I have an antique cast iron sink with a 4" drain hole (raw opening in the sink). I am desperately seeking an adapter for the drain so that I can install a garbage disposer. I see mounting adapters on the Grainger site, but 4.5" is the smallest offered. If anyone out there has any recommendations or suggestions, I would be so very grateful. Thank you!

That 4 1/2" adapter would not work anyway. It is to adapt from a 6 bolt commercial disposer mounting flange. YOu probably have a Kohler sink from the days before they had disposers and Kohler made that sink to fit their 4" sink drain, and no others.

Thanks hj! If this was your sink, how would you attach a disposer? Appreciate the advice.

I do not think you can, unless the disposer flange is wide enough to not fall through the opening. You may have the same problem if you try to replace the drain with an ordinary one, which is also 3 1/2" wide.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



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But he doesn't have an ISE commercial connection with SIX BOLT HOLES to attach it.

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He would still need the ISE sink mount with six bolts to install it.

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hj is probably correct

Another possibility:

Have a flat s/s ring 'heliarced' to the insinkerator s/s flange then machined/polished flat and smooth.

IF the clamping bolt pattern will allow !

Use a thin 'spacer ring' (not welded on) to keep the new flange assembly 'centered'

Try a restaurant supply / fabricator shop.


mayyyybe about $100 - wild guess

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



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Those are NOT "clamping bolts". They are mounting holes which align with the holes in a commericial ISE disposer. The "mating surface" is a flange on the bottom of a "funnel" in the dishwashing prep[ area.

I meant to modify the standard flange


(you were correct to start with - i misread the ISE specs)

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

HOW would you do that, without drilling 6 holes in the sink and bolting the adapter to it? It would NOT be an easy task with a cast iron sink.



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I am not communicating properly.

I meant: use the standard consumer flange (which is s/s) and heliarc an 'extension ring' around it to increase the OD as necessary for the sink in question.

Then the OP would be connecting the standard consumer grade disposal.







the three jacking / flange screws will 'probably' secure against the triangular 'backing flange' IF ASSEMBLY CENTERED PERFECTLY - hence the 'spacer' washer need





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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



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He would have to be very desperate for a disposer to go through that. It would have to be a fairly thin material, AND the bottom of the rim would need to be "feathered" so water did not accumulate around it.

Quote

I am desperately seeking an adapter for the drain so that I can install a garbage disposer.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

The better long term goal would be to get a new sink and avoid all the foolishness.

A 4" drain was usually in a "farmer's sink".