Buy an old scissor jack at a second hand store, the "scissor" jack in the picture will spread of close chain stays. If you so choose, you can use two clamps to ensure the dropout's inner faces remain on two precisely parallel imaginary planes throughout the cold setting process.
**Golden Jack is a Mercedes jack, I have it air mail it back to Germany for recalibration every couple of years, they tell me they can do in in the states nowadays, but I don't want M class, GL class, or even an R class mechanic coming within two meters of that jack. I painted the Golden Jack because its the only tool in the shop that's paid for itself.
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