller rolls because they are readily available locally. I'll drag the machine back over in the morning and take another look.

I have a feed mechanism off a Millermatic 251... maybe it's time to Frankenstein it.

[Brand X]

I will post up some sizes /pics when I get a chance. I do remember the single driven bottom roll design.. I really have a pretty good set of drive rolls for the Hobart/Thermal stand alone feeders.I always liked the design and types available.

[Brand X]

Center holes is 1.00 outside dia is 1.6 inch and width is .565
has a smooth top flat roller @ .024/.045 A smooth groove solid wire bottom roller at .024/.035.

Two- .045 Knurled
Two-3/64 rollers
couple of guides

If they can work, then I will send them off. PM a address.

[forhire]

Center holes is 1.00 outside dia is 1.6 inch and width is .565
has a smooth top flat roller @ .024/.045 A smooth groove solid wire bottom roller at .024/.035.

Two- .045 Knurled
Two-3/64 rollers
couple of guides

If they can work, then I will send them off. PM a address.

My roll is 1.625". It's knurled, I'm looking for smooth rolls to run hard wire. The Miller rolls are about a 1/16" larger. I'm going to 3D print a new hub for some Miller rolls see how it fits up, I'm kinda curious to see how it goes.