View Full Version : dumbell

01-17-2014, 01:21 AM
Could be dumbass- but we'll see. I picked up an 8 lb dumbell the other day. It is cast as one piece, handle and two ends. The handle is basically round, so I'm going to cut it in half and chuck it. It will either machine ok, or it will be a nightmare of hard inclusions and cutter-breakers. If all goes well the pieces could become screw-on backplates for my lathe.

01-17-2014, 01:47 AM
I do know with the plastic coated ones, whats inside might not be metal.

The Artful Bodger
01-17-2014, 02:14 AM
Your cutting tools will love you if you go over it with an angle grinder first taking off any crusty stuff and especially raised lettering.

01-17-2014, 04:41 AM
I wouldn't have brought this home if I was unsure of the composition. I've been bit by the plastic covered 'mystery weight' thing before- thinking that it was cast when it actually turned out to be concrete or something.

I was concerned about this being a poor material full of pits and sand or whatever, but just from the look of the material inside (I cut it in half to look at the metal) it seems clean and decent. Of course, turning it will tell the tale.

01-17-2014, 07:57 AM
Just took a load of scrap to the recycler (big old scrapyard older than I am) they wouldn't accept cast window weights - said too much lead. Anybody know anything?

01-17-2014, 08:55 AM
I threw out a weight set once because no one wanted it. Should have saw the garbage guy trying to dump that garbage can into the truck!

01-17-2014, 09:04 AM
Lol!! Now that is funny Andy, been involved in a couple of those shenanigans too! Lol

01-17-2014, 11:25 AM
I used a 10 lb cast weight for everyone of my backplates. For the. 8inch and the 6
Inch, 3 and the4 jaws. They have been working for years and thousands of parts without any issues
Use a carbide cutter and turn as slow as possible. Cast is VERY dirty . The new
Weights are cast with spokes and won't work for this purpose.

The Artful Bodger
01-17-2014, 02:11 PM
Yes, very dirty to turn but the metal in the 3 or 4 weights I have repurposed has always looked clean and uniform once the skin was off.

Alistair Hosie
01-17-2014, 04:06 PM
I was warned to expect absolute dirty casting material with all sorts of crud inside. When I turned the two I did , they turned out to be really nice throughout. I kept all the small ones my son doesn't want or need them so if I need any more I have stock, so maybe I was just lucky .Mine did not have a plastic coating just paint,The plastic ones as far as I know come empty and you fill them with cement or sand.My experience was very positive that's all I can say have fun safely Alistair

01-17-2014, 06:42 PM
Cast weights can be very dirty apparently I,m sorry I don,t know enough about it all. There was a story around a few years back when a sparky went to attach a flashing light to the counter weight of a forklift basically the the drill bit melted and the drill it self sort of exploded. The reason being it wasn't cast iron but a derivative of Q-metal that has depleted Uranium in it just being doing a search to find the article with no luck maybe some one knows more
Cheers Kiwi

01-17-2014, 06:44 PM
I always thought the inside of a dumbbell was Plutonium...you know, like a bowling ball.

01-17-2014, 07:03 PM
I sent fifty window weights to the scrapyard last year, they took them and I got paid. They did test them before dumping them, They turned out to be high grade cast iron.

J. R. Williams
01-17-2014, 07:50 PM
Cast iron window weights can be easy to machine and I have made piston rings from one but most have extremely hard places that merely rub off carbide tools

01-17-2014, 08:08 PM
I tried to drill through a dumbell once, as I was planning to use it for a slide-handle-hammer.
My drill bits wouldn't even bite into that 'mysterium'.
I scrapped the idea, and just turned a piece of 1018 instead.

01-17-2014, 08:13 PM
I have had the misfortune to try machining sash weights- I ran into hard spots and that was that. I've generally been lucky- one of the few where I wasn't was trying to bandsaw a piece of mainline rail. I got largely into it ok, but suddenly progress stopped. Another thing I don't muck with anymore is bed rail. Or that piece of work-hardened aluminum bronze-

01-17-2014, 09:55 PM
Huh. I took 700 pounds of window weights in last year and they didn't even blink and eye. Just pointed me to the cast iron pile.

01-18-2014, 12:09 AM
Huh. I took 700 pounds of window weights in last year and they didn't even blink and eye. Just pointed me to the cast iron pile.
The scrapyard has one of those hand held analyzers, they separate the "good cast iron" from the junky stuff. so they will shoot one or two items to test. I am looking to buy 220# of lead off of them here soon for counterweights for the press. They will sell to the public, last I checked they had 175lbs of lead there. it is mostly wheel weights and battery terminal clamps so it will all have to be melted(5lbs at a time), cleaned and then poured into the counter weight tubes.

01-18-2014, 12:52 AM
A lot of weights are made on automated casting lines, to speed up the process they cast onto water cooled moulding beds with spray water quench that leaves the casting as hard as cementite can get, very,very hard. Best thing to do with them is burn them in a small garden fire, ie chuck them in and leave them till the fire goes out and cools, the slow cooling allows the things to recrystallise, theres still a bit of skin but greatly reduced and the whole experience will be easier on your tools.
Its quite alright to spray water onto molten iron or steel but you don't want molten steel or iron landing on water! Not big quantities anyway, it goes boom as casting both have taught me, burns to prove it!

Don Young
01-18-2014, 10:35 PM
Brake wheel and master cylinders yield some really good fine grained cast iron. It should make good piston rings. Some crankshafts are made of good machinable cast iron and the throws can be good sized chunks. I have a chuck back plate made from a motorcycle crankshaft.