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4. MITER CUTTING

To  TEACH  THE  USE  of Wood-working tools or any mechanical process without an actual demonstration involves many words. While the following has been made as concise as possible, repetition of rules may be found. Wherever it does occur it is because certain simple practices to produce good work are overlooked only too often.

The arrangement of the working quarters for miter cutting and joining is important. There should be a strong bench attached to the floor if possible, shelves for finishing materials and a convenient rack for tools. An efficient arrangement will surely reduce errors in measuring and cutting besides making for better work­manship generally. Once everything is in its place, proceed in an orderly fashion to do the work and replace all tools and equipment when finished.

If several frames are being made at once, complete each step for all the frames before proceeding to the next operation. Measure and mark all the molding strips, cut them into sections, cut the miters, size the joints with glue, etc. Naturally, if frames are being made regularly or a great many are to be made at one time, it will be more efficient to divide the work into groups. Measure, cut and miter all of one size or type first and then another.

When cutting miters preparatory to joining, the beginner is bound to make errors and to experience a certain amount of waste. Much expensive molding can be saved if experiments are conducted with pieces of scrap wood. The first attempts in frame-making should consist of cutting perfect miters, making strong, tight joints and then cutting wood to prede­termined lengths. The small amount of effort and time spent in practicing will be quickly repaid.

Care and good craftsmanship in frame-making have no substitutes. The experience gained in woodworking by solving framing problems in a functional way and actually making frames will gradually develop the faculty of choosing the correct profile of molding for each picture.

Before starting to cut the miters, it will be necessary to have a gauge of some sort attached to the miter box, provided the combination tool (which comes with a gauge) has not been purchased. No amount of careful marking will take the place of a measuring gauge and stop-block for cutting Moldings accurately to specified, equal lengths.

STOP  BLOCK

A yardstick, a small C-clamp and a block of wood, one end of which is mitered are all that is necessary to construct a primitive gauge that can be attached or removed quickly from the miter box. Suitable ex­tensions can be attached easily to accommodate larger frames.

The yardstick itself will have to be mitered at one end and then attached to the back of the miter box while the saw is in position for cutting. The simple stop-block should be thick enough to take up the dif­ference between the fence and the yardstick. Only enough of the block needs to be mitered to make for accurate measuring. When clamping it at a particular point, be sure that it is vertical. Once a cut has been made with it in position for one side of a frame, do not shift it until the other piece has been cut.

Before using the miter box and gauge for the first time with regular molding, try making practice cuts with scrap wood but remember that the depth of the rabbet will have to be taken into account. The attach­ment described is a rather crude affair and is shown merely to illustrate the necessity for such a device. More efficient gauges will undoubtedly suggest them­selves and should be worked out until they are as accurate as possible with the particular miter box being used.

The selection of molding is the first preparation for cutting the four sides of the frame. Always discard badly warped sections or those with other faults. The discarded pieces should be saved, however, for experimentation with decoration or for samples. It is a good plan, also, to cut the longest sides of the frame from the straightest and best parts of a length of molding. By measuring carefully and spacing the pieces proper­ly, waste can be reduced to a minimum. It will be found occasionally that after four sides have been marked from a piece of molding, the remaining sec­tion is just too short to be of any real use. To avoid this waste, particularly with the wider Moldings, it is more economical to cut three of the sides from one length of molding and the fourth from another.

At this point it is necessary to decide which of the two methods of measuring a picture for a frame is to be used. Matted pictures, prints or drawings or stretched canvases are more economically measured by taking the RABBET measure. This is the length that theback of the rabbet will be after the miters are cut, allowing, of course, extra for insertion of the picture. On the other hand, assuming that a picture painted on a panel measuring 20" x 24" is to be framed but that only an area measuring 19" x 23" be shown, it would call for SIGHT measure. This would be the measurement along the inside edge of the frame.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Whichever method is used the molding will be marked in the same manner because the beginner should not at this time attempt to take into considera­tion the depth of the rabbet. A little waste when first cutting miters is preferable to spoilage of a frame through inaccurate marking.

The first operation before actually cutting the miters is to mark the molding for cutting the four pieces straight across. (AA in drawing) This will make the work easier to handle. It is at this point that be­ginners are apt to make their first serious error because the width of the molding is not taken into considera­tion. Whether sight or rabbet measure is used, always add twice the width of the molding to the actual size of the picture plus enough to allow for insertion. This rule cannot be emphasized too strongly, so check and re-check before cutting.

Lay the length of molding face up on the bench with the rabbet side facing away. Assuming that the molding is 2" wide over-all and that a frame for a picture 16" x 20" is to be made. First add about ⅛”to the measurements to allow for insertion of the picture. Then add twice the width of the molding (4") to each measurement. The lengths that the molding is to be cut into are now 20⅛x 24⅛". After the molding has been marked and checked, it is sawn across from the top to bottom. Any splitting will therefore occur on the rabbet side and will be discarded with the waste from the miter cut.

Allow more or less extra for insertion or "play" for each particular job. For instance, space for insertion will necessarily be limited according to the depth of the rabbet. Again, on frames for stretched canvases or wooden panels, the extra length and width may be as much as ¼"to allow for contraction and expansion.

Another important rule to remember when cutting miters is that the molding must be held firmly so that it does not shift in the miter box. In addition, it must be placed absolutely flat against the base of the miter box, otherwise the miter will be cut at an angle to the molding and will not join. The sketch shows exag­gerated cuts.

Place the piece to be mitered in the box, face up, and with the rabbet side toward the front. The saw guide should be swung to the hit. Hold or clamp the molding firmly, insert the saw and bringing it down slowly start the cut. Proceed to cut one end off all four pieces in this fashion.

Next swing the saw guide to the light and attach the gauge. Set the stop-block at the proper point for cutting the longest sides first. Make the cuts as before but reverse the molding so that the rabbet is toward the back. Check the two lengths by placing them back to back. Unless they are exactly the same length, it is useless to overlook the fact and proceed to join them later. The frame will not only be wider on one side than another, but it will be impossible to make tightly fitting, accurately joined corners. The gauge should now be set for the two shorter lengths and the miters cut on them, checking the lengths as before.

Cutting for rabbet measure will make the "sight" of the frame smaller and cutting for sight measure will make the back of the rabbet longer.

A method for securing true miters, before the intro­duction of accurate miter boxes and mass-production tools for picture frames, was by the use of "shooting" boards. Miters were first cut quite roughly and later planed down to the exact length by using the boards. It was a good method in the hands of a skilled wood­worker, but its use is not really necessary today pro­vided cuts are made accurately with the miter box. The beginner, using a shooting-board, is apt to plane too much off first one end and then the other trying to make them equal. Something like sawing off first one leg of a tipping table and then another until there is nothing left. When a need for one is felt, a home­made affair will work just as well as an expensive, ready-made shooting-board equipped with a plane.

A shooting-board employing sandpaper instead of a plane will be found to give very smooth surfaces for excellent gluing work and will not remove enough of the wood so that the length is appreciably affected.

All that is required is one piece of wood 1" x 8" x 20" and another 1" x 6" x 20" fastened on top with one edge flush. On top of the assembly are fastened two small pieces, 1" x 1", as shown. They must be attached at exactly 450 to the top piece, otherwise the sanding block will cut the miter at a wrong angle thus pre­venting proper joining. Screw all parts together for durability.

The sanding block must be square and smooth. A piece of fir or pine 2" x 3" and 8" long will be suitable. It is necessary to make a clamping arrangement to hold the sandpaper smooth so that it will not have to be wrapped entirely around the block. Clamps to hold the paper can be easily made by cutting two pieces of wood ½" thick, 1¾”wide and 8" long. Place the paper around the block and fasten the two pieces to the top and bottom with ¾" countersunk screws.

Shooting-boards do not usually prove to be neces­sary except for certain woods or if the saw makes a very rough cut.

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