gantry

[MBG]

What are they? What do they do? Is it like a mill but with just longer x and y capacity?

[ViperTX]

basically...that's correct.

[cbass]

from Merriam-Webster

Main Entry: gan·try
Pronunciation: 'gan-trE
Function: noun
Inflected Form(s): plural gantries
Etymology: perhaps modification of Old North French gantier, from Latin cantherius trellis

1 : a frame for supporting barrels
2 : a frame structure raised on side supports so as to span over or around something: as a : a platform made to carry a traveling crane and supported by towers or side frames running on parallel tracks; also : a movable structure with platforms at different levels used for erecting and servicing rockets before launching b : a structure spanning several railroad tracks and displaying signals for each


In most routers you find on this site, the gantry is the part that reaches across the table and supports the spindle. They usually move relative to the table, though there are also fixed gantry-moving table designs. These latter types are more like your traditional mill, in which the table moves to give x and y and the spindle moves up and down to give z.

Carlo

[MBG]

What are gantries used to make?

[Ken_Shea]

MGB,
It is only part of a complete mill (in this case), in and of itself, makes nothing.
A gantry is only a type/method of support or bridge.

Ken

[Geof]

If you go to this link
http://www.haascnc.com/details_VMC_G...8#VMCTreeModel
you will see a picture of a reasonable sized Gantry Router (or Mill). As other posts have explained the gantry is the big bridge structure that straddles the table and moves on guideways down the side of the table. The link has a video download about halfway down the page and you can watch the machine running. Most of the people making their own cnc machines are making little gantry machines. The largest gantry machine I have seen was about 120 feet long and something like 20 feet wide. It was actually built in place and the table was on the floor. It is used for machining aircraft wing components. Gantry machines are often called gantry routers rather than gantry mills and I think this distinction is made because generally they do not have the same accuracy as a mill.