a couple of tips with the HF vibratory tumbler (based on my experience)

- pay the $10 and get the 2 year replacement plan (I've already cashed in on this so it was well worth the purchase price)

- the wing nut that holds the top on will vibrate straight off (no matter how tight you appear to tighten it). after it flies off, the top will then vibrate like crazy and inner bolt post will cause the hole in the plastic lid to open up to the size of a quarter or 50 cent piece.
note: you can avoid this design flaw by picking up a couple of 1/4"-20 (course thread) nuts and securing the top as such: after putting the rubber & metal washer combo over the bolt, secure the 2 nuts (tightly) and then the wing nut. the 3 nuts together will not loosen and fly off now.

- I've used both the medium and fine walnut shells but I think that the fine media does a better job (tip: use a 25% off coupon when purchasing media too!)

- follow Triumvirat73's advice and purchase some flitz to toss in with the media (about an oz with every 3-4 loads of parts (the gallon size jug is the best value for the price, but only if you plan on tumbling a lot of parts. otherwise, go for the 16 or quart size container)

- don't be afraid to let the tumbler run for 5-6 days straight. you'll be amazed at how "new" the parts look after tumbling continuous for 100+ hours

also, don't bother to purchase additional bowls to hold different types of media. its far easier to dump the media out into a bucket and change it out then it is to remove the bowl from the motor.

well, tumbler no. 4 from HF "died" yesterday. time to cash in the replacement plan for the 4th time

it was working until I turned it off. with the lid off, I turned it back on to search for the last remaining parts and lo-and-behold, the motor was making a hum, but nothing was happening. that $10 replacement plan has now paid for itself 3x over.

ps
I fill the tumber to the top of where the inside of the plastic bowl ends (where the rubber and steel washer on the inside are). that seems to the total amount of media that HF gives you if you purchase a separate bowl.

with the HF tumbler, your total weight of the bowl (media and parts) shouldn't exceed 5lbs., otherwise you'll put unnecessary strain on the motor. I typically fill to where the bottom of the bowl comes up in the center (where the nylon nut attaches on the inside).

as far as any media "enhancer" like flitz, I typically add about an ounce worth and let it mix in a bit without any parts in the bowl so that you don't get any "wet" clumps on your parts.

I'm using the liquid. additionally, I'm using the flitz media additive, not the metal polish

I shake the bottle good before squeezing in a couple of rings of it into the bowl, turn it on [without any parts in it] and let it "blend" into the media for about 30 seconds and then add your parts to tumble.

the gallon sized container is the best value per ounce, however if you don't expect to tumble a lot of parts, then the next best value is the box of (6) 16-oz containers

their 18lb tumbler is a lot better built and has this feature already. it runs a lot quieter too, however it is 3x the cost of the 5lb tumbler