Vintage Windmill and Wind Generator Forum

On my 6' Dempster #12 the mast is 1 7/8" and the clamp (1227n) is 1 7/8" but the outside hole in the main frame (01201n) is 2", also the hole in the bearing cap (01255) is 2". The clamp holds the the mast tight but it seems that when the whole windmill unit sets in the bearing cap there could be a lot of slop or movement. Is this the way it is supposed to be? I could shim or weld the section of the mast that goes into the main frame and upper bearing cap, turn it down to fit. Good idea or not? Thanks, Tom

I think your good. The large size for 10 ft mills is 2 1/2. I measured mine for the bearing race and storm stay and they are 2
inches. you don't want a tit fight. Wouldn't do it welding. I only have seen two sizes made by Dempster. Someone else my know different. Smaller size 6 ft and 8ft, larger size !0 Ft.

Wayne what size is your mill? Thanks, Tom

Wayne , you are right on , my 8ft # 12 is a very early model , and 2" is correct , 10ft & larger is 2 1/2 "
and newer model #12 A & B are 2 1/2 in mast .

6 and 8 ft Dempsters take the same mast pipe, turntable, pullout tube, and pumprod. The neckpipe is 1 1/2 ,inch pipe. Pipe measures inside, tubing measures outside. Original Dempster neckpipe is sch 60. sch 40 is usually used for replacement. Must have the hole in the top lined up with the notch in the inside cutout of the lower bushing for the flatbar on the pullout tube. So...to match the hole in the top, there is a nib on the head/neckpipe clamp, which fits inside it. That nib can wear off over time, it is in the clamp half, not the head half of the clamp. It has to be there to go in hte hole of the neckpipe. You can barely get that clamp tight enough. I have broken many bolts making it tight, but never the clamp. NOT SO for the neckpipe clamp under the stormstay. The extra little bit of space in the parts is normal.

I had an 8 ft Dempster once. I use the Dempster top casting and bearing races and storm stays on several on mills. The work well. One of my Dempster set ups is for my 10 ft Standard.

I have changed over many mills to Dempster turntables, and Dempster pullout systems.