Miniature Molder/Shaper

 

Overview:

Duplicating minature moldings can be quite complex.  If only one or two bits are needed, it can be done with a reasonable amount of setup and work.  If the molding is complex, it can be created by adding several simpler moldings together into a composite molding.  But for real ease of use and repeatability with a minimum amount of setup, having a single molding / shaper cutter which will create the entire molding with one tool / bit is the best solution.  In 1/12 scale, scale 6 inches is 1/2 inch.  This is a relatively small cutting surface to work with which will create a rather large scale molding.

A molder and a shaper are used in similar but not identical ways.  A molder tends to carve the surface of a board with edge modification.  A shaper tends to carve the edge of a board with some surface modification.  My first project was the creation of a miniature molder.  I figured the bit creation would be much easier although I later plan on making my own shaper bits.  As my metalworking skills are basically nonexistent at the moment, I looked for a commercial tool which could be modified to work as miniature molder.   A rosette cutter for use in a drillpress seemed to best fit the bill.  The jesada rosetter cutter has a slot to hold a 1/8 in thick rosette cutter which cuts from the face of the holder.  If a similar piece of metal was substituted for the rosette cutter and made to cut on the edge, it would function as a 1 cutter molding head.  Images 1 - 4 fully explain how it works.

My index project was the duplication of a picture frame in my family room - image 5.  I made two different cutters - the first out of broken, hardened metal cutting blade, the second out of 1/8 in low carbon steel from Home Depot. (images 6 & 7).  I first drew a to scale outline of the molding I want to make on graph paper.  I bought 10 squares / inch and then reduced it by 50% to 20 squares / inch.  My 1/4 in wide frame would be 5 squares wide.  It is very hard to draw much detail at this size, even with a 5mm pencil.  The second drawing was drawn on the full scale paper covering 5 squares - 1/2 inch and then reduced to 1/4 in.  This allows more detail with a my pencil.  Compare images 6 & 7.  The drawing is glued and taped to the metal - image 8.

My primary cutter shaping tool is the dremel abrasive cutoff disc - image 9.  It is a little thick at times, even with disc shaping with the dremel abrasive cleaner block.  I also used diamond coated bits to shape the hardened steel.  They sort of worked but it was very slow going.  I need to get very handy with cutoff disc.  The non-hardened steel could be easily modified with regular needle files as well as the cutoff disc.  Images 10 - 13 document the stages of creating a bit.  This fairly soft steel cutter held up well and created over a dozen 7 inch long strips of molding with no appreciable dulling.  Hardening the bit with a torch might improve its durability but a higher carbon steel should probably be used.  Follow the supplier's recommendations for hardening tool steel.  This bit I heated to cherry red and quenched in water - image 14.  The bit made of hardened steel required no further manipulation.

Images 15 - 17 show my different molding head setups.  I have a Shopsmith which allows the same machine to have the drill chuck in either a horizontal or vertical position.  I chose horizontal as I could use the table saw fence and molder cutout.  Most people would use this in a vertical position and a vertical fence would have to be made.  It is not a big deal as many folks with a drill press already have this jig.  My miniature overhead shaper runs too fast and won't take a 1/2 in arbor.  I think the drill press setup should work just as well.

Image 18 is a sample board after running it through the molder.  I rabbeted the inside back edge of the picture frame molding - image 19.  I cut off the outside waste - image 20.  The molding was separated from larger piece of wood - image 21.  The two sample moldings are seen in image 22.  

As you can see, it is fairly easy to make a new cutter.  One cutter molding heads would not work too well on full sized pieces of wood, but for miniature moldings they work quite well.  There are advantages and disadvantages to working with different types of steel.  The best of both worlds is probably 1/16 in X 1/2 in high carbon steel with final hardening.  I will probably try that for my next cutter.  

Any comments or criticisms are welcome.  My next tool project will be a homemade shaper cutter for any dremel type tool.  

 

Jesada Rosette Cutter - 1

  1. This is a 3 in disk with a full width 1/2 in deep slot.  The cutter is held in place with a wedge.  It can accomodate up to a 1/8 in thick cutter.

Jesada - Side view - 2

  1. Side view with a rosette cutter in place.

 

Jesada - Top view - 3

  1. Top view with a rosette cutter in place

 

Jesada - Full view - 4

  1. Full view with a rosette cutter in place

 

Black Picture Frame - Family Room - 5

  1. This is the picture frame I am trying to duplicate.  It is quite complex and would require multiple simple bit changes without a specially created bit.

 

Bit #1 with Drawing - 6

  1. This broken blade was about 3/4 in wide which later needed to be trimmed down to 1/2 in because of my machine setup.  Next time I will use a 1/2 wide hacksaw blade.

 

Bit #2 with Drawing - 7

  1. This is 1/2 in X 1/8 in flat piece of steel from Home Depot.  I am sure it is not tool making quality and is low carbon but it is cheap and readily available. 

 

Bit #2 with attached drawing - 8

  1. The drawing is glued with rubber cement and duct tape is wrapped around the bottom. 

 

Abrasive cutoff disk - 9

  1. This is the only really effective tool for shaping the hardened steel cutter.  It also makes fast work on the regular steel. 

 

Bit #2 - initial shaping - 10

  1. The paper outline is still attached.  You can see the the thickness of the cutter which will have to ground down to a cutting edge. 

 

Bit #2 - inked surface for grinding - 11

  1. The surface is inked to be better seen with it is ground down to a cutting edge.  You don't want to grind the surface of the cutter and change your bit profile. 

 

Bit #2 - initial bevel - 12

  1. The cutter has an initial bevel.  The non-cutting portion of the cutter has be cut away below the level of the cutter.  No bevel is needed here as it will not touch the wood.  This bit will actually cut but there is too much tearing the the wood surface - it is a extremely dull bit. 

 

Bit #2 - final bevel - 13

  1. The grinding was primarily done with a dremel abrasive bit.  You can seen the arc the wheel put on the bit.  I honed the edges - bevel & face on a hard arkansas stone.  This thicker bit required significantly more grinding time. 

 

Bit #2 - hardening - 14

  1. Heat the bit to cherry red and quench in water.  You only need to heat the cutting portion of the steel and not the entire length.   

 

Molder Setup #1 - 15

  1. This setup used the cutter off the edge of the table.  It worked fine.  

 

Molder Setup #2 - 16

  1. This setup used a molding insert for my tablesaw.  I needed to cut the width of the first cutter down to 1/2 in for this to work. This turns out to be my best setup.

 

Molder Setup #3 - 17

  1. This setup used a wooden fence with a cutout.  The gap is too long for the length of boards I was using.  I tried using a hold down for keeping the board flat against the table.  It would only work with fairly good pressure from the fingerboard.  When the wood passed through, the cutter tried to eat the fingerboard.  So I use plastic pressure block to pass each piece of wood by hand. 

 

Edge of sample board - 18

  1. This is a sample board after passing through the molding head.  There is waste material on both sides as I can't place the aluminum fence close enough to the cutter head.  This is definitely safer. 

 

Picture frame rabbet  - 19

  1. The overhead shaper is placing a rabbet in the back of the molding.  Look at the edge closely and you can see the molding on the bottom side. 

 

Trimming outside edge  - 20

  1. The molding is flipped back over the the outside waste is trimmed off.   The molding is still attached to the larger board for easier handling - keeping all fingers intact. 

 

Separating molding  - 21

  1. The molding is now separated from the larger board.  The trim is cleaned up with files and sandpaper.  The board edge is run through a jointer and is ready for making another trim piece. 

 

Final moldings  - 22

  1. The left molding was made from the hardened cutter.  The right molding was my second with more exaggerated markings.  Actually the first one is more true to the original. 

 

 

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