According to the info below, since your EMT connector presumably comes with a locknut, you would need to use that first under this bushing, as the bushing can not be used as the means to secure the tubing to the enclosure.

Normally, since Rigid/IMC are threaded and EMT is not, fittings are labeled for one or the other. In this case, a Rigid/IMC grounding bushing should also be suitable for use with a threaded EMT connector (an "other threaded fitting"), as although the bushing seems to be straight threaded, not tapered, it has a set screw. My understanding is that without a locknut, set screw or other securing device, at least one of the two joined threaded pieces needs to have tapered threading in order to make the connection mechanically secure.

A useful summary of info on threaded Rigid, IMC and EMT fittings and connection from the Steel Tube Institute:

Fittings for Use with RMC, IMC and EMT

Threaded fittings

Threaded joints, both fitting to conduit and fitting to threaded integral box entries, shall be made up wrench tight.

NOTE: Avoid excessive force. Generally a force equivalent to hand tight plus one full turn with an appropriate tool is recommended. This should ensure engagement of at least three full threads.

Conduit bodies generally have an integral bushing to provide a smooth surface for conductors when pulled. This bushing is often mistaken for a conduit end stop. It is not necessary that the conduit be inserted flush against this bushing to assure a secure joint.

Properly align the raceway, fittings and knockouts to provide secure mechanical and electrical connections. Allow sufficient conduit length to complete engagement of the conduit and fittings at joints and entries.

Conduit bushings shall not be used to secure threaded RMC or IMC to a box or enclosure. A locknut shall always be assembled between a conduit bushing and the inside of the box or enclosure.

EMT connectors are permitted to be assembled into threaded entries of boxes, conduit bodies or internally threaded fittings having tapered threads (NPT). EMT fittings designed to NEMA FB 1, “Fittings, Cast Metal Boxes, and Conduit Bodies for Conduit and Cable Assemblies,” have straight threads (NPS). Threaded openings where these fittings are intended to be used are permitted to have either tapered (NPT) or straight (NPS) threads. Care should be taken to ensure that the threaded entry will accommodate a minimum of three full engaged threads of the fitting.

Where a locknut is provided with a fitting as the means of securement to a box or enclosure, the locknut is to be secured by hand-tightening to the enclosure plus 1/4 turn using an appropriate tool.

NOTE: While securing the locknut, take care to avoid excessive pressure when gripping the body of the fitting is necessary.

Do not rely upon locknuts to penetrate nonconductive coatings on enclosures. Coatings shall be removed in the locknut contact area prior to raceway assembly to ensure that a continuous ground path is achieved. Touch up bare area as needed after installation.

According to the info below, since your EMT connector presumably comes with a locknut, you would need to use that first under this bushing, as the bushing can not be used as the means to secure the tubing to the enclosure.

Normally, since Rigid/IMC are threaded and EMT is not, fittings are labeled for one or the other. In this case, a Rigid/IMC grounding bushing should also be suitable for use with a threaded EMT connector (an "other threaded fitting"), as although the bushing seems to be straight threaded (see drawing below of similar bushing) and not tapered, it has a set screw. My understanding is that without a locknut, set screw or other securing device, at least one of the two joined threaded pieces needs to have tapered threading in order to make the connection mechanically secure. EMT fittings (according to info below) are normally straight threaded

A useful summary of info on threaded Rigid, IMC and EMT fittings and connection from the Steel Tube Institute:

Fittings for Use with RMC, IMC and EMT

Threaded fittings

Threaded joints, both fitting to conduit and fitting to threaded integral box entries, shall be made up wrench tight.

NOTE: Avoid excessive force. Generally a force equivalent to hand tight plus one full turn with an appropriate tool is recommended. This should ensure engagement of at least three full threads.

Conduit bodies generally have an integral bushing to provide a smooth surface for conductors when pulled. This bushing is often mistaken for a conduit end stop. It is not necessary that the conduit be inserted flush against this bushing to assure a secure joint.

Properly align the raceway, fittings and knockouts to provide secure mechanical and electrical connections. Allow sufficient conduit length to complete engagement of the conduit and fittings at joints and entries.

Conduit bushings shall not be used to secure threaded RMC or IMC to a box or enclosure. A locknut shall always be assembled between a conduit bushing and the inside of the box or enclosure.

EMT connectors are permitted to be assembled into threaded entries of boxes, conduit bodies or internally threaded fittings having tapered threads (NPT). EMT fittings designed to NEMA FB 1, “Fittings, Cast Metal Boxes, and Conduit Bodies for Conduit and Cable Assemblies,” have straight threads (NPS). Threaded openings where these fittings are intended to be used are permitted to have either tapered (NPT) or straight (NPS) threads. Care should be taken to ensure that the threaded entry will accommodate a minimum of three full engaged threads of the fitting.

Where a locknut is provided with a fitting as the means of securement to a box or enclosure, the locknut is to be secured by hand-tightening to the enclosure plus 1/4 turn using an appropriate tool.

NOTE: While securing the locknut, take care to avoid excessive pressure when gripping the body of the fitting is necessary.

Do not rely upon locknuts to penetrate nonconductive coatings on enclosures. Coatings shall be removed in the locknut contact area prior to raceway assembly to ensure that a continuous ground path is achieved. Touch up bare area as needed after installation.

Sample grounding bushing specs (note straight threading):

A useful summary of info on threaded Rigid, IMC and EMT fittings and connection from the Steel Tube Institute:

Fittings for Use with RMC, IMC and EMT

Threaded fittings

Threaded joints, both fitting to conduit and fitting to threaded integral box entries, shall be made up wrench tight.

NOTE: Avoid excessive force. Generally a force equivalent to hand tight plus one full turn with an appropriate tool is recommended. This should ensure engagement of at least three full threads.

Conduit bodies generally have an integral bushing to provide a smooth surface for conductors when pulled. This bushing is often mistaken for a conduit end stop. It is not necessary that the conduit be inserted flush against this bushing to assure a secure joint.

Properly align the raceway, fittings and knockouts to provide secure mechanical and electrical connections. Allow sufficient conduit length to complete engagement of the conduit and fittings at joints and entries.

Conduit bushings shall not be used to secure threaded RMC or IMC to a box or enclosure. A locknut shall always be assembled between a conduit bushing and the inside of the box or enclosure.

EMT connectors are permitted to be assembled into threaded entries of boxes, conduit bodies or internally threaded fittings having tapered threads (NPT). EMT fittings designed to NEMA FB 1, “Fittings, Cast Metal Boxes, and Conduit Bodies for Conduit and Cable Assemblies,” have straight threads (NPS). Threaded openings where these fittings are intended to be used are permitted to have either tapered (NPT) or straight (NPS) threads. Care should be taken to ensure that the threaded entry will accommodate a minimum of three full engaged threads of the fitting.

Where a locknut is provided with a fitting as the means of securement to a box or enclosure, the locknut is to be secured by hand-tightening to the enclosure plus 1/4 turn using an appropriate tool.

NOTE: While securing the locknut, take care to avoid excessive pressure when gripping the body of the fitting is necessary.

Do not rely upon locknuts to penetrate nonconductive coatings on enclosures. Coatings shall be removed in the locknut contact area prior to raceway assembly to ensure that a continuous ground path is achieved. Touch up bare area as needed after installation.

According to the info below, since your EMT connector presumably comes with a locknut, you would need to use that first under this bushing, as the bushing can not be used as the means to secure the tubing to the enclosure.

Normally, since Rigid/IMC are threaded and EMT is not, fittings are labeled for one or the other. In this case, a Rigid/IMC grounding bushing should also be suitable for use with a threaded EMT connector (an "other threaded fitting"), as although the bushing seems to be straight threaded, not tapered, it has a set screw. My understanding is that without a locknut, set screw or other securing device, at least one of the two joined threaded pieces needs to have tapered threading in order to make the connection mechanically secure.

A useful summary of info on threaded Rigid, IMC and EMT fittings and connection from the Steel Tube Institute:

Fittings for Use with RMC, IMC and EMT

Threaded fittings

Threaded joints, both fitting to conduit and fitting to threaded integral box entries, shall be made up wrench tight.

NOTE: Avoid excessive force. Generally a force equivalent to hand tight plus one full turn with an appropriate tool is recommended. This should ensure engagement of at least three full threads.

Conduit bodies generally have an integral bushing to provide a smooth surface for conductors when pulled. This bushing is often mistaken for a conduit end stop. It is not necessary that the conduit be inserted flush against this bushing to assure a secure joint.

Properly align the raceway, fittings and knockouts to provide secure mechanical and electrical connections. Allow sufficient conduit length to complete engagement of the conduit and fittings at joints and entries.

Conduit bushings shall not be used to secure threaded RMC or IMC to a box or enclosure. A locknut shall always be assembled between a conduit bushing and the inside of the box or enclosure.

EMT connectors are permitted to be assembled into threaded entries of boxes, conduit bodies or internally threaded fittings having tapered threads (NPT). EMT fittings designed to NEMA FB 1, “Fittings, Cast Metal Boxes, and Conduit Bodies for Conduit and Cable Assemblies,” have straight threads (NPS). Threaded openings where these fittings are intended to be used are permitted to have either tapered (NPT) or straight (NPS) threads. Care should be taken to ensure that the threaded entry will accommodate a minimum of three full engaged threads of the fitting.

Where a locknut is provided with a fitting as the means of securement to a box or enclosure, the locknut is to be secured by hand-tightening to the enclosure plus 1/4 turn using an appropriate tool.

NOTE: While securing the locknut, take care to avoid excessive pressure when gripping the body of the fitting is necessary.

Do not rely upon locknuts to penetrate nonconductive coatings on enclosures. Coatings shall be removed in the locknut contact area prior to raceway assembly to ensure that a continuous ground path is achieved. Touch up bare area as needed after installation.