Review By Dean Bielanowski  Timbecon Website - http://www.timbecon.com.au


Sherwood SCA-900 Lathe Copy Attachment

Review

By Dean Bielanowski

There are times when you need to build a table, a hall stand, repair or replace a leg, make some birthday or xmas gifts, or make multiple copies of an item on a lathe. While you can just make multiple copies by hand, the process can be time consuming, and unless you are an expert woodturner, chances are that all copies will not be exactly identical. This is where a lathe copy attachment comes into play. Some may call it 'taking the easy way out', but I think they have a place in woodworking, and they can certainly be time, and frustration-saving devices. On the menu today is the Sherwood SCA-900 Lathe Copying Attachment... I think we will indulge ourselves in a review!

Out of the Box
The first question that should be raised, even before you think about buying this is; "Will it fit my lathe?" In most cases, the answer will be yes. The SCA-900 is designed to fit any cast bed or twin bar lathe with a center height of 125-300mm (around 5-12 inches). I have an MC-900 wood lathe with a cast iron bed, and the lathe copy attachment fits this model just fine without any major modification.

The SCA-900 ships somewhat unassembled, so some assembly is required before you can attach it to your lathe. The instructions are not the best I have seen, but you can get by ok if you take your time, don't try to rush, lay out all the parts and screws/nuts etc before you begin and take it one step at a time. It took me roughly thirty minutes to put it all together, and another 5 minutes or so to attach it to my lathe. If you have a second person on hand to help, it makes the task easier. I got by fine on my own. The copy attachment itself is not overly heavy, but can be a little awkward to hold while securing it down.

Once it is installed on the lathe you can get a better understanding of how everything works, and you should play around with the adjustment features so you become familiar with the device before you start attacking those rare wood blanks. Essentially, the copying attachment will allow you to make copies of spindle type pieces. This includes everything from turned table legs to baseball bats! Naturally, this attachment cannot duplicate the inside of bowls, turned boxes etc.

You can also make up your own templates from thin sheet material like MDF or ply if you wish and use those.

How it works
You mount either your original turned piece to be copied, a sample piece you wish to copy, or your pre-made profile template into the lower section of the lathe. Adjustable stationary centers hold turned items securely on both ends, or small template pattern clamps hold your template underneath (there are three provided and they can be located at various intervals along the lower copy attachment frame).

A guide rod sits underneath the main carriage assembly and this rides against the edge of the template, or against your original turning. I guess its more accurate to say that it actually stops the cutter above cutting in too far or presets the depth stop point for any part of the template or turned object along its length. Any movement in this bottom guide rod effects an equal movement at the cutter tip above, so as you make successively deeper passes and slowly move the guide rod in closer to the template or sample turned piece, the cutter above cuts successively deeper as well. The bottom guide rod has a spring loaded attachment to the main carriage, so it can ride around curves and into coves to make a quality reproduction. Speaking of the cutter tip, this is located on the upper guide carriage, and is essentially a sharp-tipped diamond shaped 'chisel'. Some other branded models may ship with the standard hardened steel tip, however, the Sherwood model ships with the upgraded tungsten carbide cutter for added durability and longer cutting life. This comes at no extra cost to the purchaser, which is certainly a welcome, and free addition! The cutter tip is reversible, so you can use both ends as well.

So on a new copy procedure, you set your guide rod up on the outermost section of the template or copy piece (i.e. the widest part), lock the depth there and turn the wheel on the carriage to move it along its rail left or right. I found it is much easier to use the SCA900 when you rough turn your blank down to round to begin with. Furthermore, if you turn it down round to the diameter of the widest point of the original, or the pattern, you will make your task even easier. This results in a properly balanced blank, and there is far less vibration in the lathe and tool in use than when trying to turn down a square blank to round (trust me, I tried both!). Also, ensure the cutter tip is retracted back as far as possible once set to the widest diameter on the template so you have plenty of forward cutter movement range to work with.

As the carriage and cutter tip move, it 'turns' off a shallow layer of material. It can give a rough result, depending on the wood used. Pine and other softwoods tend to chip out quite badly, so its a good idea to make relief cuts on any square edges of a turning to avoid this problem. Once you reach the end of the rail, set it a little deeper and start winding the carriage back in the opposite direction, and hence, taking more material off the blank. Depending on your template or the complexity of the turned piece, you may need to turn your item in sections, or work the widest diameter sections as a group before turning down to the thinner sections. You continue this process, and work your way around the various coves, tapers and beads etc in the piece. The spring loaded guide rod underneath guides the cutter around profiles as you go. It's a good idea not to take off too much material in one pass. That will prematurely blunt the cutter tip and results in a rougher finish. There is a hand steady handle that can directly control the depth of the TCT cutter up top, and this is useful if you need to plunge the cutter into a section before guiding with the hand wheel laterally. This guide handle can also be set to stop at a set depth via the cut depth adjustment wheel it is attached too. Additionally, I found using the handle allows more controlled turning, especially around tighter profiles.

There are metal 'sleeves' around the guide rod underneath which help it to roll over the template, however, for finer work, these sleeves are a little thick. They can be removed easily to leave you with a thinner rod to get into tighter places, however, this thinner rod (which is actually the underlying screw - non-threaded shaft) is a little harder to roll around curves and across surfaces, so more care is required by the user.  

The whole process can take a good length of time the first few times you use the attachment. It may well take several hours to turn out 4 or so legs for a table, so its not a production device that is going to give you results within minutes, although it really depends largely on the size/diameter of the blank, and how much material you need to remove from it. Patience is required, with the end result being perfect duplicate legs, or whatever other item it is that you are turning, and certainly better reproductions than you could do by hand, well with me at least. I'm not the world's best turner, so being able to duplicate a set of turned items is extremely useful in creating furniture or items that actually looks symmetrical! While you lose that added 'handcrafted' touch when you use such a device as a copy attachment, you have still put in the effort and hard work to make the original (if that is the case) and the copies, and no one can take that away from you. I found the satisfaction factor to remain very high in use. You certainly still end up with the same amount of mess on the floor as you do when hand turning.

Once your item is turned down, you need to sand it down to a smooth surface. I used 120 grit to start off, then 240 grit and finished with 320. Depending on the item, I sometimes sanded to a finer grade to give the surface finish desired.

Adjustment Features
The SCA-900 itself is adjustable to suit many types of lathes, and can be adjusted to handle different sized projects. For example, you can adjust the height of the cutter tip via the adjustable height pillars on both ends of the lathe, effectively raising (or lowering) the height of the entire copy attachment. This is achieved via basic clamp-type screw knobs. To be honest, it's not the world's easiest height changing design, and it can be a little tricky to adjust at times, however, you only need to set it once for each particular task, and that point is roughly at the midpoint of the blank's height/diameter.

You will also need to set up the width between the 'center' posts if you are copying an existing turning. I got caught out on my first attempt by not providing enough clearance either end for the carriage to travel right to the ends of my blank. The centers and end posts can be adjusted with a little screw work. A 3/8" spanner will do the job. Depending on your lathe, and the length of the project, you may also have to adjust the clamps holding the copy attachment to the lathe itself. I have a generic MC900 lathe, and I found I needed to add about 5 washers to each clamp under the base to ensure the clamp heads actually made contact with the bottom of the lathe bed to clamp it securely. No major drama.

Practice Makes Perfect
Familiarizing yourself with the SCA900 copy attachment before you turn expensive wood is recommended. The attachment itself is not overly complicated to operate, in fact, it is extremely easy, however, if you understand the basic principles of how it works, and what adjustment features give direct control over the cutter tip, you will minimize any 'first use' errors. I found that after I successfully completed my first copy of a leg, I had learnt all I needed to know to master this machine, it's that simple. My wife now uses it with equal success as well.

I found that on some more intricate patterns, you may need to finish off the finer sections with a little hand turning work because the guide rod just couldn't get into those small grooves effectively. This is not really a problem in my opinion. I'd rather be left with that small task (which was mostly small flat sections finish with a parting tool) than trying to mark out and duplicate 6 legs to close tolerances from scratch by hand! Also, because the cutter is essentially just a sharp tip, a bit of finishing sanding work is required to smooth everything out. Again, a task I am happy to complete knowing I have just turned exact duplicates very easily. A skilled turner could probably certainly turn down 4 legs faster than I could do it with the SCA-900 copy attachment. I'm no expert woodturner, but with the SCA-900 you could easily be tricked into thinking I was! It seemingly gives you the skills of an experienced woodturner, even if you have no woodturning experience at all.

Conclusion
The SCA-900 will not mass produce turnings in record times. It can take a few hours to turn out a set of table legs (depends on diameter of course), however, if you are not an expert turner, or have never even turned before, you can make exact copies of those table legs, bed or furniture spindles, some pen styles, even baseball bats with relative ease. The other big advantage of the SCA-900 and similar copy attachments is that they can replicate custom pieces that are not readily available in hardware or woodworking stores. Consider a table with turned legs where one leg needs to be replaced. Chances are you cannot buy a replacement leg from anywhere locally, or even at all, however, with a lathe and the SCA-900, you can make your very own replacement, probably at a much cheaper price than it would cost to have a woodworker or woodworking shop create the custom item for you. The SCA-900 is also great fun to use. I'm certainly planning to now add more decorative and functional turned items to my future woodworking projects, as well as to turn out a couple baseball bats for my son and other young lads in the extended family for Christmas and birthday presents.

The Sherwood SCA-900 retails for just AUD$159... Yes, you read right. At well under $200, the copy attachment is almost a steal and certainly worth the money considering how much you can save on buying pre-turned or custom turnings from a retailer. I was quite happy with the performance of the SCA-900. While some adjustments take a little 'work', on the whole, the copy attachment performed its intended task extremely well, and in the end, that is what counts the most to me!

The Sherwood SCA-900 is sold by Timbecon in Western Australia. It can be ordered via their website at www.timbecon.com.au or by phone (phone number available on their website).

Note that similar copy attachments/duplicators are available around the world and made/sold by various manufacturers (for our USA/Canadian and International readers).

You can order this item online in Australia from:

 

SCA-900 Photos
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The SCA-900 assembled and fitted to the lathe.


The hand wheel moves the carriage along the rail left and right.


The diamond shaped TCT cutter comes standard on the SCA-900!


Template clamps


Note the black 'centre' in the middle of picture to clamp existing turned items securely.


The clamps holding the copy attachment to the lathe bed.


The guide rod extends down beneath the main carriage.


Ready to copy! The original mounted below, the blank loaded up top.


Making a copy. Note some of the lower leg profile is already starting to take shape on the top blank.


And here's our copied piece...


The original, and the copy (after sanding). I had to hand-finish the finer details, but otherwise, pretty much a perfect match!

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Reproduction in any form prohibited with express prior written permission. Copyright 2004