If I can image a drive to 95% will a head swap accomplish anything, or is this a symptom of irreparable platter damage?

Some more details would not hurt.
What are you using to image the drive. What for a drive is it. Where are the 5% of sectors that you can not image, at the beginning, middle or end of the drive? and what happens when you reach does bad sectors, can you see drive registers? any noise?

Quasimodo is right, you need to provide more details.
But I don't really think swapping heads will help you to get the 5%.

Some more details would not hurt.
What are you using to image the drive.

DI

What for a drive is it.

80G Toshiba laptop

Where are the 5% of sectors that you can not image, at the beginning, middle or end of the drive?

The MFT of course.

and what happens when you reach does bad sectors, can you see drive registers? any noise?

The usual busy regiters, noises.

The drive is no longer responsive, but I suspect a head swap would be a waist of a donor, since the heads successfully read most of the sectors.

Thanks.

Head swap won't help.

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data recovery Poland

try uping the read retries and last resort read without ECC