I killed my Hammer A3-31 because I’m a dumb dumb...

[Rod Sheridan]

Ok. Curious how getting jammed would have done the damage that's stated if the feed system could have slipped. What am I missing?

I don't think you're missing anything Jim, I had the same question.

I'm wondering if the sprocket was loose before the jam.............Regards, Rod.

[Rod Sheridan]

I am wondering if the sprocket was loose and the threaded portion worn before the jam.

If you have a piece that experiences a kickback it can be driven backwards with a lot of force.............Rod.

[Rod Sheridan]

Sorry to hear that Peter, however looking at the photo the depth of cut doesn't look excessive and the planer failed long after the wood contacted the cutterhead.

I'm wondering if the sprocket was loose for a period of time and wore the threaded portion of the shaft before the failure............Regards, Rod.

[Frederick Skelly]

Man, I'm sorry to hear about this Peter. I'm glad the damage was contained to the machine and that you were not hurt though.

Fred

[michael langman]

The specs for a3 31 say up to 4mm depth of cut.

[Peter Kelly]

You might also try getting a quote from a different repair tech, there's a few to choose from in Los Angeles. I understand this guy is familiar with Felder stuff: http://www.allmachineryrepair.com

I'm sure Felder uses a third-party service, could at least avoid their markup.

[michael langman]

The shaft to the sprocket that failed looks like it is not hardened. Having 2 flats over a short length, of non hardened steel driving a large round sprocket of that diameter does not look like something that would hold up if the end nut on the shaft came loose. As Rod has pointed out.
Was the nut loctited to the shaft?
The sprocket is only 1/4 to 3/8" thick at most. The shaft would easily self destruct if things came loose.
Is the rotation of the shaft opposite the rotation of the nut when tightening the nut?

[Thomas Crawford]

I'd try to repair it myself first without the weld replacing the components. I don't see how it would be impossible for an owner to do it. If it were me I'd have two things go through my mind: 1) I'm an engineer and I like the challenge and think I can do anything a tech can do in the end (which I'm sure is false in any number of cases but I like to try) and 2) The hammer is expensive - people that own it will generally have more money and are more willing to pay for repair. Or they are a small production shop and can't afford the downtime to DIY repair. That could explain why the tech has never seen anyone fix it themselves.

[Darcy Warner]

Sorry, I still think the quote from Hammer to repair it was a good price. More to it then just knocking that shaft out and replacing it, but everyone is an armchair engineer.

My favorite part of fixing something after someone tried to fix something is that it always pays better.

[Gustav Gabor]

It's kind of hard to see from the pictures, but is there enough of the flat areas on the shaft remaining to still engage in the rectangular (slightly deformed) sprocket hole?
If so, I'd grind the end of the shaft flat and drill and tap the shaft and use a bolt and washer to fasten the sprocket. (assuming it isn't a hardened shaft!)

If the shaft and sprocket are deformed to the point that the sprocket spins or has very little bite, I'd get a welder to build up the shaft and the deformed part of the sprocket and then grind and file to mate the parts perfectly.
Probably wouldn't need a large bolt (maybe 5/16" or even smaller?), as the pressure is on the flats of the shaft and the sprocket, not the bolt.

If it were my machine, this is what I'd try first. Relatively easy, cheap, and the shaft can still be removed. Welding the sprocket onto the shaft may be quicker and would be very strong, but without knowing the machine, it might make it difficult if not impossible to remove the shaft once welded.

[michael langman]

Sorry, I still think the quote from Hammer to repair it was a good price. More to it then just knocking that shaft out and replacing it, but everyone is an armchair engineer.

My favorite part of fixing something after someone tried to fix something is that it always pays better.

This is sound advice.
When I was in machinery repairman class A school in the Navy we were required to repair a damaged pump shaft. This meant cutting off the damaged part of the shaft, drilling and boring the end of the shaft to accept the new piece that was a machined press fit onto the original shaft, and then remachining the shaft between centers with a center rest to keep things concentric within .001 of an inch, after the shaft was welded.
But those pump shafts were much more expensive then the shaft on the A3-31.And repairs were done in emergency situations. That shaft on the A3 31 is an inexpensive item from the manufacturer.
Disassembly is required to fix it properly.
If it were my machine, I would ask the manufacturer if there was a weak link that would prevent this type of damage from happening built into the machine. Such as a shear pin between the cutter head and the arbor. After all this machine looks like a glorified snowblower to me, in it's drive mechanism.
If not then I would be inspecting the machine on a periodical basis to prevent this from happening again. And loctiting all of the hold down nuts on the shafts.
If I had a kick back as Rod described, then I would also shut down the machine and do an inspection.
There are alot of these machines out there, so I hope the overall posts, on this topic may prevent this from happening to someone else.

[Ben Rivel]

Scary! Glad I read through this and am aware of it now! Just one more thing to be paranoid about in the shop! lol

[Peter Lashley]

Thank so very much for all the input and suggestions, very appreciated.

I did get confirmation from another Felder / Hammer Tech that it is a 4-6 hour job. Don’t know yet if I can replace the roller and parts myself and perhaps just have a tech calibrate the machine if I can’t get it right or if that’s risking making a tech repair job all the harder. Just noticed there are some heavy duty looking castle nuts holding the cutter head in place and my only wrench for those nuts is way too small, so need to figure that into my plan but who doesn’t look for any excuse to by more tools...

I will call the repair guy suggested by Peter Kelly, just to get a different perspective and as he’s in LA, so might be a bit cheaper.

in response to some of the questions, and I’m sure I’m missing some, the nut was sheared off and still has the threaded rod bit inside it. I tried seating the gear onto what’s left of the feed roller rod and there’s not enough of the flats for the gear to bite onto, it just spins freely. As a side, while going thru the machine again I found the drive chain, which usually spans the two roller gears running directly over the cutter spindle, had dropped onto the cutter drive rod, when the gear failed, and the friction of it spinning forced the chain in to an arch, (small bridge) and fused it in this shape, grinding the underside of the arch smooth. So have to add a drive chain to the parts list. This may have been the smoke smell but not sure.

Some inquired about the A3-31 depth of cut protection and indeed it does have it. There’s a row a pawls and a the bracket that holds them when combined, act as depth protection and kickback preventers. I think what got me was the taper of the piece I was working. It was thin enough to initially get under these pawls and the bracket but as the thickness rapidly increased it eventually forced the in feed roller to stop, causing the back lash.

Just for perspective on the Hammer itself, it has been a phenomenal machine, at least to my non-professional eyes. I agonized about spending so much cash on a machine but at the end of the day when I looked at two comparable capacity Grizzly, Jet, etc., machines and the size they’d take up in my garage, I decided to save up and get the Hammer when it went on sale several years ago. It really has worked great and I’ve really enjoyed working with it. This current debacle is completely my fault as I was tired and lost focus, planning to square up the three sides and rip the taper off at the table saw. But, I feed the tapered side in and this was the result. Very expensive lesson but as several have said, very grateful I wasn’t hurt.

Still working out what direction to take moving forward. I’ll make a few more calls, including the guy mentioned earlier, as he does repairs and welding so it might be the perfect guy to get perspective on both options, repair or weld.

Again, I really appreciate all the suggestions, advice and reminders to learn from my mistakes.

[mreza Salav]

Dont blame it on yourself. I still think the machine should have not behaved the way it did. Simply trying to plane a tapered piece shouldnt be self destructing to the machine.

[Rod Sheridan]

I still don't see any evidence of damage to the workpiece, or excessive depth of cut.

The burning smell could have been the friction roller that drives the planer feed. Inspect it carefully for flat spots or damage.......Regards, Rod.