Screw type woodchipper

[jph]

Are screw type chippers any good?
I was looking at this one    http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=320314236993&ssPageName=STRK:MEWA:IT&ih=011

I will mainly be using it on conifer tops of less than 3 inch diameter.
Thanks John

[beenthere]

The terminology may be confusing (don't know), as it says "chopping" which implies a knife action.
Any other information that this is some type of "screw" ?

It is in the UK, so unlikely is it one you will bid on?

Should work on the 3 inch tops.

[woodmills1]

a google search of Sasmo HP-20, the listed chipper name and model, turns up 3 hits, none readable to me

[Ironman]

Never heard of a screw type, but it I searched the model and it is a drum chipper which is apparently oriented at an angle, giving it a screw appearance when looking down inside the infeed.  It is just angled to increase the efficiency of the cutting knives and to pull the material into the drum.  Drums are a very efficient type of chipper but they don't make an even chip size so you don't see them in bigger commercial units because those are used for pulpwood chipping and the chip must be of consistent size.  Drum chippers use less fuel and are less maintenance intensive than disc style chippers in general.  They are being widely used for fuelwood chipping.

This is a PTO-drum chipper that looks pretty simple.  Plenty of them here in the states though so I am not sure why anyone would buy one from England, used and then ship it here.