Loose shredder

i wonder if someone had a similar problem. I have finished assembling the shredder, but because the steel it was cut from had tolerances up to 0.15mm i ended up with a gap between the blades (about a milimeter in total, not between each blade) and a bit smaller gap with the part in which the blades sink (not sure what the correct name for that is). It rotates, but i wonder if i should just connect it to the motor to see what happens, or if i shall look for another solution (reordering parts come to mind, but it takes 3 weeks + expense, so if some DIY solution is found – that would be great). My take is that it will not work and jam when it is under load.  I would appreciate any help. Thanks

have you got pictures to help me figure out what is your problem ? i have assembled more than 40 so i might be able to help you, or at least to try

@alexpolyenov, how is it going ?

We received quite some off parts from the bazar and no we have pretty much the same problem but I’ve figured some ways to get this going :

1. weld as the mobile blades best possible on the hexbar (2 clamps or lathe tail stock setups) – silly but always worked

2. rotate the shredder box in way that the stationary blades are on the bottom, drawn down by gravity

3. now slide in each stationary blade one by one, if you need space : use a sheet gauge/spacer, number it so you can find it back. grind everything out of the way just 🙂

4. after you’ve got them all in, dis-assemble the box again and weld the spacers on the stationary – silly but works well – til the point you have NO friction anywhere 🙂

I am updating the wiki – so NO one else walks into this anymore, ever ever again.

thanks PPBOYS,
i get the picture. It should either be really tight and not rubbing any parts or it is best not to put it under load at all. As i have mentioned earlier i am now giving up on the idea to test it at full power (only 2 days left for that) so now i should have more options for fixing it, as i might go back to the laser cutter with this xls sheet and see if they think that is acceptable to give me 4.8 metal when i have paid for 5mm. It might be more reliable to reorder some of  them (at least 5mm spacers, which seem to be the biggest culprits.
I’ll grind the blades tomorrow as per your advice, i thought the ends might be a bit too sharp.

thanks for the idea, i have now done that, i’m attaching the file just in case someone wants to have a look what a mess it is. I’ll see if there are any better ways to combine them now. It seems that i’m running out of time, as i was trying to test the shredder here where i currently live but am moving out in 2 days. The motor i have is 2.2kw (70rpms) three phase. I have three phase connection here, but not have one where the shredder is moving, so now won’t be able to test with full recommended 2.2kw as it will output maximum 2/3rds if setup to work with 220v.

oh dear,
yup, you want :
– do as @s2019 said, use sheet gauges and weld them on – which can be difficult or tedious with out a TIG welder
– grind your hex washers
– grind your blade tips (they come out always too sharp)

and then it’s a miracle that you don’t up scratching the side plates. consider this thing extreme violent, tie up all with anti-loose washers. the stationary spacers btw. can be lifted a little upwards but you have to weld them with a bar into place which could break too.

good luck,

Hopefully one of the builders gives you a detail process. In the meantime I would make a spreadsheet of what you have with measured thickness and gaps by location to help form a shimming strategy, or re juggling of your spacer blocks.

Hi! Thank you! I was away from the shredder yesterday, just got a chance to film it/ I have recorded a short video, i think it might illustrate the problem better than the picture: https://youtu.be/QPmm1bq-EgI
As you can also see blades are all over the place, not centered inside each hole, but either a bit to the right or to the left. I’m not sure if that is a big deal?