principal difference between type b and type d

[malarchy]

Hi,

I'm wondering if anyone can offer a history or outline the significant differences between Grampian type b1 and type d cutterheads.

is one better than another?

Thanks for any feedback

[petermontg]

Hi,

I'm wondering if anyone can offer a history or outline the significant differences between Grampian type b1 and type d cutterheads.

is one better than another?

Thanks for any feedback

I know type D is a feedback head, not sure about b1. i did try and find some info on them but the web seems to be lacking.

Maybe len could help you out
http://www.hrsrecords.com/

If you do find any info, dont forget to post it.

Edit: both are feedback, but there is two B1. the B1/AGU and the B1/A