I was in QA for too many years - all I think about is what can go wrong.  I'm thinking about following the Form 1 trail and building my own suppressor, and I'm paranoid about the subjective way a lot of regulations get interpreted.  Didn't know if anyone had some definitive answers to allay my concerns

Construction won't start until I get my stamp but what about the initial purchase of parts?  And do I have to wait until I screw up a part (threading the tube, punching the baffles, whatever) to buy a replacement?  Is a drawer full of freeze plug and O-rings "constructive intent" for the ATF?

For that matter, what happens down the road if I have a baffle strike or the blast chamber just starts to show wear?  Do I have to notify the ATF that I, as the "manufacturer," will be performing repairs?  Or do I need to destroy it and start all over with a new Form 1 and $200 tax?

You can have all the parts you want on hand as long as they aren't silencer parts. Most of the DIY build parts are repurposed flashlight parts, car parts, etc... none are considered silencer parts till you modify them for the intent of being silencer parts or actually use them as parts of a silencer.

Once you build it and it's finished you can't legally repair anything yourself. The tax paid is only permission to make one silencer unit. Once it's made you can't make replacement parts because that's considered a separate instance of "making" and requires another tax stamp. You can get it repaired by an SOT though, but the cost might be prohibitive compared to paying another tax stamp and doing it yourself. Only wipes that are designed to be consumable are allowed to be replaced by anyone. Wipes are generally rubber or leather and make contact with the bullet when it passes through.

People will argue semantics of several ATF letters that have been passed around but what I said is the general consensus. With the ATF nothing is concrete, unfortunately, but generally if you're not pushing the grey areas of legality you're not going to get in trouble.

Of course I can not speak for the ATF but a threaded tube seems okay to have on hand to me. A tube is a tube. However, I would definitely not drill or form any baffles until the stamp is in hand approved.

basically the way I see it, and again its just my own opinion, if the parts you have on hand currently can be put together as is and attached to a firearm to effectively suppress it, it is constructive intent.

Thanks.  I wish you could use simple logic to make judgement calls like this but there's so much "agenda voodoo" involved that you never know what may run you afoul.