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The Kruger Eccentric

Instructions for Use of the Dual Taper Reel Seat Filler and Eccentric Reel Seat Recess Turning Mandrels

Rick Kruger

503-860-6346 krugerr@easystreet.net

The Dual Taper Reel Seat Filler (Kruger Eccentric) allows turning straight, cylindrical reel seat fillers of various lengths and with any through hole size from just under 5/16” to just over 9/16”. This is one of the beauties of this mandrel set, as you can size the hole to fit your rod either allowing for less bamboo to be removed from the corners or less masking tape for building up the diameter. Depending on the size of the hole, the length of the blank can be from just over 3 ½” for the smallest hole to over 6” for the largest hole. The Dual Tapers hold the filler blank from both ends resulting in less chance of the filler slipping during turning. The Eccentric Hubs allow for turning of reel seat foot recesses without removing the filler from the Mandrels. Using the Eccentric Hubs, the filler will rotate in an eccentric fashion allowing you to turn the reel seat foot recess using the same tool as used to turn the straight filler. The Mandrels are offset from center by 0.100”. Parts of the Dual Taper Mandrels

Fixed Taper and Shaft

Sliding Taper

Fixed Taper Eccentric Hub Sliding Taper Eccentric Hub

5/64” Hex Key

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Turning a Cylindrical Reel Seat Filler

1. Prepare the blank to be turned by drilling the desired size hole in the blank by whatever method you prefer. I prefer to center the blank in a 4-jaw chuck on the lathe. With thicker blanks (~1”) less care is required for centering and/or wandering of the drill than when blanks are thin (~3/4”). I sand the blanks to get them as smooth and straight and parallel to the opposite side as possible, taking care not to remove too much material. Then I chuck the blank in the 4-jaw chuck with the smaller end out to allow more precise centering of the more critical end. I often bore, rather than drill, as deep as possible to ensure a good straight hole. On thinner blanks I often bore undersized holes from both ends and then join the holes with an undersized drill, and then drill to the final size.

2. Slip the Fixed Taper and mandrel shaft into the blank and press the taper into the hole with enough force to secure it but not so much as to risk splitting the blank.

3. Slip the Sliding Taper onto the shaft. Adjust the set-screw on the Sliding Taper to be as snug as possible while still allowing it to slide freely.

4. Press the Sliding Taper into the blank firmly enough to prevent rotation of the blank but not so much as to risk splitting the blank. I do not recommend tightening the set screw on the sliding mandrel. You want the pressure from the tailstock center to continually press the tapers into the blank, just make sure it isn’t so great as to crack the blank.

5. Chuck the Sliding Taper into a collet or scroll chuck. You can use a 4-jaw chuck also, but you had better be good at centering parts held in a 4-jaw as having the mandrel running true and concentric is important.

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6. Mount your tailstock center in the tailstock and bring it up to mate with the countersunk hole in the end of the Fixed Taper.

7. Mark the location of the Eccentric Hub locating flat on the end of your blank so you can tell if the blank rotates during turning of the Eccentric Recess. I found this to be necessary so I am pressing the live center harder into the blank to prevent rotation.

8. Begin turning the filler as you usually do, to your desired unfinished diameter. If the blank rotates or spins on the mandrel, press in harder with the tailstock center or take lighter cuts. This would be a time to account for the amount of material that may be removed during sanding and for the thickness of your final finish. If you end up with at taper over the length of the filler, one of the ends is not lined up with the lathe centerline, either there is runout or poor centering in the chuck or the tailstock is not properly aligned.

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Turning an Eccentric Reel Seat Foot Recess

1. Remove the Dual Taper Mandrel and straight turned reel seat blank from the lathe, but do not remove the filler from the Mandrels.

2. Place the Eccentric Hubs on the Fixed and Sliding mandrels, lining up the set-screws with the flats on the Mandrels. Secure the set-screws, locking the Hubs on the Mandrels. The Sliding Eccentric Hub has a ½” through hole while the Fixed Eccentric Hub has a blind ½” diameter hole.

3. Mount the Eccentric Hubs/Mandrel assembly

in the lathe and bring the tailstock center up to the center drilled hole on outboard end of the Fixed Eccentric Hub. Press the tailstock center into the hole in the Fixed Eccentric Hub with light pressure using the tailstock ram and lock it with the locking lever. It is best to use a live center. If you have left the Sliding Mandrel set screw unlocked, be sure the live center applies enough pressure to keep the blank from slipping. If you use a dead center, it may be best to lock the set screw on the sliding taper to maintain the grip of the tapers on the blank and use only light pressure and ample lubrication on the dead center.

4. Turn the recess using a radiused HSS form tool, under carriage power if you have it. The radius pictured is 3/8” and produces a tight curved transition from the recess to the full diameter. Larger radiuses would produce a more gradual transition. It is a matter of practice learning when to retract the cutter as the carriage approaches the transition point. It is useful to establish some sort of reference point, or use a travel dial indicator on the carriage.

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5. Retract the carriage and cutter to allow room to measure the distance across the recess to the full diameter on the back side of the filler, using either a micrometer (my preference) or caliper. This measurement minus the full diameter dimension is the depth of the eccentric recess.

6. As you approach having removed 0.080” –

0.090” resulting in a measurement of about 0.600” you will want to check for the fit of the reel foot. Retract the tailstock center and remove the Fixed Eccentric Hub to slip on the sliding band. If more turning is needed, reinstall the Fixed Taper Eccentric Hub and tailstock center and take off more material.

7. Once you have the fit you want, take off additional material to account for the thickness of the finish you plan to use as necessary. You can use a shim to simulate the thickness of the finish you intend to use. A nominal piece of copy paper is about 0.004” thick, but may be too compressible (not pictured).

8. Your finished eccentric recessed filler should look something like this.