StoredProc Insert Into Composite Key Table

I have three tables that are important here, a 'Plant' table a 'Spindle' table and a 'PlantSpindle' table. The 'PlantSpindle' is comprised of a PlantID and a SpindleID acting as the Primary Key for the table with no other fields.

I have an aspx page that captures the appropriate data to create an entry in the Spindle table. Depending on the user, I will know which plantID they are associated with via a querystring. In my storedproc I insert the data from the webform into the Spindle table but get stuck when I try to also insert the record into the PlantSpindle table with the PlantID I have retrieved via the querystring and the SpindleID of the spindle record the user just created. Basically, I am having trouble retrieving that SpindleID.

Here is what I have in my storedProc (truncated for brevity).

CREATE PROCEDURE [dbo].[InsertSpindle]
@plantID int,
@spindleID int,
@plantHWG varchar(50),
@spindleNumber varchar(50),
@spindleDateInstalled varchar(50),
@spindleDateRemoved varchar(50),
@spindleDurationMonths float(8),
@spindleBearingDesignNumber int,
@spindleArbor varchar(50),
@spindleFrontSealDesign varchar(50),
@spindleFrontBearing varchar(50),
@spindleRearBearing varchar(50),
@spindleRearSealDesign varchar(50),
@spindleNotes varchar(160)

AS
SET NOCOUNT ON
INSERT INTO Spindle
(plantHWG, spindleNumber, spindleDateInstalled, spindleDateRemoved, spindleDurationMonths,
spindleBearingDesignNumber, spindleArbor, spindleFrontSealDesign, spindleFrontBearing,
spindleRearBearing, spindleRearSealDesign, spindleNotes)
VALUES
(@plantHWG, @spindleNumber, @spindleDateInstalled, @spindleDateRemoved, @spindleDurationMonths,
@spindleBearingDesignNumber, @spindleArbor, @spindleFrontSealDesign, @spindleFrontBearing,
@spindleRearBearing, @spindleRearSealDesign, @spindleNotes)

SET @spindleID = (SELECT @@Identity
FROM Spindle)

INSERT INTO PlantSpindle
(plantID, SpindleID)

VALUES
(@plantID, @SpindleID)

I have guessed at a few different solutions but still come up with Procedure 'InsertSpindle' expects parameter '@spindleID', which was not supplied when I execute the procedure.

Any help would be appreciated! thanks!