Quality considerations

Question 11 "How can I tell how well engineered a table is?"
Answer. A table is well engineered if it does its job simply and efficiently without developing any problems. One of the most common problems with portable massage tables is that they are rickety or squeak.
When people talk about strength, they are usually referring to the weight the table will support. Most portable tables will support a static load far in excess of the levels they are subjected to in normal use. Equally important is how rigid the table is when it is pushed longitudinally or laterally, and how rigid it will be a year or so from the purchase date. Flex is also an important consideration in some modalities, e.g. chiropractic.
Some of the other factors affecting the engineering quality of a table are listed below.
[Q11.2] Hinges and Stays. Look at the way the legs are attached to the table and the type of hinges and stays (on a fixed height table) that are used. Hinges need to be tight (stiff) to avoid squeaking, and the stays that hold the legs in place are a critical factor if the table is going to be opened and closed often. Cheap fixed height tables use what is commonly called a "card table" stay. This is a friction lock designed for card tables, and the use of them on portable massage tables is asking them to do a lot more work than they are designed to do. They will work loose after being opened and closed a good number of times. After a while the table will develop longitudinal movement, and squeaking and creaking will result. This will ultimately lead to the table needing repairs. Better quality tables are manufactured using heavy-duty friction stays, or with locking stays.
Hinges also vary considerably in quality. Many manufacturers use cheap, low quality imported hinges that are not very stiff, and quite often squeak from the day the table is purchased. These hinges can often be identified because they only have three sections joining them. The better quality, stiffer hinges, generally have four sections joining them and are made from heavier gauge steel. If hinges are fitted to a metal framed table they should always be fastened into receptor fittings, never directly in to the metal.

[Q11.3] Frame. Frames can be made from aluminium, timber or steel, with aluminium being the lightest, and steel the heaviest. If the frame is made from timber it should use a lightweight hardwood such as Pacific maple; not softwood such as pine, that is not as strong, and often comes with knots, which further reduces its strength. Timber frames should be both glued and fastened to the plinth so they can never work loose and squeak. Avoid frames that are attached solely with a nail gun for cheapness and convenience. Metal frames should be riveted, bolted or screwed to the plinth, and if made of steel it should be treated or powder-coated to reduce future problems with rust. Aluminium framed tables never suffer from rust problems.
[Q11.4] Plinth or frame base. The plinth is designed to increase the strength of some table frames and/or as a support for the foam in the upholstered top. Plywood is generally regarded as the best material for plinths on portable tables because of its strength and light weight. However there are many different types of ply, ranging from cheap and nasty, to very high quality marine grade. The thickness of the ply also impacts its suitability. The type that is used depends to a large extent on the type of frame. Steel and aluminium framed tables can use a variety of ply’s. The lightest tables use an aluminium frame with a very thin, high quality ply plinth fastened to the frame (either riveted, bolted or fastened with special screws). The suitability of the ply depends more on the way it is fastened to the frame than on the thickness or inherent strength of the ply. Timber framed tables rely more on the strength of the ply, and the better quality tables use at least 9.0 mm thick ply that is glued to the table frame. Lesser quality tables use 4.0-7.0 mm. The highest quality timber framed tables use structural grade ply that has been tested to A.S.A. standards. A plinth that has been properly glued on to a timber frame is permanently attached, and can never come loose or squeak.
Another indication of a better-engineered table that cannot be seen after the table is completed, is the finish on the edge of the ply. A manufacturer, who is concerned with more than the superficial appearance of his product, will round off the edge of the ply so there is no sharp edge to dig into the arms when they are hanging over the edges of the table. This is important even if the table has foam around the edge, because a sharp edge can eventually cut into the foam and reduce its effectiveness.
Some tables are manufactured with a material mesh plinth instead of a plywood plinth. Tables with a mesh plinth are not suitable for many types of modalities, especially deep tissue and remedial massage and certainly not chiropractic or osteopathic treatments. The mesh is stretched like a drum skin and does not offer the same stiffness and support as a plywood frame base.
Generally speaking frames with a mesh base are narrower (61cm) and shorter* (85cm) than standard table frames (66cm x 92cm) because of the smaller table dimensions they are light in weight but they are also a compromise in table size and suitable for only very light massage work. 
*Note these tables are often sold with a face cradle and the dimension of the table quoted includes the length of the face cradle
[Q11.5] Vinyl. Vinyls vary in quality and price by up to a 10 factor. Some cheaper vinyls on imported tables will have the colour wash out of them when they are cleaned and will not stand up to the rigors of professional use and Australian climatic conditions. Vinyls also vary in surface texture and pattern. Of particular importance is the guarantee on the vinyl. Look for 2 years minimum warranty on the vinyl of a quality table. Refer also to the answer to question 12 below. There are also some high quality imported vinyls available. These usually come from the U.S.A. or Italy, and are generally more expensive than the local vinyls although they may offer some special features not available with the local products, e.g. able to be cleaned with disinfectants, extra softness, etc.
[Q11.6] Foam. The quality of the foam used in a table is the critical ingredient in the comfort of your patient. It is important to understand a little about the types of foam used in treatment tables in order to make an informed choice.
[Q11.7] A. Foam quality. The quality and price of foam can vary enormously. The price difference can be as much as a factor of 4 or 5 from the lowest grade foams, to the highest. There are many different types of foam (over 30 grades) ranging from low density, through normal, standard, and high density grades, and from low resilient through to the very best high resilient (HR). The foam on some tables initially feels comfortable (as in some car seats) but after you have been on it for some time you find it does not give you adequate support. Cheaper foams also tend to sag prematurely and lose their shape. Look to the length of the manufacturer’s guarantee as the definitive guide to the quality of foam used. Foam with a long guarantee to keep its shape is obviously a better quality than foam with a short or no guarantee.
A quality table is an investment in comfort and appearance. Carefully check the "feel" of the foam by pushing your hand into it and also by lying on it. Cheaper foams "bottom-out" and have very little spring back. Better quality foam will spring back to its original shape. When gauging the quality of foam in a table be sure to lie on the table as well as feel it with your hand. This is because the pressure exerted by a body on a table is quite different to the pressure exerted by the hand. In fact the pressure exerted by the hand is much greater, and this can give a false impression of the comfort of the table if not followed up by actually lying on the table. Thicker quality high resilient foams will increase the weight of your table, so unless the table is very light weight to start off with, then these enhanced comfort features are best applied to tables where weight is not an issue, e.g. in a clinic situation where the table is unlikely to be carried around very much.
As an added bonus, high quality foams are manufactured without the use of ozone-depleting CFC’s, while many poorer quality foams are still manufactured with CFC’s. To be sure, you should ask the table manufacturer what type and grade of foam is used in the table.
[Q11.8] B. Foam thickness. A thinner cross section of better quality foam will actually provide more comfort, support and durability than a thicker cross section of poorer quality foam. From this it follows that the thickness of the foam padding by itself is not necessarily a good guide to the quality of the table. Some manufacturers use "profiled " foam that is shaped like the inside of an egg carton. This allows them to state they are using a thicker (but lighter) layer of foam, although durability will be less than a thinner layer of solid foam of the same grade.
[Q11.9] C. Foam layers. Foam layers can be very useful in achieving a plethora of working surfaces. Progressive changes of density can give enhanced comfort, softness and support. Extra layers can improve on the comfort of even the best single layer foams. Softer foams can be placed over firmer foams to achieve the desired cushioning.
Unfortunately multi layers of foam can also be used to cut costs. Some manufacturers use one or more layers of low cost "fillers" in their layered construction. Relatively good quality foam is used on the top layer to give a good "feel" to the table while the underlying layers are of poor quality.
Make sure to check the quality  and density of the layers of foam. A manufacturer who simply states that a table has many layers of foam gives the purchaser no indication of the comfort or quality of the foam. Foam durability is governed by the weakest link, so unless all the layers are of the same quality, such a multi layer foam table may not last as long, or give the same level of comfort, as another table with a single layer of higher quality foam. Again the overall warranty on the foam is a good guide to its quality.
D. Foam firmness. Different modalities have different foam requirements. Generally speaking the longer the treatment the more comfort is required. Sports and remedial massage therapists prefer a firmer working surface than say a practitioner in the relaxation field, where treatments can last an hour or more. Thicker, softer foams are best suited for these relaxation treatments. Chiropractors and osteopaths who perform adjustments and manipulations require very high-density foams - a very firm working surface (also popular with Alexander technique, and Feldenkrais practitioners). There are many other modalities with special requirements. A reputable manufacturer will supply a large range of foam types to suit individual practitioner needs.
    
 
[Q11.10] Upholstery. If you look carefully at the upholstery on a table it is usually fairly obvious if a professional upholsterer, or only a semi-skilled person has done it.
A quality table will have professionally finished upholstery work that is quite obvious in a table-by-table comparison with a lesser quality table. Look at the corners of the tabletop; examine the way the upholstery is done. Some tables have roughly folded corners that are simply pinned into position. These can easily snag, providing areas for dirt and grime to lodge, and are unattractive. Only a qualified upholsterer will be proficient enough to provide a professional looking finish to a table while the work of unskilled upholsters is usually fairly obvious even to the untrained eye.
[Q11.11] Adjustable Tables. There are some additional considerations that should be taken into account if the table has adjustable legs. An earlier question considered the range of height adjustments and their suitability for the practitioner. With adjustable height tables it is also important to look at the actual adjustment mechanism on each of the table legs to see how simple and positive it is to operate. Adjustable height tables normally have a different type of stay to fixed height tables, and this should also be checked for positive and simple operation as well as freedom from rattles.
Adjustable height tables normally have a steel tension cable that is the critical component in keeping the table erect. You should enquire about the breaking strain on the cable and also examine the swages used to fasten it to the table legs. The minimum breaking strain should be at least 500 kilograms. Because there are no centre legs on this type of table, the hinges joining the two halves of the table and how they are fitted are of critical importance; they should be extremely strong and well made. Also of importance is the degree of flex in the middle, and the overall stability. Finally check that the table does not rattle, particularly around the section where the leg extensions fit into the legs proper.
Another important factor to consider with adjustable height tables is the ease of erecting and dismantling. Generally speaking tables that have press button locking systems for the struts will tend to become noisier over time and also require an additional action to dismantle (pushing the button on the strut). Aluminium strutted tables with a single centre strut tend to have more sideways torque (or twisting motion) when weight is applied to the outer edge of a table as in deep tissue or chiropractic work.
Some adjustable height tables make up for their lack of real engineering by having very complex under carriage arrangements e.g. double strutted multi cable systems must always have a lower cross brace (to support the struts) and this often gets in the way of a practitioner’s knees.
The most elegant solution to this quandary is probably the design registered double triangular strut system. It is extremely strong and light (two triangles back to back), folds and erects without buttons, minimises the number of cables required, and yet still provides practitioner knee access when seated.