Beginner needs simple help!

So the company i work for uses specialized shredders to make gift basket shred. I dissemble and put back together the shredders for maintenance. Were at the point where we need new plates that hold the bearings/gears and cutters. Ill post some photos. It uses 2 larger bearings that arent really suppose to be a press fit (incase shredder jams it wont snap anything) and after months of use the bearing holes widen due to the bearing bouncing around. Should they be press fit ? So how do i find the true center of the hole since they have became misshapened ? . We have simple tools here at work and best thing being a drill press. What drill bits ? Basically i have a blank block of aluminum and need to copy whats in the pic. All the holes as well.

You may need to circle back and edit your post to include the pic.

If OEM parts are available, it's likely that's your most economical repair, especially if all you need is the part, and not a service call.

If they fail after 'months' of use, then they're not really designed for what you're doing with them. Not the end of the world, but you may need to look for better bearings/pillow blocks/whatever to modify them for longer life.

Without the pic it's hard to guide your search. But check out McMaster Carr on the off chance they've got something that will work...

Jay96 said:

So the company i work for uses specialized shredders to make gift basket shred. I dissemble and put back together the shredders for maintenance. Were at the point where we need new plates that hold the bearings/gears and cutters. Ill post some photos. It uses 2 larger bearings that arent really suppose to be a press fit (incase shredder jams it wont snap anything) and after months of use the bearing holes widen due to the bearing bouncing around. Should they be press fit ? So how do i find the true center of the hole since they have became misshapened ? . We have simple tools here at work and best thing being a drill press. What drill bits ? Basically i have a blank block of aluminum and need to copy whats in the pic. All the holes as well.

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Well then this conversation will revolve only around changing out parts then.

If management won't provide you with the proper tools for the job.

Sorry let me explain myself alittle better. Im in mobile and its not letting me post pics so tonight on my laptop i will . My company designed these shredders for our own use. Patented of course so theres no OEM parts. These were designed and built by my bosses husband before he passed so all new parts must be made inhouse at the time of repairs. Basically this 1inch aluminium plate holds 2 bearings . The bearings are ITC 5206-2rsnr . Should these be press fit? Ive seen people freeze the bearings so they drop right into their holes and eventually expand due to temperature. The plates we have now that hold the bearings for some reason, the holes enlarged from the bearing bouncing around when the shredder jams with paper.

It sounds like the aluminum is to soft for this aplication and is deforming under hammering loads by the machine. Make new bearing plates from harder aluminum or better yet steel, a light press fit would probably help also. Hard to really say without pics. You will probably need a milling machine to remake the parts.
Where in Calif are you?

Yes a picture would be very helpful. However without knowing anything about the design, I don't think a bearing clanking around in a hole is a great idea. You said that the design was supposed to offer some protection from jamming. Could you mount a pillow block on a heavy piece of angle iron outboard of where the bearing is now? If you could allow the angle iron to pivot on a bolt with a very heavy spring pulling against the shredder, then it would have some give to it. That will not work however unless you have some extra shaft hanging out. Of course I have no idea of how this thing is put together but there are all kinds of bearing hangers that would bolt to that AL plate and stiffen things up if you don't want the bearing to flop around.

Keep in mind, too, that the design could be such that failure first occurs in the easiest-to-replace part. If you make the bearing surround much stronger, will that cause things like the blades themselves to fail? Or their support? Look at the whole situation before you re-design/substitute.

Very close tolerances and steel construction likely would be worth its cost, a good design and sending the the making of the device to a machine shop would be a good choice.

Even with having the right machines it seems your shop might not how to make such a device even with the sample/original for looking at..

Shreds are an interesting product.
Amazon.com: gift basket shred

michiganbuck said:

Very close tolerances and steel construction likely would be worth its cost, a good design and sending the the making of the device to a machine shop would be a good choice.

Even with having the right machines it seems your shop might not how to make such a device even with the sample/original for looking at..

Shreds are an interesting product.
Amazon.com: gift basket shred

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I'm with you on this one. Op needs to send it out. An accurate 62 mm hole in a drill press isn't going to happen. Maybe with a boring head if the vibration doesn't cause the morse taper to fall out. Long shot would be special drill and custom reamer.

digger doug said:

Well then this conversation will revolve only around changing out parts then.

If management won't provide you with the proper tools for the job.

Click to expand...

I'm pretty sure they make drill presses with mill tables....oh yeah, bridgeports

Hardplates said:

I'm pretty sure they make drill presses with mill tables....oh yeah, bridgeports

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Yup, a HF benchtop drill press, with a HF cross sliding vice.
Chuck up endmills in the Jacobs chuck too (heck use HF wood router bits)….

Doo recall the OP indicated (as I highlighted in red) they only have a DP.

Not a Bridgeport.

digger doug said:

Yup, a HF benchtop drill press, with a HF cross sliding vice.
Chuck up endmills in the Jacobs chuck too (heck use HF wood router bits)….

Doo recall the OP indicated (as I highlighted in red) they only have a DP.

Not a Bridgeport.

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Tomato, Toemato, lets not get caught up in the details here It sounds like a lot of work and revisions need to go into the design long before getting a machine let alone figuring out how to use it.

All the support in the world won't come close to hiring someone who knows what they are doing. It's likely a simple job that a couple steel bushings could be pressed into the old holes after boring them out. Putting them back on location.....figuring out where location is could be an entire project in itself. Without pics its a shot in the dark.

It seems to me that you have at least three questions here. The fit of the bearings and how to layout the new part and how to make the new part.

The fit of the bearings: A bearing supply place should be able to tell you how a given bearing should fit. Some BBs will jam if used in a press fit while others are made for it. Talk to your supplier. Find a local one if necessary or work with a more distant one on the phone.

Layout of the new part: The overall outline should be easy, just measure the existing part. With no photo it is difficult to say with any assurance, but you could use the old plate with the bearings inserted in the holes. Get some transfer punches with diameters to fit the ID of those bearings and use them to mark the new locations. For the holes that have been distorted/enlarged your best bet is to examine the old holes to see which side the wear is most prominent on. Push the bearings against the OPPOSITE side when you use the punch to mark the new plate. With any luck, that may work. If not, you can do the same thing but add some shims on the "good" side of the old holes when you punch the second try at a new plate. The fit of the parts when you attempt to assemble the machine will tell you something about any errors in the locations.

Making the new part: Doing this job on a drill press is not something I would do. Holding any accuracy there is going to be difficult. I have a 20" drill press with a large table, but I would not try it there. This seems to be a mission essential machine that you are repairing. You should be able to justify the cost of a proper milling machine to management for this. An import mill can be purchased for a few thousand dollars and will make this job a lot easier. If that is not possible, I would suggest finding a machine shop that can do the job right.

As to tooling/drills, no drill bit will produce a hole that is good enough to properly mount a bearing, press fit or otherwise. You would need either a larger reamer or a boring head. I don't know the OD of your bearings but I am imagining around 2" to 4" or so, That is really out of range for drill bits. It could be done, but I wouldn't. And that also makes finishing it with a reamer a bit difficult. Reamers require drilling first and then reaming. This is a job for a boring head. And for a rigid set-up on a milling machine.

Finally, I would also consider a better, harder aluminum alloy or steel. There are hardened aluminum alloys that can be machined easily.

Jay96 said:

So the company i work for uses specialized shredders to make gift basket shred. I dissemble and put back together the shredders for maintenance. Were at the point where we need new plates that hold the bearings/gears and cutters. Ill post some photos. It uses 2 larger bearings that arent really suppose to be a press fit (incase shredder jams it wont snap anything) and after months of use the bearing holes widen due to the bearing bouncing around. Should they be press fit ? So how do i find the true center of the hole since they have became misshapened ? . We have simple tools here at work and best thing being a drill press. What drill bits ? Basically i have a blank block of aluminum and need to copy whats in the pic. All the holes as well.

Click to expand...