Jigsaw blades to cut welds and plate?

[Lca078]

I need to cut off a welded track sprocket ring on a track loader (same undercarriage as a small Cat D4 Dozer from the 70's) and then weld on a new sprocket in the field. See the pics for a pic I found on the net to explain what it looks like. This isn't mine but it gives the idea.

I don't have easy access to an oxy-acetylene torch or plasma cutter that I can drag out to the field so I'm wondering if I can use a jigsaw with good blades to cleanly cut off the sprocket. I'd be cutting through old welds (no idea on the hardness) and trying to follow a gentle curve so I have a clean way to weld on the new ring. I'm pretty sure I can get into that space easily with my variable speed Bosch jigsaw (the good model where you have to use the long skinny screwdriver from the top to change blades) but have no idea what decent blades are available nowadays. I prefer not to use a grinder or other tool that can't follow the curves. If I can't use the jigsaw, I'll probably pay for a welder to come out and do it with a truck rigged for it. Am I missing any good ideas?

Welded thickness is between 3/8" to 1/2" depending on the weld-daubering. Each cut would be about 5" long x 9 per sprocket with 2 sprockets on the loader. That's 90" of cutting!

What are ya'll thoughts on this?

 

[Big B]

4 1/2 inch angle grinder with an abrasive wheel. Probably take less than an hour each. You'll need a shower and clean clothes when you're finished. If you have a cordless grinder with plenty of batteries that's a bonus. The round wheel can easily follow the curves.

 

[Nmbmxer]

I'd find another way that sawing all that off, that sounds miserable. I'd find / rent / buy a oxy fuel torch, plasma, or air arc kit first. Air arc is really fast, just loud and messy. With a little practice you can pretty precisely gouge out metal.

Though if you cut straight across each spoke to sprocket joint with a grinder the amount you'd have to clean up to make it round might not be that much depending on the diameter and I'm sure it would faster than a jig saw.

 

[Bill D]

Even Hoe depot sells carbide tipped reciprocating saw blades. I would guess that they have them in jigsaw shank as well.
Bill D

On edit:

DIABLO 3-1/4 in. Carbide Teeth Thick Metal Cutting Jigsaw Blade DJT118EHM

DIABLO's carbide jig saw blades deliver extreme durability and superior cutting life in thick metals ranging in thickness from 1/8 in. to 1/4 in. High-performance carbide strip provides an unmatched up

www.homedepot.com

 

[DDoug]

Lance.

Ask here:

Dozers

www.heavyequipmentforums.com

 

[rklopp]

I have one of those old-school Bosch saws. No way would I want to try cutting that thickness of steel with it unless I was billing my worst enemy by the hour plus consumables including the saw itself. The saw will handle 1/4” aluminum plate, but it is no fun operating it.

 

[henrya]

If there is any way possible, take it off the machine and to a shop.

 

[Metalurgent]

Assuming you're not trying to save the old ring...maybe a Portaband with a bunch of blades and a helper with a spray bottle of cutting fluid..
Depends on the clearance if you can swing the bandsaw around..

 

[Lca078]

All good input so far. I'm struggling to see how a cut-off wheel or small grinder will be any cleaner or easier than the jigsaw because of the radius. If it was a straight line, I'd be all over the cut-off wheel.

I'm already a member on the Heavy Equipment Forums. Here's the thread where I snagged my first pic: https://www.heavyequipmentforums.com/threads/cat-941b-resurrection-under-carriage.89206/ Post #23 Excellent knowledge there on how to repair these old beasts but I only come here for machining advice. Everyone there just uses the blue-wrench to remove the old rings and some metal glue to hold on a new one. Bill D- The carbide recip blades are a good idea- I didn't know those existed now. But I agree with rklopp I'm probably risking tearing up my dad's Bosch he handed to me 15 years ago. If he found out I hurt that Bosch, he'd probably be madder than when I was a kid and he found out I was 'grinding' aluminum on his bench grinder that he saved for sharpening his HSS bits. I learned the hard way what it meant to dress a wheel....

I didn't think about the Portaband. That's an interesting idea. And no, not trying to save those old rings. Hmmm... would be a good excuse to finally buy one of those!

henrya- The only way to remove the sprocket without using a 100-ton field press is by removing the whole final drive assembly. If you look through the holes in the sprocket in my first pic, you can see the bolts that hold the final drive to the body. Doable but way more trouble than getting a second hand oxy-acetylene system. But you got me thinking. If could mount a small tool-holder with a cut-off HSS bit solid against the frame, I could feed the HSS bit into the wheel while the dozer is idling in 1st gear, acting like a lathe. I just don't have a tool holder...

 

[Big B]

Are they welded on the inside too or just the outside?

 

[dian]

definitely forget the jig saw. even the $10 diablo blade* will not cut through 1/2" of that steel, you will not be able to create enough pressure for the teeth to bite, and if you do somehow you will breake the saw. and 90" of it? no way. imo a portaband (are there carbide blade for it?) will die on you as well, the ones iv seen were all toys.

* this is the first time iv noticed they are supposedly made in my country. a sales gimmic imo, you cant even buy "diablo" around here, internet only.

edit: i would consider rigging up a 150 mm angle grinder stand somehow. it will be a bit of work, but that work will not make tears roll down your cheeks and maybe you can use it in the future too.

 

[Lca078]

Yes, welded both sides. Good mud-daubering job too! yeah, I have a feeling I was dreaming about using a jigsaw. The more I think about using a jigsaw to cut 1/2" steel (welds at that!) for 90", the more I realize i'm just asking for trouble. I'm imagining sitting on a 8'x4' sheet of 1/2" plate that's harder than mild steel and trying to use a jigsaw to cut a strip off the side. That ain't happening!

 

[DDoug]

Jack it up, start engine, put in low gear.
Rig tool post grinder (or the handy 4 1/2" angle grinder)
On simple HF "Cross slide vice" and grind away.

 

[michiganbuck]

QT Op( But you got me thinking. If could mount a small tool-holder with a cut-off HSS bit solid against the frame, I could feed the HSS bit into the wheel while the dozer is idling in 1st gear, acting like a lathe. I just don't have a tool holder...

Likely the fuel use turning with a tool bit would cost more than cut off off abrasive wheels.

Yes likely need to buy the bargain brands. Might get 5 inches per wheel about $.20 an inch.

20 VCT Pro 7" Cut Off Wheels Disc Blades Hard Metal Fits Dewalt Grinders | eBay

Fits all Dewalt Grinders with 7/8" Arbor. 7" x 1/6" x 7/8" Cut off Wheel. Hub shape. Industrial quality, double reinforced.

www.ebay.com

 

[DDoug]

QT Op( But you got me thinking. If could mount a small tool-holder with a cut-off HSS bit solid against the frame, I could feed the HSS bit into the wheel while the dozer is idling in 1st gear, acting like a lathe. I just don't have a tool holder...

Likely the fuel use turning with a tool bit would cost more than cut off off abrasive wheels.

Yes likely need to buy the bargain brands. Might get 5 inches per wheel about $.20 an inch.

20 VCT Pro 7" Cut Off Wheels Disc Blades Hard Metal Fits Dewalt Grinders | eBay

Fits all Dewalt Grinders with 7/8" Arbor. 7" x 1/6" x 7/8" Cut off Wheel. Hub shape. Industrial quality, double reinforced.

www.ebay.com

Idling that engine will not cost that much.
Grinding off the teef to make an accurate, concentric fit for the new sprocket
will go a long way.

 

[dcash]

In my neck of the woods there are rental places that have Oxy/Acet cutting setups for $50-60 per day (+ gas). Can't imagine this is much more expensive than all the saw blades you'll need, plus your time.
A sawzall will probably work better than a jigsaw. I've used them for cutting fairly heavy plate when I couldn't use a torch, but you'll still eat blades, and it's nowhere near as fast as the torch.
Also, since you're gonna need a welder to glue the new one back on, have you considered "scarfing rods" to gouge the old welds out?

Dave