making a disc nut for an Ingersoll Rand 317 sander

[The Cobbler]

I have acquired an abundance of 4" sanding discs with a 5/8 bore . I hope to use them in my Iingersoll rand 317
but they are set up for a 7/8 bore . the threads are 7/16-20 on the shaft of the sander.
I am mixed between making a few nuts or trying to find something close .
One thing that would almost work is a weld nut but the collar is only 0.600 and I think the 25 thou undersize would make it enough out of round to be a pain.
amm I relegated to turning a nut or does any one have an idea?

 

[GeoBruin]

I have acquired an abundance of 4" sanding discs with a 5/8 bore . I hope to use them in my Iingersoll rand 317
but they are set up for a 7/8 bore . the threads are 7/16-20 on the shaft of the sander.
I am mixed between making a few nuts or trying to find something close .
One thing that would almost work is a weld nut but the collar is only 0.600 and I think the 25 thou undersize would make it enough out of round to be a pain.
amm I relegated to turning a nut or does any one have an idea?

I might be misunderstanding, but couldn't you just make a washer the same as (or slightly thinner than) the disc that takes up the space between the OD of the shaft and the ID of the disc, then use the nut to clamp down on the disc?

 

[The Cobbler]

the existing barrel of the nut is 7/8 od with 7/16-20 threads. the 4" discs have a 5/8 center hole

 

[Jswain]

I had a similar problem, but I didn't have that sander I wanted to use them on an angle grinder.

I ended up finding a 4" backing plate on amazon, and the matching nut, which was m10. Some Makita angle grinders you can find with an m10 arbor. I removed the arbor on one of my current grinders and turned/threaded it to fit.

Not ideal but depending how many you got might be worth it, or maybe you find an m10 arbor angle grinder easily.

Makita 224501-6 4-Inch Lock Nut https://www.amazon.ca/dp/B000GAX3H6?tag=atomicindus04-20

Makita - Pad Rubber 4 9501Bz (743009-6) https://www.amazon.ca/dp/B00018ABSC?tag=atomicindus04-20

 

[DHCrocks]

There should be a adapter for that, some of my grinding wheels came with a flat washer looking thing that fit inside the disc for smaller spindles. not sure what its called though.

 

[GeoBruin]

There should be a adapter for that, some of my grinding wheels came with a flat washer looking thing that fit inside the disc for smaller spindles. not sure what its called though.

That's what I was saying, but the nut has a barrel that sticks down that is larger than the ID of the discs. No reason you couldn't use any old 7/16" nut though.

 

[The Cobbler]

the shaft of the sander is 7/16 . the holes in the 4" discs are 5/8 " . in the 5" discs they are 7/8" . the nut that comes with the sander is 7/8 od on the shaft .
I don't see how any old 7/16 nut will align the discs with a 5/8 center hole, I think it needs a shoulder to align .

 

[GeoBruin]

the shaft of the sander is 7/16 . the holes in the 4" discs are 5/8 " . in the 5" discs they are 7/8" . the nut that comes with the sander is 7/8 od on the shaft .
I don't see how any old 7/16 nut will align the discs with a 5/8 center hole, I think it needs a shoulder to align .

What we're saying is the nut that clamps the disc down doesn't have the be the same piece that fills the gap between the 7/16 shaft and the disc. For the factory nut, that is the case, but it doesn't have to be: washer/spacer with 7/16" ID and 5/8" OD on the shaft, then a 7/16" nut with a fender washer to hold the disc down.

 

[The Cobbler]

ok, sorry for being dense ... I get it now . I guess I'd rather have one pc, but this is a real simple cost effective solution

 

[GeoBruin]

ok, sorry for being dense ... I get it now . I guess I'd rather have one pc, but this is a real simple cost effective solution

Oh no doubt, 1 piece is the way to go. It just sounded like you didn't want to spend an hour standing at the lathe. If it was me, I would spend two hours on the lathe, because I would screw up the first one and then have to make a second.

If you have to spend half that much time turning a washer anyway, you might as well go full tilt and make the custom part you need.

 

[RTM]

I would spend two hours on the lathe, because I would screw up the first one and then have to make a second.

If you have to spend half that much time turning a washer anyway, you might as well go full tilt and make the custom part you need.

Buddy of mine would do it just for practice, then give away the practice piece, and then make himself a nice one. I have a few nice custom widgets from his days at the lathe

 

[DHCrocks]

here's a couple of discs that came with adapters in the package.

here you can see the gold colored adapter that fits into the disc for reduced diameter shafts. Its a press fit. don't know what it is but maybe brass?



this one came with an silver looking one. I think its aluminum.

 

[GeoBruin]

here's a couple of discs that came with adapters in the package.

here you can see the gold colored adapter that fits into the disc for reduced diameter shafts. Its a press fit. don't know what it is but maybe brass?



this one came with an silver looking one. I think its aluminum.

I think that's the idea. The issue is those discs are meant to be used on a grinder with a backing nut that has a raised lip that fits the ID of the disc, or of the adapter. Then you just screw a flat nut down on top to hold the disc.

On his IR sander, there is no such backing nut. The nut that screws down to hold the disc doubles as the spacer between the threaded shaft and the ID of the disc. So his only options are make a replacement nut with a different size spacer, or to find/make a spacer and use a separate nut to clamp it down.

 

[The Cobbler]

So his only options are make a replacement nut with a different size spacer, or to find/make a spacer and use a separate nut to clamp it down

this

 

[The Cobbler]

washer/spacer with 7/16" ID and 5/8" OD on the shaft, then a 7/16" nut with a fender washer to hold the disc down.

more thought on that idea, it won't actually work in this case because the shaft is flush with the top of the sanding disc so a nut won't grab it to thread on, it needs to be a shoulder nut that is threaded 7/16-20
guess I'll need to go to work on the lathe sometime
I've got some old chevy wheel lug nuts , they may make a good start to the project

 

[GeoBruin]

more thought on that idea, it won't actually work in this case because the shaft is flush with the top of the sanding disc so a nut won't grab it to thread on, it needs to be a shoulder nut that is threaded 7/16-20
guess I'll need to go to work on the lathe sometime
I've got some old chevy wheel lug nuts , they may make a good start to the project

You could just turn down the nut you have and order a replacement for that one. Might save some steps.

 

[RTM]

You could just turn down the nut you have and order a replacement for that one. Might save some steps.

Turn it down, then put a bushing on it?

 

[GeoBruin]

Turn it down, then put a bushing on it?

No need. The existing nut has a 7/8 OD barrel. The discs have a 5/8 hole. Just turn down the barrel and Bob's your uncle.

 

[GeoBruin]

No need. The existing nut has a 7/8 OD barrel. The discs have a 5/8 hole. Just turn down the barrel and Bob's your uncle.

Oh, I see, you're saying you could put a bushing on to run 7/8" discs again. That's a good idea.

 

[The Cobbler]

semi related thread here

 

[The Cobbler]

No need. The existing nut has a 7/8 OD barrel. The discs have a 5/8 hole. Just turn down the barrel and Bob's your uncle.

yes, but then I lose the ability ( without using a bushing) to use 7/8 hole discs.
however, I was in Habitat today & in a plastic bag on their odds & ends rack was a sander disc nut. I bought it for $1 , but it turned out to be a 10MM ( I think ) thread. no problem, off to the lathe , drill & tapped it to 7/16-20. now I can turn the 7/8 down to 5/8 and have all bases covered

 

[The Cobbler]

Update
I ordered some 7/16-20 weld nuts like this

the outer part of the collar measures .590 , so a tad under from 5/8" but it seems to be snug enough to hold the disc evenly enough not to cause an imbalance .

here it is installed with a 4"x5/8" disc on it. hoping to test run it later today .
I am also contemplating ordering some sander nuts that are unknown size, just that the center hole is a bit over 3/8"

 

[The Cobbler]

put a 4" 24 grit sanding disc on & ground some rusty metal with it. the nut works like a charm .
Hope someone else can use this information .