Making Boxes with Threaded Lids Using a Threading Jig

Transcription

1 My Way of Making Boxes with Threaded Lids Using a Threading Jig Smoky Mountains Woodturners March 18, 2014 Jared Bruckner

2 Introduction Included in this Demo My procedure for preparing box blanks from wet wood My threading jig My Procedure for making threaded boxes Cutting 16tpi Threads Making a threaded box using rings of good wood Other methods of making threaded boxes Methods for making threaded boxes from diagonally cut laminated wood NOT included in this Demo Box design Decoration of boxes Hand-Chasing Threads 2

3 My Procedure for Preparing Box Blanks From Wet Wood 1. Start with 1/2 log normally 1-2 ft long 2. Rough cut with chain saw 3. Cut squares with table saw (Optional) 4. Mount between centers a) Round Easy Rougher b) Smooth (Optional) Oval Skew c) Make tendons Bedan d) Shape tendons for dovetail ½ Skew e) Part (Optional) Diamond parting tool & saw 5. Mount in chuck and: a) Part lid from base 1/16 parting tool b) Drill base Forster bit leaving 1/2 5/8 walls c) Finish hollowing Bedan 6. Repeat step 5 for lid 7. Dry a) Denatured alcohol overnight b) Drain outside 1+ hour(s) c) Dry inside 3+ days d) Kiln 5+ days e) Inside for 3+ days 3

4 My Threading Jig 4

5 My Procedure for Making Threaded Boxes Good Wood Blackwood 1.27 Boxwood 0.89 Lignum Vitea 1.26 Mopani 1.08 Bocote 0.85 Cocobola 1.10 Osage Orange 1.01 OK Wood Black Locust 0.82 Dogwood 0.82 Bradford Pear True the tendon, outside, & inside of blank, if needed. 2. Prepare lid see diagram on next slide. 3. Sand and finish inside of lid. 4. Cut threads in lid. 5. Determine diameter of tendon for base by adding 2mm to the inside diameter of the threads in the lid. Make a ¼ long tendon on the top of the base. 6. Prepare base see diagram (slide 6). 7. Finish hollowing, sand and apply finish to inside of base. The diameter of the inside of the base should be at least ¼ less than the diameter of the tendon. 8. Cut threads on base. 9. Adjust for grain match to about ¾ from true match. 10. Finish turning, sanding, embellishing, & applying finish to outside of box except for bottom of base. 11. Adjust for true grain match. 12. Finish turning, sanding, & applying finish to the box bottom. 5

6 Diagram for Threaded Boxes Recess (Optional) D Chamfer Lid F T = F + 2D Base For 16 tpi: D = to inches about 1 mm = inches 6

7 Cutting 16tpi Threads 1. When preparing the lid (base) make sure you leave enough wood to turn the threads and do the finish turning on the outside (inside) of the lid (base). 2. Position the lid (base) on the threading jig so that the cutter just makes contact with the surface of the wood in the cutting area while rotating the lid (base). 3. Back the lid away from the cutter and move the lid (base) toward the cutter. 4. Turn on the cutter and while holding the lid (base) toward the cutter with the left hand, turn the lid (base) to cut the threads. Be careful that the cutter does not make contact with the top of the lid (shoulder on the base). The optional recess on the lid (base) will help. 5. At the end of the cut, turn off the cutter and back the lid (base) away from the cutter. 6. Flow thin CA glue into the partially cut threads and let dry. Do not use accelerator. 7. On the lid move the lid toward the cutter and re-cut the threads. On the base re-cut then test the fit of the lid. If the lid is too tight re-cut until lid fits. 8. Lightly sand the threads. 9. On good wood the threading cuts can be made without using CA glue. One cut on the lid. Cut on the base first cut and repeat using cuts to fit. Putting wax, soap, or WD40 on the threading area before cutting may help. 7

8 Making a Threaded Box Using Rings of Good Wood 1. Plan for the thickness of the rings. About ¼ will be the thickness of external walls on the lid, about ½ will be for the two matching ring of good wood and ¼ will be for the thickness the base tendon walls. If the original box blank s walls are too thin, this is not a good method to use. If they are too thick you might reduce both the lid s and the base s wall thickness. 2. Hollow lid so walls are about ¼ the original (or modified) thickness. 3. Prepare a ring of good wood with walls about the thickness of the lid walls. 4. Use flexible CA to glue the ring in lid and when dry prepare as in diagram (slide 6). 5. Sand and finish inside of lid then thread lid. 6. Determined the size tendon needed for threads on base. 7. Cut a tendon of that size in good wood about ½ long and turn chamfer at end. 8. Cut threads on tendon to fit lid. 9. Cut about a 3/16 long tendon on base so walls on tendon are about ¼ the original (or modified) thickness. 10. Hollow tendon on good wood about ½ long and sized to fit tendon on base. 11. Part off ring of good wood about 3/16 long and place it on base tendon, but do not glue yet. 12. Thread ring for the base into lid and place lid on base and using tailstock to hold the lid in place, finish turn the outside near the base/lid join. 13. Spread flexible CA glue on the inside of the base ring and slide onto base so the you have grain match, then back off lid about ¾ and let dry. 14. When glue has dried tighten lid and proceed as usual. 8

9 Other Methods of Making Threaded Boxes 1. Using slow cure epoxy for threads: a. Cut slots in both the lid and base about 1/4 wide and 3/8 deep. b. Fill slots with slow cure epoxy (color may be added). c. Let dry 72+ hr. d. If epoxy shrinks too much fill again and wait 72+ hr. e. Prepare the lid as in the diagram (slide 6) so only about ½ the epoxy is left. f. Cut threads in the epoxy. 2. Using box type inserts made of good wood. 3. Using pre-made inserts. 9

10 Methods for Making Boxes from Diagonally Cut Laminated Wood Using box type inserts made of good wood or using pre-made inserts method, with the addition of a washer between the base and lid, will give reasonability good results. To achieve perfect match of the slats you must use the threaded rings made of good wood method. The trick of being able to achieve perfect match of the slats lies in the way you prepare the base and the lid. Base and Lid Preparation with Diagonally Cut Laminated Wood 1. When cutting the laminated block, cut the blank about ½ wider than the block is thick. 2. Mount the blank between centers and part the lid from the base while the blank is still rectangular. (Or cut on bandsaw or table saw.) 3. Align the slats in the lid with the slats in the base with the lid lapped over the base about ¾. 4. While in that position, mark on the base and the lid where the two parts overlap. It will be about ½ from the edge on both the base and the lid. 5. Cut those about ½ sections off both the base and the lid resulting in nearly square blocks for the base and the lid. 6. Use double-sided tape to attach the lid to the base and mount between centers. Be careful to find the centers on both ends of the lid and the base as the dimples made in step 2 are NOT the new centers in this step. Round the piece and cut tendons at the top and bottom. 7. Hollow both the base and the lid. (The base hollowing can be left until latter, if you prefer.) 8. Continue as in the treaded rings of good wood method. But, when cutting the tendon at the top of the base be very careful to make the tendon exactly the right length so that the slats match perfectly when the lid is placed over the tendon. The tendon is likely too long so cut to desired length and continue with the threaded rings of good wood method. A good time to get the length of this tendon correct is Just after the lid is hollowed and before the ring is glued in the lid. 10

11 References Bowers, Bill (2009). Turning Boxes with Threaded Lids. Atglen, CA: Schiffer Publishing, 80pp. Cook, Nick (2005). Threaded-lid Acorn: A fun project that won t fall far from the lathe. American Woodturner, 20.1: Holder, Fred (2001). Making Screw Threads in Wood. East Sussex: Guild of Master Craftsman, 133pp. Klein, Bonnie (1994). Screw-Top Boxes: Turning a box with a threaded lid. American Woodturner, 9.1: Peace, Mike (2013). Shopmade Threading Jig: Screw the lids onto boxes, jars, and urns. American Woodturner, 28.2: Raffan, Richard (2002). Turning Boxes. Newtown, CT: The Taunton Press, 153pp. Swanson, John (1999). Turning Threaded Boxes. Atglen, CA :Schiffer Publishing, 64pp. 11

12 The End 12