Open-Reel Tape Splicing Block

A tape splicing block is an essential precision tool used to join or repair broken audio reel tapes. It securely holds two ends of magnetic tape in a precisely machined channel, allowing you to cleanly cut and join them using specialised adhesive splicing tape.

The Tape Splicing Block is manufactured to Industry Standards. Manufactured from high-grade 6082 aluminium alloy, the machined block is sand-blasted then anodised to harden the surface and to prevent corrosion and oxidisation. Aluminium Splicing blocks are chemically anodised to prevent the black aluminium oxide from damaging your precious open-reel magnetic tapes.

How a Splicing Block Works

Splicing blocks are designed to make repairs seamless, whether you are dealing with classic 1/4" studio tape or other widths. 

Guide Channels: The block features a precisely milled channel that perfectly matches the width of your tape, ensuring it stays perfectly aligned without slipping.
Cutting Grooves: Most standard blocks have two diagonal cuts (usually at \(45^{\circ }\) or \(60^{\circ }\)) and one vertical cut. The diagonal cuts are used for joining two pieces of tape, as the angle prevents an abrupt "click" sound when the splice passes over the tape recorder's playback head.
Securing Mechanism: Many blocks feature a raised edge or a clamping plate to lock the magnetic tape steady while you make the cut.

The Splicing Process

Overlap and Cut: Lay the two ends of the broken tape into the block so they slightly overlap.

Make the Cut: Use a demagnetised single-edge razor blade or a precision cutting gem media blade to cut through both layers of tape simultaneously across the diagonal groove.

Remove Scraps: Discard the two overlapping scrap ends. The tape ends will now be perfectly flush with each other.

Apply Splicing Tape: Place a small piece of specialised, adhesive splicing tape over the joint on the non-oxide (shiny) side of the reel tape.

Trim (If Necessary): Trim any overhanging edges so that the splicing tape is slightly narrower than the magnetic tape itself, preventing it from sticking to the recorder guides.

History of Splicing Block

Tape Editing: EdiTall by Joel Tall

In 1952, audio engineer Joel Tall designed a device to securely hold plastic recording tape so that accurate splices could be made. Tall’s splicing block features a concave groove running lengthwise along the block.

The top edges of the groove canted inward slightly and locked the tape in place. Cross-cut grooves at 90 and 45 degrees to the slot enhanced the accuracy of the cut. Tall received U.S. Patent number 2,599,667 for this invention which was manufactured by Precision Tech, Inc. of New York. This splicing block was used at CBS Studios in New York from 1952 until 1962.

Joel Tall with Ampex reel tape recorders, created the tape splicer Editall used around the world. Joel Tall was born on April 17, 1905 and passed away in December 1986. He was married to Leona B. Tall and was survived by one daughter, Benita J. Kaplan. Leona helped Joel Tall found The Tall Company in the 1950's. Benita Kaplan has generously donated some of Joel Tall's personal papers and photos to our Museum of Magnetic Sound Recording. In 1950 Joel Tall filed U.S. Patent #US 2599667 A for his Splicing Block, stating, "This invention relates to splicing blocks, such as are used in splicing film and sound recording tape, and specifically it refers to a block which is particularly suitable for editing sound recording tape."

Essential tool: Splicing Block for Open-Reel Tape - An excellent choice for users dealing with multiple tape sizes, accommodating 1-inch, 1/2-inch and 1/4-inch open reel-to-reel tape widths.