BlackAces
New User
I believe all of those Dunlops were made by Kunnan. The largest was worthy of the name
Black Max - what a beauty!
- Thread starter Grafil Injection
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serveandvolE
Rookie
It mentions that they have a built-in guard on the later generation Graphite Edges. To be honest, they really don't do a dang thing. I've been using the HGE since the 80s and the head grinds down quick. I have to put a double layer of tape on the head and change it out about every other hit.
vsbabolat
G.O.A.T.
He did make all of those Dunlop’sI believe all of those Dunlops were made by Kunnan. The largest was worthy of the name
Grafil Injection
Hall of Fame
Unfortunately, I can't find a BM Pro in decent condition to test. How much more stiff do you find it plays compared to BM? I have a vague recollection of people saying it was too stiff at the time, but that would be compared to various noodles.
Nerdy side question: do your BMs (non-Pro) all have an MM code on the side? I am guessing that stands for Midsize Metal as is written on the head-cover. Or did they move onto MG for Midsize Graphite, or something different?
DariaGT
Professional
[Although there are various BM threads already, I couldn't find any that the content was still live and the pictures still linked]
I have wanted a Black Max since I first saw the adverts in the early 80s, which made it look like a mean and classy stick. Although it came out in the late 70s, such adverts were produced for the original version ('Graphite/Glass' on hoop) as late as 1986, so it had a good run and it certainly was considered a high level offering, at least until the 200G came along.
{Black Max, MAX 200G Glossy, PS85 SV3, Wilson 80/20)
I use a Srixon CX tour but the old BMax is so much sweeter for OHBH due to its better balance and narrower throat.
Most racquets today have wide tapered throats that dont get with the OHBH takeback.
Grafil Injection
Hall of Fame
I concur, the balance and weight distribution is very amenable for the OHBH. I am also completely used to the squarish handle now after a couple of week's play.
serveandvolE
Rookie
I have a few BMPs in close to pristine condition and I coincidentally just strung one up yesterday replacing the original strings (tension dropped into the 30s) with some fresh synthetic gut (Head. Syn PPS @53lbs). I took it out for a hit and it felt really nice with what I considered a very generous sized sweetspot. I would say it's not too much stiffer than the BM and in general feels solid. Comparing the BMP to an average stiffness modern racket I would be considered it flexible. If I ever switch rackets from my Graphite Edge it would probably be to the BMP. I would just need to slightly modify the super squarish grip (same as the BM).
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Sanglier
Professional
I have one early bumperless "Black Max" with shared holes, one later bumpered "Black Max" with separate holes, and one "Black Max Pro". Their measured flex are 61 RA, 57 RA, and 58 RA, respectively. They weigh between 352g and 358g strung and have more or less the same swing weight (346-347). Granted this is more anecdotal evidence than meaningful statistics, but I honestly can't tell much difference between them in terms of demeanor and behavior.
The fact that these "Black Max" frames were lot/batch-numbered using transfer decals is quite extraordinary to me, considering their low retail price. A much cheaper and faster way to do this would have been to roll stamp the butt cap or grip collar, like other manufacturers were doing. I don't know the size of these batches, but I've only come across a single pair of racquets sharing the same number among the dozens I've observed.
Bumperless "Black Max" had batch numbers beginning with "00", "S", "M", or "MM". I suspect Dunlop might have relied on more than one contractor to make these racquets, as some of these frames came with a completely different butt cap. The "MM" ones are the most common; they began to be fitted with a bumper somewhere around "MM12100", though some bumperless frames can be found with a higher batch number than bumpered frames during the transition.
I have only seen "Black Max Pro" with batch numbers beginning with a "B". The aforementioned pair with the matching numbers were "Black Max Pro"s; which is consistent with the assumption that these were produced in smaller quantities (i.e., fewer batches) than the standard "Black Max".
serveandvolE
Rookie
My 2 out of the 3 Black Max Pros (weighed strung with overgrip and a layer of head tape put it on over the bumper- hard to find so might as well make those last as long as possible) 368g and 364g. The newest without overgrip and without tape is 355g. All of them start with "B".
serveandvolE
Rookie
Sanglier,
I've seen some Black Maxs with bumper guards. Did Dunlop actually produce them with bumper guards? If so, I'm guessing they were a later run of the racket.
Also, the hole location of the BM and BMP seems exactly the same. Am I correct to assume that the bumper guard for the BMP could fit on a BM?
Sanglier
Professional
Yes, as VS noted on the previous page, Dunlop was the first to put a bumper on their tennis racquets (though the idea itself had already been patented in the 1930s, so it was no longer patentable by itself, as everyone else quickly adopted this rather obvious improvement during the subsequent product cycles), and "Black Max" was one of the first Dunlop products to be updated with this feature.
The bumper and grommet strip on the "Pro" are identical to those on the bumpered "Black Max", so they should be interchangeable. The only external difference between my BMP and bumpered BM, other than the cosmetics, is that the grip on my BMP is 1/3" shorter than that of my bumpered BM.
Grafil Injection
Hall of Fame
Great info! Mine's MM I I 0786. It's bumperless with grommet strip and no shared holes. Weight was 360g strung with the original leather, now 352g with just two OGs. Seems like quite a consistent weight range with those mentioned above. Similar weight to an RF97A in fact, but I'd say a bit easier to play with.
Don't Let It Bounce
Hall of Fame
I picked up a Black Max at a thrift shop a few years back: 357 g, no bumper, no shared holes, serial MM 2277, nylon strings better suited for a weed eater, and the original Dunlop "Premium Quality Cowhide" grip. (Dunlop made 'em from the plastic cows that roamed 1980s America, their premium quality hides treated with WD-40 and bakelite). But, man, this thing hits with a lush, cushioned comfort matched only, for me, by other Kunnan Lo frames. I did not know until this thread that that's who made it, but I should have guessed from that wonderful feel.
True Tale: the BM (you know, if you're old enough to remember the Black Max, you're probably more likely to use that abbreviation when describing how the Metamucil's working for you) was actually the first larger-head frame I ever hit with. It was summer 1981, and I resolved to join the revolution and buy either a Yamaha YFG-65 (I had bad Yamaha lust; still do) or a Prince Pro. We couldn't get demos of just any frames we might have read about in Tennis magazine, so the closest as I could get was a Black Max and a Prince Classic.
I resolved to play a set with each . If I did better with the midsize BM, I'd buy the YFG-65. If I did better with the OS, I'd buy a Prince Pro. As it happened, I won both sets at 6-0, against a guy who played ahead of me on our high school team but who was still stuck with the primitive standard-size head! It wasn't even fair. That messed up my decision protocol, but I thought I felt slightly more invincible with the butterfly catcher... so I imprinted on the 80s Prince OS frames I've gone back to using now, in my dotage.
If only my teammate had held serve just once in that second set, I might have become like most of you in this thread: a real player, owning real graphite while still a junior, wielding the sleekness of midsize, and possibly even developing actual hand-eye coordination!
True Tale: the BM (you know, if you're old enough to remember the Black Max, you're probably more likely to use that abbreviation when describing how the Metamucil's working for you) was actually the first larger-head frame I ever hit with. It was summer 1981, and I resolved to join the revolution and buy either a Yamaha YFG-65 (I had bad Yamaha lust; still do) or a Prince Pro. We couldn't get demos of just any frames we might have read about in Tennis magazine, so the closest as I could get was a Black Max and a Prince Classic.
I resolved to play a set with each . If I did better with the midsize BM, I'd buy the YFG-65. If I did better with the OS, I'd buy a Prince Pro. As it happened, I won both sets at 6-0, against a guy who played ahead of me on our high school team but who was still stuck with the primitive standard-size head! It wasn't even fair. That messed up my decision protocol, but I thought I felt slightly more invincible with the butterfly catcher... so I imprinted on the 80s Prince OS frames I've gone back to using now, in my dotage.
If only my teammate had held serve just once in that second set, I might have become like most of you in this thread: a real player, owning real graphite while still a junior, wielding the sleekness of midsize, and possibly even developing actual hand-eye coordination!
michael valek
Hall of Fame
Never had one, but I think there was also a white max which was the same as the slazenger ceramic which connors used( I did have two of those)
michael valek
Hall of Fame
Gerade bei #eBayKleinanzeigen gefunden. Wie findest du das?
https://www.****-kleinanzeigen.de/s...buttons&utm_medium=social&utm_content=app_ios
michael valek
Hall of Fame
And a silver max
Grafil Injection
Hall of Fame
Something about mid-size frames is just, biomechanically, right.
vsbabolat
G.O.A.T.
These were made in West Germany by Erbacher. Very different from the Black Max made in Taiwan by Kunan Lo. My mom used the Silver Max back in the day and loved it. Also the Silver Max was one of the first premium racquets with a synthetic grip instead of leather.
kevin qmto
Hall of Fame
I’ve never seen or heard of anything but the black max. I just found another in a thrift store and nearly bought it but finally got control of myself lol. I already have one. I don’t need another.
Grafil Injection
Hall of Fame
Seems like a very robust frame (touch-wood) compared to other contemporaneous sticks, so one is probably enough for another 40 years!
Sanglier
Professional
A quick follow-up to my post #59 above.
I can now confirm that Dunlop did in fact engage multiple Taiwanese contractors to make the Black Max. Other than Kunnan, who actually made these using a 50/50 graphite fiberglass layup to satisfy Dunlop's cost-cutting requirement, different from the 80/20 ratio claimed by Dunlop's own marketing literature, some of the earlier frames were concurrently sourced from SanHoSun (which was to become Wilson's main supplier years later). Not only that, unlike Kunnan, SanHoSun manufactured theirs using a braided sleeve layup rather than plies of unidirectional prepregs, so they were completely different from Kunnan's Black Max under the skin, and more similar to Spalding's GC-20, which they also produced. However, because these early braided sleeves were not made using resin pre-coated filaments, they had to be dipped in liquified resin first before being used to make the racquets. Getting the resin formulation and coating right was the most technically challenging aspect of the manufacturing process (and treated as a trade secret by some of these Taiwanese contractors). SanHoSun's prowess in this area was not quite ready for the big leagues yet at the time, resulting in a high rate of QC failure, so their Black Max was likely not as resilient as Kunnan's, despite the fact that one of the key advantages of a braided layup over a unidirectional equivalent is the lack of weak spots.
I am not certain how to visually differentiate these SanHoSun frames from Kunnan frames short of giving them a severe head-rash. Based on my preliminary survey, I don't believe the batch number prefix is a reliable indicator for this. However, my gut tells me the frames with a raised-edge butt cap are SanHoSun products, while those with a round depression in the center came from Kunnan. The latter outnumber the former by ... a lot.
I can now confirm that Dunlop did in fact engage multiple Taiwanese contractors to make the Black Max. Other than Kunnan, who actually made these using a 50/50 graphite fiberglass layup to satisfy Dunlop's cost-cutting requirement, different from the 80/20 ratio claimed by Dunlop's own marketing literature, some of the earlier frames were concurrently sourced from SanHoSun (which was to become Wilson's main supplier years later). Not only that, unlike Kunnan, SanHoSun manufactured theirs using a braided sleeve layup rather than plies of unidirectional prepregs, so they were completely different from Kunnan's Black Max under the skin, and more similar to Spalding's GC-20, which they also produced. However, because these early braided sleeves were not made using resin pre-coated filaments, they had to be dipped in liquified resin first before being used to make the racquets. Getting the resin formulation and coating right was the most technically challenging aspect of the manufacturing process (and treated as a trade secret by some of these Taiwanese contractors). SanHoSun's prowess in this area was not quite ready for the big leagues yet at the time, resulting in a high rate of QC failure, so their Black Max was likely not as resilient as Kunnan's, despite the fact that one of the key advantages of a braided layup over a unidirectional equivalent is the lack of weak spots.
I am not certain how to visually differentiate these SanHoSun frames from Kunnan frames short of giving them a severe head-rash. Based on my preliminary survey, I don't believe the batch number prefix is a reliable indicator for this. However, my gut tells me the frames with a raised-edge butt cap are SanHoSun products, while those with a round depression in the center came from Kunnan. The latter outnumber the former by ... a lot.
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Grafil Injection
Hall of Fame
I believe I've seen different handle top pieces on the BM too, although all the ones in this thread have the large scalloped version, I think I've seen some BMs with a more normal smooth top piece.
I was interested in the comment 'SanHoSun manufactured theirs using a braided sleeve layup rather than plies of unidirectional prepregs', which suggests the whole frame is only braided. If you have a source for these details I would be grateful if you could find out more about that, because it offers a few possibilities:
1. A single thick braided sleeve with 50% graphite and 50% fibreglass (never heard of that).
2. Multiple thin braided sleeves on top of each other with 50% graphite and 50% fibreglass each.
3. Multiple separate braided sleeves of 100% graphite and 100% fibreglass on top of each other. (would be interested to know how the sleeves are put on top of each other).
There are three reasons I would like to know more about that:
i. Graphite and fibreglass tows are quite different in longitudinal strength, so I'd like to know if braiding them together is actually possible. There are plenty of separate graphite and fibreglass braids available, but I've never seen a product with them combined in a braid.
ii. 99.999% of the pretty graphite we see on the surface of products is woven graphite, but many people, even manufacturers, incorrectly call them braided. Often-time these are spread-tow woven graphite, in which each tow is flattened before weaving to emphasise the criss-cross pattern, and such spread-tow is typically dry and needs to separately doped as you mention. I wonder if SHS actually meant woven rather than braided. And there are plenty of woven graphite/glass products.
iii. We know that in one racket that definitely did have a real braided layer, it was combined with normal unidirectional graphite layers as well. The PS85 80-20 graphite-kevlar is comprised of a single layer of 50-50 braided mix, and a few layers of unidirectional graphite.
Hence, I wonder if the SHS product was really comprised of only braided layers, or if it was a product with a single braided layer and a few woven layers as well, which would have similar surface appearances.
Anyway, mine is a Kuhnan Lo with the depressed centre end-cap, which I agree I think most are. The reason for the slightly more solid feeling than most Taiwan models could be the 16mm beam, rather than 17.5mm that most others were. Black Max was positioned at the top of Dunlop's non-wood range, at least until they were sure the IMF process worked. There are adverts around 1980 with it priced around £60 when MAXPly Fort was £45, and when 200G came out it was just slightly more at £70.
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Grafil Injection
Hall of Fame
Braiding requires the tows to come into the product at 3-D angles to each other, rather than in the same plain as in weaving. And the braiding function needs to change the input tow on each turn. This means the machine needs a lot of room around it and tension is required as there is no flat bed that the product is lying on as in weaving. I'm sure it can be done with graphite and fibreglass, but like I said I have not seen a product for sale, nor any evidence it has actually been done in a racket. Whereas, there are plenty of braided graphite and kevlar products since they have similar strengths, and 100% braided fibreglass products (which are very soft tubes). Do you have any examples of a product or racket where the graphite and fibreglass are definitely braided together?
You can buy braided hybrid sleeves at any composites supplier. All of these materials are "soft" in tow form.
Grafil Injection
Hall of Fame
Yes, but are they susceptible to resin infusion and baking into a solid product like a racket? Or are they just used cold for pipework shielding etc?
Grafil Injection
Hall of Fame
Ok, but that's where I started. It is theoretically possible for a graphite and fibreglass braided together to have been used in a racket, but I would like to find some definitive evidence that it was. Up to now I have just seen snippets of inaccurate information. For example, the Snauwaert adverts show rackets with multiple layers of graphite 'braids' and kevlar 'braids' separately. But it is highly likely that they are in fact woven pre-preg layers, as they are shown in the typically number of layers 7-9 that we see in traditional composite construction. And, whenever there is a braided layer revealed on the surface of a racket, it seems to always be either just a graphite braid, a meaningless painted transfer, or a spread-tow graphite surface braid. Unless I see a picture of fibreglass and graphite being braided together prior to racket construction, or the finished braided layer, or some documentation describing a combined braid, I don't think it's possible to be sure it was actually used in that way in a racket.
Grafil Injection
Hall of Fame
I know you can make large simple objects from it, but I'm still not sure we have any information to say if it would work / be optimal for a racket, per options 1 & 2 about the BM I offered above, since a racket has its specific dimensions and strength requirements. All the braided rackets I've seen that include fibreglass, use the glass in a separate normal layer, and it is just graphite, kevlar (or graphite-kevlar) that is braided.
Yes, I haven't seen any surface finish versions of graphite-glass braids either, so I'd need some sort of manufacturing picture or document to confirm, which I appreciate is not going to be readily available!
Wilson braids Graphite and Basalt. I think you're looking for a complexity that is not there.
Grafil Injection
Hall of Fame
In fact I'm trying to simplify as it would be very unique in 1980 for a company to have a racket that was braided graphite-glass with nothing else. Much more likely to be the usual normal glass and graphite layers plus a single graphite braid.
Basalt is closer in performance to graphite than glass is, so braiding those two in a racket is very understandable. However, we don't have any evidence that a graphite-glass braid was ever used in a racket, so assuming that it was is complicating things if anything.
Grafil Injection
Hall of Fame
My mind is still open to the concept of a graphite-glass combined braid being used in a racket, which is why I asked the question for details above. I'm hoping that someone with precise information may respond.
Nostradamus
Bionic Poster
i bought that max 200 G at the garage sale and its a great racket, but its super heavy[Although there are various BM threads already, I couldn't find any that the content was still live and the pictures still linked]
I have wanted a Black Max since I first saw the adverts in the early 80s, which made it look like a mean and classy stick. Although it came out in the late 70s, such adverts were produced for the original version ('Graphite/Glass' on hoop) as late as 1986, so it had a good run and it certainly was considered a high level offering, at least until the 200G came along.
{Black Max, MAX 200G Glossy, PS85 SV3, Wilson 80/20)
I believe the one I've finally picked up is a fairly early example because it says Midsize Metal on the cover, whereas, later versions say Graphite on the cover.
There is great similarity in the design with the later Wilson PS85: even though mine is a bit worn, the paintwork is simple and has a classy matt finish; the beam is actually 1mm thinner than the PS85 at 16mm (same as the PK Black Ace), giving an very solid feel in-hand. Even closer similarity is with the Wilson 80/20, but the moulds are definitely slightly different (BM is rounder). Dunlop (via Taiwan) used their 'Premium Calfskin Leather' grip, which is thicker than the leather used on the MAX 200G or MaxPly woods. It's a lovely piece or leather, but would be better as a belt than a grip. It's too thick and becomes shiny. Specs are right where you would imagine: L4 - 360g, 31.75cm (8pt) HL strung. I removed the leather grip as it was fraying, and to get it down to size 3 using a Dan Evans 2 overgrip treament. Hence, mine is now 352g, 32.25cm (6pt) HL, so still fairly manoeuvrable.
Hitting is very close in feel to various Taiwan 85s with 80/20 or 70/30 graphite/glass mix, so the flex should be in the mid to high 50s. Obviously, nowhere near the stiffness of a PS85, but there is also no flutter and the sweetspot still feels large like the Wilson 80/20 also does. Black Max is not a noodle! The 16x19 pattern has a 1.35cm2 average cell size, which is a tad tighter than a PS85 (1.4cm2), but still somewhat open.
The only issue I've found, which a Youtube reviewer also mentioned, is the grip shape is very square. Bevels 0 and 4 being too large, so I am tempted to sand a bit of PU from bevels 1, 3, 5 & 7. So far though, after one brief hit, I can see why this was popular in the early 80s and is still a fine hit today. Note that mine was L4; I don't know whether LM and M versions also existed.
What I was wondering was why it didn't cut through at the Pro level? Was it too 'new-fangled' to replace the woods, and then got overtaken by MAX 200G and PS85 etc? I suppose it also didn't have quite the control/feel of the woods either.
Grafil Injection
Hall of Fame
The Glossy Pro model? That's interesting, what weight? My two L4s are 364g and 360g strung, which are my lightest 200Gs. The latter was 368g, however, but I replaced the leather grip with two overgrips (works great).
Nostradamus
Bionic Poster
Strung, it was around 12.4 OZ. had leather grip on plus the wilson pro overgrip
Grafil Injection
Hall of Fame
That's extremely light! Equates to 330g unstrung. I've never seen that low before. It doesn't say 'MAX 200G L' on it does it?
Sanglier
Professional
The source for my post above is an interview given to a Taiwanese academic researcher by the head of SanHoSun in the early 2000s, in which he disclosed that his earlier products, including the Black Max, GC-20, and some unnamed Donnay models, all had a purely braided layup. He imported the braided sleeves from Japan, but did the resin "wetting" in-house, and this was where most of his difficulties came from. He was not able to satisfy Wilson't strict quality requirements through this process until he began making frames out of unidirectional prepregs; which was how he won the Sting Mid contract that began his long and fruitful relationship with Wilson. He went back to using braided sleeves some years later, but by then the sleeves were manufactured using pre-coated fibers, making the process much simpler, and the quality more consistent. Also, the later "braided" racquets tended to have a mix of braided sleeves and unidirectional plies in their layup, unlike his earliest products.
He didn't reveal whether the sleeves used to make the Black Max had any fiberglass in them, so I can't answer your specific questions. However, @Bambooman is correct that there is nothing uniquely difficult about weaving or braiding fiberglass to carbon fiber. The fibers used to make these fabrics are very thin. Before the material is saturated with resin and cured, it is quite flexible. Bear in mind that the fiber behaves as a reinforcer of the resin by holding the resin substrate together when subjected to tensional stress, while in return the resin behaves like a glue that holds all the fibers together in order to spread the physical load among them simultaneously (hence the name FRP - fiber-reinforced-plastic). The individual fibers in the tow are free to move about relative to each other before their marriage with the resin matrix, hence their relative flexibility. After all, the chopped fibers in your favorite 200G are virtually in powder form, with no rigidity whatsoever on their own, yet they are strong enough and long enough at the granular level to absorb the stress from the nylon matrix in which they are embedded, and keep the latter from falling apart during decades of repeated collision with a ball; which it certainly would have without the reinforcement. It's actually quite astonishing how big a difference a little bit of this stuff makes.
Here is an example of a hybrid braided sleeve.
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Nostradamus
Bionic Poster
NO, its the regular 200G. maybe it was 12.4 oz Unstrung. i didn't actually measure the weight after i strung it. lol
Grafil Injection
Hall of Fame
Thanks for confirming. Yes, as I said above I'm aware that it is theoretically possible, but usually in the 70s and 80s, when a braided construction was used an advert or description was provided to confirm the construction, especially if two different materials were used in the braid. As you say you don't have precise details, isn't it more likely in that case to be separate single-material braids since they are both even more readily available (and cheaper) materials.
If a company makes braided carbon and braided glass it's very likely that they could just swap one of their two feeds and make a hybrid.
The main issue with sleeving multiple braids over each other is wetting out the layers if they are not pre-preg or sliding them over each other if they are already saturated with resin.
A few patent descriptions mention the issues of resin distribution.
The main issue with sleeving multiple braids over each other is wetting out the layers if they are not pre-preg or sliding them over each other if they are already saturated with resin.
A few patent descriptions mention the issues of resin distribution.
Ombudsman
Rookie
How differently do the Kunnan Lo’s play vs the SanHoSun frames?
I just checked and my butt-cap has a raised bevel, so I’m one of the (un)lucky ones? I played with the Black Max as my first racquet in the early 80’s followed by the PS85 St Vincent, which I played until the Head MG Prestige Pro.
https://photos.app.goo.gl/TKQwPAiRWEaG6p167
I just checked and my butt-cap has a raised bevel, so I’m one of the (un)lucky ones? I played with the Black Max as my first racquet in the early 80’s followed by the PS85 St Vincent, which I played until the Head MG Prestige Pro.
https://photos.app.goo.gl/TKQwPAiRWEaG6p167
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Sanglier
Professional
Until I read the interview mentioned above, I had never come across any specific mention of SanHoSun being a contractor for the Black Max, even though I suspected it to be the case due to the number of variants in existence, and the well-known practice by large racquet vendors to engage multiple contractors to make the same racquet during that period, ostensibly as a risk-mitigation measure, but also to drive down the cost of the contracts and to keep it down.
The people at Dunlop must have done some comparison at the time to see how each of these racquets performed, but this is understandably not something they'd have shared with the public, because they naturally wanted to maintain the impression that all of their racquets were made to the exact same specifications by the same people under their direct supervision. Given the rather low opinion Western consumers typically held towards products made in the East (with Japan just beginning to escape that trap during the period), no fuss was made about any of this by Dunlop, and none was given by their customers. I would wager that today, not a single person outside of those who made the racquets (and those reading this thread) knew this difference existed, so it's highly unlikely that you'd find their comparison data anywhere. Even the differential appearance of these racquets is little more than an educated guess on my part, to be confirmed (or disproved) by someone willing to strip off the paint on a bunch of these to expose the layup underneath.
Given that the variant with the raised-edge butt cap is the least common of the known Black Max sub-types, and yours is special to you and has clearly survived the decades intact, I'd say you are one of the lucky ones for sure, regardless of whether or not it was made by SanHoSun!
Sanglier
Professional
Yes, I've posted a number of times in praise of this little machine, which is versatile, portable, has a tiny footprint, and doesn't cost an arm and a leg to own.
It measures stiffness in "kg/cm", a proper physical unit, not some arbitrary mystery unit that has no meaning outside of tennis. Given that most of us have been conditioned to associate racquet stiffness with RA numbers, Stringway provided a conversion table for the user to translate kg/cm readings into RA. This table is not very extensive, and the relationship between the two numbers is not linear, so it is necessary to fit these numbers to a polynomial curve to make the conversion more useful, and automatic. I added the reading I got from my Wilson "Profile" (19.71 kg/cm; 92 RA) to the table to increase the curve's accuracy in the upper reaches of the RA range. The best fitting curve I was able to generate using an online tool is this 5th degree equation: RA = -159.7395 + 76.68511*X - 11.59075*X^2 + 0.9463168*X^3 - 0.03958306*X^4 + 0.0006626032*X^5 ; where X = Stringlab 2 reading in "kg/cm" . This is what I have plugged into my spreadsheet to automatically generate the RA equivalent after recording the measurement from my Stringlab.
If you are asking whether my readings matched those found in publications, I'm afraid I don't have a definitive answer for you, because most of the racquets I've measured are too old to have official RA figures. Some of these models also exhibit a good deal of variation from one example to the next, making single readings somewhat meaningless. However, in the few instances where I had taken notice, my readings for some popular models were in the same ballpark as what others had reported; so my confidence in this machine's accuracy remains unwavering.
A few things to note in case you are contemplating buying the Stringlab: 1) It works well for modern frames with a relatively thick beam profile. For thinner-beamed frames, you will need to raise the fulcrum bar to measure their flex. I found that placing a couple of nuts under the "legs" of the bar would do the trick. 2) The stock fulcrum bar is wide enough to accommodate nearly all racquets, but in some rare instances, a 12" bar may be needed. 3) The distance markings for balance point measurement are slightly off on the example I received, necessitating corrections. Other than that, it's all good!
