spherical fusor construction

[Jake Wells]

for my 6 inch sphere I have found these 8 inch conflate rings do they look good? I don't see any knife edges on them
http://www.mdcvacuum.com/displayproduct ... =m.1.1.9.1

[Richard Hull]

They do have knife edges. They are just not easy to see, but are shown on the dimensional drawing. Stock conflats for sure.

Richard Hull

[Jake Wells]

i dont see a weld lip in the center of the conflats I.D. how can i insert my hemisphere

[Rich Feldman]

It seems self-explanatory from the section drawings in datasheet.
The B dimension clears your tube or hemisphere's 6 inch OD.
The A dimension approximates your tube or hemisphere's ID.
What are you missing?

[Jake Wells]

so would you recommend buying those specific flanges that I found on that website for my core or do you recommend any other store online that has those flanges

PS for my sphere do I need rotatable or non rotatable conflate flanges

[Carl Willis]

The flanges you are looking at have been used by many other builders in conjunction with 6" architectural hemispheres. The only question for you is whether MDC has the best deal, since virtually every vacuum supply house carries this flange. You might compare with

-Kurt J. Lesker
-Duniway Stockroom
-LDS Vacuum
-eBay (sometimes has good deals listed)

to name a few.

Ask yourself if you actually need, or even want, the function offered by having a rotatable flange. The rotatable flange would enable you to turn one hemisphere arbitrarily with respect to the other, rather than set it up in one of the many relations offered by the bolt pattern. I can't think of a great reason for needing that ability. Certainly you would not get two rotatable flanges; if you want the rotation ability, you'd buy only one of that type.

-Carl

[Richard Hull]

Rotatable flanges can be a real hassle, not to mention the horrendous expense in the larger sizes as they have to machine two separate items for each flange. To save money, I would suggest getting fixed flanges with no threading, (through-holes), in either flange. (threading often adds a great deal to the cost and assembly issues.)

Unless you can get them surplus or used for lower cost, stay away from rotatable and pre-threaded flanges. Some folks like the convenience of a pre-threaded flange for one of the two flanges, but good old fashion hardware store bolts and nuts are just fine and lot cheaper than all that wasted cash in buying S.S., NF threaded hardware that can sieze and create issues for the non-vacuum purist.

Tip** Before welding and placing appendages to your hemispheres, make sure they are in a position that will not foul bolt insertion or removal. This is hyper-critical of pre-threaded flanges, if you go that way, as the bolts can only go in one way on such assemblies. By using nuts and bolts with through holes on each flange, if a bolt won't work due to an ill-considered appendage, just put the nut on that side.

It is all part of the critical design aspect of making a fusor chamber or any good vacuum system.

Richard Hull