Hub adaptors do NOT allow the use of 10.5" reels on machines were not designed for them. A simple test: are the reel tables on your machine less than 3" in diameter, or the reel table spindles less than  10.5" apart? If yes, it cannot handle 10.5" reels (they physically wouldn't fit...). Another test: does the distance between the reel spindles and  the nearest fixed object (on either machine shown below, this would be the upper corners of the head block cover with the Teac nameplate) measure less than 5.5"? If yes, there's insufficient clearance for 10.5" reels. Another clue: virtually all 10.5" machines have a tape size selector switch (usually marked large/small, 10/7, or similarly) used to adjust fast-wind speed and torque; if your machine lacks this feature, it's likely made to handle 7" reels only. Incidentally, neglecting to set this switch properly can cause severe tape stretching and tape spillage or breakage when transitioning from fast forward or rewind to stop; don't ignore it!

Above is a Teac A-3300SX with 10.5" reels mounted using our hubs. Note the location of the reel tables way out in the far upper corners of the front panel; this is typical of most 10.5" machines and is necessary to provide clearance for the reels. The size selector switch is right next to the speed selector, under the left reel. This switch controls fast wind speed, torque and braking balance.	Above is a Teac A-2300SX; this 7" model's reel tables are more centered, making for a much shorter machine. The 7" reels shown  barely clear the head block; there simply is no room for larger reels. Note also that there are only two switches under the left reel (compared to the A-3300SX's three); there is no tape size selector switch.

Metal NAB reels are quite a bit thinner than plastic ones, and sometimes require spacer shims placed between the reel table and reel to to properly align the tape path and prevent rubbing against the edge of the reel. On Tandbergs and older Akais as well as some Revoxes and Studers, the spindle lock doesn't tighten up enough to hold metal tape reels snugly against the reel table unless shims are used. This looseness can cause the reel to rattle against the hub when fast-winding. Placing a shim between the reel table and the metal reel increases the overall reel thickness, and dramatically improves the clamping force so that the reel will not move within the hub adaptor. We do not supply shims with our hubs or separately. The image above shows a manufactured Tascam shim, but you can easily make your own. UPDATE; we've recently discovered a VERY simple source of shims; old useless CDs. You can add paper stick-on CD-R labels to increase thickness incrementally if needed, but two standard audio CDs stacked on each table are the perfect thickness to center the tape path on our metal TDK reels. This snugs the reels up just fine on our Revox A77 (which has really wimpy spring-loaded reel retainers). Best way to use them; glue two CDs together with the label sides facing out;  we use garden variety household cement spread very thinly. Doing this keeps them paired and also provides better friction against the reels. Mini (3") data CDs work too, but only catch the very edge of the reel holes; we prefer the standard CDs for the larger surface area and greater friction they provide.

Very old reel-to-reels which use push-on or snap-on rubber reel holders such as the Sony ones shown above will not work with our NAB adaptors (and be advised; the much more expensive  TZ-612 Tascam/Teac variety sold elsewhere will not work either).  These machines  were originally designed to be operated lying on their backs, before vertical operation became the norm. Teac's type TZ-610 hub was intended to fit such machines; this product was discontinued over twenty years ago, and sadly we know of no source for anything similar. If you are successfully using rubber push-on reel holders with 7" reels, do NOT count on them to secure a much heavier 10.5" reel. A metal reel which falls off the machine while in rewind or fast forward becomes a VERY dangerous flying object. Use our hubs only on machines that actively secure the tape reels with twist type spring loaded or screw type retainers as described above. Older machines with weak reel spring type clamps (see commentary re this at left) are often easily repaired by stretching the original tensioning springs to re-energize them, or by replacing the springs with stronger ones.

Why choose our hub adaptors? Ours are practically indestructable; the TZ-612 variety has moving parts which rub and wear, and can fall apart with age or if overtightened. We always have ours in stock and we control their manufacture; sellers of those other hubs mostly obtain them as they sell them, do not control their supply and cannot guarantee long term availability. And the BEST reason: ours are less than half the price, and generally cost less to ship...

 
$24.50 per pair plus shipping