Thread: Mulcher Flail Spacers

I'm replacing the flails in my chipper/mulcher. I've ordered new flails online but I can't get the spacers, so I'll need to make them. The original spacers are made from very soft seam-welded steel tube. As you can see, they mushroom badly, which is hardly surprising given the flogging they get and the material they are made from. They are 5/8 OD x ½ ID. I'd like to make the new ones more robust because when they mushroom they make removing the flail pins very difficult. I'm thinking of drilling and reaming ½" holes in parted-off lengths of 20mm round steel bar. Ideally I'd like to harden them too, so something heat-treatable would be good. They won't need to be tool steel hard, just harder than the rubbish the originals are made from.

Anyone know what a suitable grade of steel might be?
And where to get it in Melbourne? I'll need about 300mm.

TIA.

For something more robust, 4140 is usually the go. Can be used as is or hardened up.

Michael

In Melbourne I buy my 4140 pre hard from interlloy in Dandenong. Or sometimes from Highett scrap metal

Thanks gents. I'm heading to Dandenong tomorrow.

Would it be possible to harden the 4140 by heating to cherry red in a wood heater and quenching in water?

Originally Posted by jack620

Thanks gents. I'm heading to Dandenong tomorrow.

Chris, if you ring bohler in dandy in the morning and tell them you want to buy some offcuts they will book a time with you, if you buy offcuts there is no cutting fee and I am pretty sure it will be a good opportunity to stock up with odd's and ends.
I tend to go a bit sick when I go in there, had a car dragging its mudflaps on the road once when i left there

cheers, shed

Would an automotive anti-roll bar be worth considering for stock? I'm not sure exactly what type of steel they (definitely a type of spring steel) but know they can be hardened reasonably at home as
I made a chipping hammer from one many years ago. From memory I just heated it up cherry red, quenched in oil then tempered back to blue. Its held up well over the last 30 years.
Guessing you'd probably need to anneal it before you could drill it.
Probably more hassle than its worth if you've got access to reasonably priced virgin material, but just a thought...

Steve

Hi Steve,

If I wanted some bar/rod that is exactly what I do, grab it from the local scrapyard. Knowing what the steel was originally intended for is an advantage, because sometimes the metal is really strange ! I have picked up various pieces that have produced a very funny odour when I've machined it.
Apparently it has been leaded steel ! It machines nicely, but what a pong.

Hi John (shed),
Thanks for the tip. I will call Bohler and see if offcuts are available.

Steve and John (baron),
I prefer to stick with material of known pedigree as my machine doesn't have a lot of grunt to be drilling a ½" hole in really hard material.

I got a couple of offcuts of 24mm solid 4140 H+T from Ian Stansfield-Smith Metals in Hallam for $10.

For future reference:
Bohler are now called Voestalpine and have a min charge of $105+GST for non-account customers. This includes for offcuts.
Interlloy are now called Vulcan Steels and have a min charge of $250+GST.

Thanks to all for the feedback.