Each craft check represents 8 hours of work in a day. So in one day you could potentially have 3 craft checks, but at the expense of sleep. If you have dedicated time to craft, you could get away with 2 craft checks. If you're wondering, the 8 hours a day come from the magic item creation section which says that you can spend 8 hours in a day crafting a magic item, so it stands to reason the developers would have set a similar limit to regular crafting as well. Keep in mind, with the 8 hour limit, one could spend 8 hours forging a sword, then 8 hours enchanting a wand. I have a wizard with a Ring of Sustenance that does this very thing in his off time when the party needs items.
Hmm, you're reading selectively instead of the whole section. I'm going to quote the text I think is relevant.
To determine how much time and money it takes to make an item, follow these steps.
- Find the item's price in silver pieces (1 gp = 10 sp).
- Find the item's DC from Table: Craft Skills.
- Pay 1/3 of the item's price for the raw material cost.
- Make an appropriate Craft check representing one week's worth of work. If the check succeeds, multiply your check result by the DC. If the result × the DC equals the price of the item in sp, then you have completed the item. (If the result × the DC equals double or triple the price of the item in silver pieces, then you've completed the task in one-half or one-third of the time. Other multiples of the DC reduce the time in the same manner.) If the result × the DC doesn't equal the price, then it represents the progress you've made this week. Record the result and make a new Craft check for the next week. Each week, you make more progress until your total reaches the price of the item in silver pieces.
If you fail a check by 4 or less, you make no progress this week. If you fail by 5 or more, you ruin half the raw materials and have to pay half the original raw material cost again.
Progress by the Day: You can make checks by the day instead of by the week. In this case your progress (check result × DC) should be divided by the number of days in a week.
Now, what this means, at least to my reading is that crafting normally takes a week per check. So each check represents 7 days of work. However, if your Craft check results in a number double or higher than the price in SP, then you complete the crafting in half time, or faster (triple result = 1/3 time, quadruple result = 1/4 time, this is what it means by other multiples).
Now, lets say you wanted to figure out how long it actually took you to complete the item. Dive your result by 7, and that represents how much work you got done that day. So if you tripled the price in silver pieces, you would finish the item on day three during that week.
Now, as for making multiple checks in one day, I'd say the rules say no. The rules say how much you get done in a day, period, but doesn't give you a time frame of how long that day is. I use 8 hours as that is the number given for crafting magical items, but your GM could say 10, or 12 hours or longer. Whether or not you can make multiple checks in a day, is subject to GM approval, but I'm going to err on the side of caution and say the RAW answer is: No.