Hammer blades for chipper.

[Mr J Morton]

Hello all
I have one of theses https://www.titan-pro.co.uk/p/372/15hp-chipper-shredder-mulcher, but quite old but still going strong.

The blades/hammer need changing as they have all bent meaning it clogs up, see photo

They want £25 for 4, there are 16 total. https://www.titan-pro.co.uk/p/3675/...oG50ZuFh18bkt3jNIyauWIIRYwo1ZxE4aAhwvEALw_wcB

I was wondering if you all think, like me, that they are mild steel? They seem to deform and not crack so don't appear to be heat treated.

I was thinking about either buying mild steel flat bar and making some up as they are not a complicated build or heating up the existing ones in the forge and flattening them out as they don't look too worn in length, but would this make them softer?

I don't want them flying around the garden passing through me on there way

What do you think? It's only for personal use and I'm trying to save some pennies

Cheers for any advice
Jon

 

[Erie Fred]

Why not unbend them for a first try ?

 

[Mr J Morton]

Heat em up first?

 

[Erie Fred]

Heat em up first?

That would help negate cracking, yes.

 

[Screwdriver]

Looks like they must have a squared off hole to mount on the shaft without spinning, possibly even a square shaft with round spacers (??)

Anyhow, they can't be mild steel or they would last seconds if only because the mounting hole would round off in a heartbeat.

My advice: sharpen them (if that is appropriate) and take note of the sparks. If, when grinding, the spark trails end like a firework, they are a carbon steel. Either way, you will want to get them red hot before straightening and then if you determine they are a carbon steel, harden and temper.

 

[bricol]

The link to the new ones suggest they are around 3-4 mm thick - I'd just give the old ones a squeeze in a vice to flatten 'em. From your picture, they just act as flails on a spinning disc assembly.

 

[Anguz]

is that the beast you fixed the pulley on a few years ago ?

 

[jo1010]

Theye should be high strength steel and heat treated....half the problem when I used similar machines in the past is the grill at the output end of the machine being too small to let material pass through.....so the material gets stuck inside the machine and then the hammers destroy themselves trying to beat it to a pulp. My workaround was to play around with different sizes of grill openings....still reduced the size of the material you feed in, but a quicker passage out....all depends what kind of result you want really...

 

[Agroshield]

Half the price you found here:

Pardon our interruption...

 

[Kram]

Looks like they must have a squared off hole to mount on the shaft without spinning, possibly even a square shaft with round spacers (??)

Anyhow, they can't be mild steel or they would last seconds if only because the mounting hole would round off in a heartbeat.

My advice: sharpen them (if that is appropriate) and take note of the sparks. If, when grinding, the spark trails end like a firework, they are a carbon steel. Either way, you will want to get them red hot before straightening and then if you determine they are a carbon steel, harden and temper.

If you clicked the link you would see they have round holes on a round shaft. They are free to spin on the shaft. The shaft does not rotate alone, the assembly of four shafts rotate, so each shaft is offset from the centre of rotation.

If it were me I'd likely use O1 gauge plate either unhardened or with a very good temper. It seems the flails are only intended for brush with branches upto 10mm diameter so shouldnt be under too much impact stress.

 

[Brad93]

when one lets go and comes through they side of the machine potentially taking you with it you'll wish you paid the £100

 

[Mr J Morton]

when one lets go and comes through they side of the machine potentially taking you with it you'll wish you paid the £100

Well that's what I was thinking, but I am very tight..

 

[Mr J Morton]

If you clicked the link you would see they have round holes on a round shaft. They are free to spin on the shaft. The shaft does not rotate alone, the assembly of four shafts rotate, so each shaft is offset from the centre of rotation.

If it were me I'd likely use O1 gauge plate either unhardened or with a very good temper. It seems the flails are only intended for brush with branches upto 10mm diameter so shouldnt be under too much impact stress.

You got it bang on. The only thing I would say is although they recommend 10mm in practice it takes alot more‍, hence the bent blades. But it's never needed new blades before, last time I replaced the spacers between the blades and it slowly gets a couple of bent hammers each season.

I make knives so I could temper them but the original ones had no temper I could detect with a file.

What do you think about heating straightening them? I used to have magnetic crack detecting powder, but can't find it .

 

[Migmac]

I think I might have some in my shed. It’ll be next week before I get a chance to look for them.

 

[Mr J Morton]

The link to the new ones suggest they are around 3-4 mm thick - I'd just give the old ones a squeeze in a vice to flatten 'em. From your picture, they just act as flails on a spinning disc assembly.

Yes that what I was thinking, I'm worried they are a harder carbon steel and may have micro cracks when I flatten them

 

[Screwdriver]

If you clicked the link you would see they have round holes on a round shaft. They are free to spin on the shaft. The shaft does not rotate alone, the assembly of four shafts rotate, so each shaft is offset from the centre of rotation.

If it were me I'd likely use O1 gauge plate either unhardened or with a very good temper. It seems the flails are only intended for brush with branches upto 10mm diameter so shouldnt be under too much impact stress.

Wow. Ok so the whole thing is spinning!!

That would have to go at a fair lick to eat branches then...

 

[Mr J Morton]

Half the price you found here:

Pardon our interruption...

That's alot more reasonable price!

Thanks for that.

 

[Mr J Morton]

Wow. Ok so the whole thing is spinning!!

That would have to go at a fair lick to eat branches then...

Oh yes it spins at a fair lick, it will take branches, cardboard and annoying neighbours!

If you add a long bramble or bush branch it whips it out of your hand quicker than you can react, it's gloriously dangerous.

Jon

 

[Screwdriver]

Yes that what I was thinking, I'm worried they are a harder carbon steel and may have micro cracks when I flatten them

Whatever you do, you should get them red hot before straightening. Give them a good look over for cracks because it's difficult to bend a hardened steel without it cracking. You might have to draw back the temper a fair bit too which is a bit tricky without knowing the grade of steel but certainly a blue (spring temper)
or beyond.

 

[Kram]

Oh yes it spins at a fair lick, it will take branches, cardboard and annoying neighbours!

If you add a long bramble or bush branch it whips it out of your hand quicker than you can react, it's gloriously dangerous.

Jon

All of these machines are. Bramble has a fair strength to it, enought that it was past used for making ropes.
You've seen the ropes in a chipper video? If not..