DC connection for a shaper

I have a Grizzly 1.5HP shaper. I think i finally have designed a good dc connection out the back of the fence. This will have a 6" drop then a tapered wood hood to the back of the fence which is designed for a dc conenction on the back. Should I add a line to the top over the cutterhead or is that overkill with 6" line. I will try it without and see how it works.
There is still some planning to figure a method to block opening between the movable fences and the fixed center hood section.
Bill D.

I'm having trouble visualizing what you mean by the additional connection over the cutter head...good collection from the hood like you describe is likely going to do the job if the hood behind the fence is surrounding the cutter head as it generally would be. What am I missing?

I have seen some where they install a small hose vertical over the spindle. It seems like overkill to me. Maybe for a little router table where there is not much room for air flow.

You should be fine just going out the back. That's where the chips are heading for most cutters.

You want as much cfm as possible through the back. Running 250mm heads or climb cutting might benefit from a second drop but that isn't likely with that sized shaper. Dave

Reason I asked is I had a smaller sears shaper that had a small dust port on the back. it was barely as big as a shop vac hose and I added a rubber boot over the top for more flow. that helped some even if all I was using was a shop vac.
That rubber boot was made from a Bosch K-jetronic intake flex boot. car intakes like that are a good source of adaptable shaped hoses for dc hoods.
Bil lD.

Since you appear to be making your own hood, use 5 inch hose...........Rod.

Most of my shapers have an 8" pipe to them. 6" at the back and another 6" pulling through the table under the cutter. Not much escapes on a full cut since everything gets thrown straight into the hood.

A mistake I made early on was trying to choke off things so the cutter had fence all around it. You need to move air to move chips, closing things off too much doesn't benefit that cause at all.

Putting a pipe directly above won't do much.