Hello there, Yogi.

I've got steps to ensure you can efficiently keep track of the costs for each potentially unique piece of equipment in QuickBooks Online.

To start with, you'll have to create individual inventory items for each piece of machinery. This is done to keep track of all machine components. To complete the process, you need first enable the Inventory tracking feature on your end.

Then, here's how to add each part of the machinery:

1. Click the Gear icon ⚙ and then Products & services.
2. Select the New button and select Inventory.
3. Fill out the required details like Name, SKU, and Category.
4. Choose the specific Income account and enter the sales price/rate.
5. Enter the purchasing information and cost of the item. Then, the particular Expense account.
6. Fill in the other needed information.
7. Click Save and close.

Once done, you can enter a bill transaction to record the auction purchase. You will then utilize the corresponding item created above and enter the exact cost as the expense amount. You can follow the steps below.

1. Choose + New and Bill.
2. From the Vendor dropdown list, select a vendor.
3. From the Terms dropdown arrow, select the bill's terms. This is when your vendor expects to be paid.
4. Enter the Bill date, Due date, and Bill no. as they're recorded on the bill.
5. Enter the bill details in the Category details section. From the Category dropdown, select the expense account you use to track expense transactions. Then enter a description.
6.  Choose the specific item in the Item details section to itemize the bill.
7. Enter the Amount and tax.
8. Fill in the other needed fields.
9. Click Save and close.

In addition, you may create expense entries to track the costs of repair and refurbishment. 

Furthermore, I also recommend consulting an accountant for additional guidance and they can provide you with more suggestions on how to properly handle the transactions.

In case you need different guidelines for effectively managing your business using QBO, you can read this article: Help guide for QuickBooks Online.

Feel free to add a comment below anytime whenever you have further concerns about managing your transactions or any QuickBooks-related concerns. I'm always here to help further, Yogi. Have a good day.