How to Make a Pattern Copier For Your Woodworking Lathe

Lathe pattern copiers are expensive and are not available for many wood lathes. Pattern copiers are used to make duplicate turned spindles from an original. Here's how to make your own.

You will need a piece of 1/2 aluminum tubing as long as your lathe bed or a bit longer to make your lathe pattern copier. You will also need some 1/8" thick aluminum sheeting or you can buy some aluminum cookie sheets. Purchase a box of 10-40 bolts 1 1/2" long and a wing nut and washer for every bolt. Buy a second box of 10-40 bolts 1" long with nylon-lined lock nuts for every bolt. You will need (4) 3" angle irons with screws, as well. The rest of the parts for your lathe pattern copier can be made out of any scrap wood you may have laying around the shop.

The design of this lathe pattern copier incorporates multiple feeler "fingers" suspended behind the lathe along the aluminum pipe. These fingers are adjusted to match the exact depth of the cuts in your original turned spindle. When you place a new spindle blank on the lathe, all of the lathe pattern copier fingers you adjusted will be laying on top of the blank. As you cut into the blank, prepare yourself to stop cutting as soon as the fingers relating to that cut drop down and through the cut.

Make two, vertical support posts about 6" higher than the top of the largest spindle blank you can turn on that lathe. Note the outside diameter of the aluminum pipe and drill a hole of that size near the top of each support post. Mount the posts using the angle irons on the lathe table immediately behind the lathe. Insert the pipe through both holes to make sure it fits.This will help position the aluminum fingers of your lathe pattern copier so that they can reach the spindle you are turning.

Make a bunch of wood blocks 3/4" x 1ï؟½" x 6" long. Drill a pipe sized hole in one end of each of them through the ï؟½" thickness. With the blocks lying flat, cut through from the end into the hole with a 1/8" table saw blade. With the blocks standing on edge, drill completely through each block between the hole and the end of the block. Use a drill diameter slightly larger that the shaft diameter of the 10-40 bolts. Insert one 1 ï؟½" 10-40 bolt through the hole you just drilled and place a wing nut and washer on the end. The idea is that the wooden blocks will slip onto the pipe and the bolts and wing nuts will hold them in place by closing up the 1/8" cut you made on the table saw.

Drill another bolt hole of the same diameter about 1/2" from the other end of the block, centered with the block laying flat on the drill press table. Cut another 1/8" slot, 1" deep and centered through the 1ï؟½" dimension, at right angle to the bolt hole. Remove one end of the pipe from the vertical support posts. You can now mount the blocks along the pipe before replacing the pipe in the vertical support post of your lathe pattern copier.

Cut aluminum fingers out of the flat stock using a 1/4" blade on the band saw. The fingers should measure 6" long and 3/4" wide. Both ends should be completely rounded (3/8" radius) on an edge, belt or disc sander. Drill a 10-40 bolt hole in one end of each finger centered 1/2" from the end. Sand the fingers smooth, removing saw marks and burrs.

Mount the aluminum fingers onto the ends of the wooden blocks, securing them in place with the 1" 10-40 bolts and lock nuts. The aluminum fingers must be free to move up and down.

Now place your original spindle on the lathe. Set the fingers to just drop through, barely touching the depth of each cut. Place the first blank on the lathe with the fingers you just adjusted resting on top of the spinning blank. Start cutting and stop as each finger falls through.

Bob Gillespie

Woodworker

ï؟½2010 Robert M. Gillespie, Jr.

Basic Pattern Making In The Hobby Foundry

Success or otherwise in your hobby foundry will depend to a large degree on your skills & ability to create simple patterns, i.e.

Patterns that are easy to mould, lift or separate from the sand

mould after a gentle rap.

A pattern that has incorrect draft on vertical surfaces, badly finished corner fillets, or a pattern that has not been finished to an ultra smooth finish will be difficult to work with.

Pattern making is an art in itself, pattern making

apprenticeships take around three or four years to complete, before you are given your "Trade Ticket".

The average hobby foundry worker most likely won't have the time, or the patience to get involved with the art of pattern making to that extent.

But the basic skills are worth the effort to learn, because

without them you wont get far with your hobby foundrywork, unless you PAY to have all of your patterns made for you, but that would take all of the fun out of it, and also cost you a sizeable amount of money.

Construction costs of professional pattern making can vary from a few hundred dollars for simple patterns, up to several thousand dollars for complicated pattern designs.

I happen to a know a pattern maker who designs and builds patterns & core boxes to make alloy & cast iron cylinder heads, it is not unusual for pattern & core costs to be around $20,000.00 AU before you even think about melting & pouring any metal.

If you are a legacy of the old tech school system of the sixties

& seventies, there is a good chance that you still remember how to skilfully use woodwork hand tools.

Some of the finest foundry patterns were made using basic hand tools. More than likely you still have a chisel set tucked away in a drawer, or a spoke shave, wood plane & handsaw, plus

a host of other tools that could be used to make excellent patterns in the home hobby shop.

And if they happen to be a bit rusty, then get them out again and bring them back to life, re-grind the cutting edges and hone

them with an oil stone.

Remember what your trade teacher always told you; "sharp tools

give the best results."

Do the same with the wood plane and any other tools, such as a small set of carving chisels you could use to carve intricate shapes in wood.

You'll need some good pattern timber or lumber as it's called in the states... doesn't matter, it's all wood isn't it. There are many types of timber suitable for pattern making, but, you'll probably be limited to what's available in your area or region.

Quality pattern timber is expensive to buy, so ask for off cuts at the local timber merchant, which you may get for a considerable discount

You'll be looking for a soft timber that doesn't splinter, has a straight grain, is easy to work or carve, and finishes to an ultra smooth finish.

One of the easiest timbers to use is jelutong, this timber comes from the Philippines, I don't know whether it is from plantation timber, or old growth forests, but it is great to turn on a lathe, or shape and carve with sharp hand tools.

Some of the other pattern timbers in use are cherry wood, mahogany, maple, white pine, and many others.

Quite often a master pattern can be made from timber, and then a replica mould is made using RTV 585 silicone, this is a quick method to remake replica production patterns.The replica patterns can then be mounted onto a match plate along with the runners & gates, this method will enable you to mould & cast multiple parts at the same time.

With a little practise you will soon know enough to make reasonable quality patterns that create good sand moulds.

There is one important pattern making tool that will make you wince when you purchase, but it is an important tool to have if you want to make accurate patterns where shrinkage rates are concerned.

The tool is the "Pattern Makers Rule", this is a ruler about 500mm (20")long. Made by Rabone Of England. No B5. And the graduations are marked as: 1/30-1/40-1/60-1/80,

The graduations represent the amount of shrinkage allowance for different types of metals. The pattern makers ruler provides a built in shrinkage percentage, which means you don't have to calculate the final measurement or size of your pattern, you simply take your measurement from your shrink rule, and transfer the measurement to the pattern being made.

The system is quite clever in the way it's all been calculated.

For a quick example, the 1/30 scale measurement seems to give

the correct result with patterns used for cast aluminium items.

Machining allowance on specific parts of a given pattern may also need to be considered, generally your own judgement can be used to judge that.

Pattern making can be quite a challenge for the hobby foundry worker, but once you learn the basics and develop your skills, with a little practice your patterns will get better and so will the overall casting quality.

If you intend on making lots of patterns, the investment in a shrink rule is well worth the money.

And while you're at it buy a good book on pattern making, it deserves a study all on it's own, but it forms an integral part of foundry work, and because you're the boss of your own workshop, you have to learn to wear the hat of the pattern maker & that of the sand moulder & founder.

Sounds like a whole lot of work doesn't it, but you'll soon learn what will work best for you. Spend the time to learn all you can, and you'll be rewarded with encouraging results.