The original Throw-Away paper bags had a tapered vase trumpet opening so they could be pulled through the bag hubcap and flared before the swiveltop was latched on. Made an excellent dust seal tho the regular open wide top bags work fine as well flared around the rim under the 'hubcap'. The hubcap is essential for sealing to the swiveltop cap gasket or major leakage ensues. Hope your's came with that...
Dave
And what a powerful machine it is. Also much quieter than later GE models. It was a gift to me from Norm Brown when he was downsizing and moving. Thanks again, Norm!
Jeff