How do I shorten a coaxial output line?

2021-03-02

By Kevin

It may be necessary to cut or shorten coaxial hose to fit a specific machine or system placement. Doing so is not difficult, but it does require care in order to yield good results. It is possible to cut or shorten from either end of the hose (nozzle or pump end), but it may be easiest to work from the pump side of the coax.

If working on the pump side:

Begin by unscrewing the 3/8" push in fitting from the pump block.
Pull the outer 3/8" tube and push in fitting away from the pump block exposing the 1/8" nylon capillary tube.
Using a pair of needle nose pliers placed flush against the face of the pump block, grab the 1/8" nylon capilary and lever the pliers against the pump block to pull the capillary from the brass barb fitting in the pump (NOTE: do not use a razor blade or other cutting implement to cut the capillary along its axis to remove it from the barb fitting. Doing so can damage the barb fitting and result in system performnce issues. Also, do not grab onto the barb fitting with the pliers).
Remove the push in fitting from the 3/8” tube.
Squarely cut the 3/8” and 1/8” tubes to the appropriate length.
It may be necessary to trim the outer 3/8” tube back slightly so there is enough of the 1/8” nylon capillary that can be pulled out of the 3/8” tube to reconnect with the barb fitting on the pump. (TIP: to help pull the 1/8” nylon out from the 3/8” tube carefully insert a straight pick or appropriately sized drill bit (the non-fluted end) into the 1/8” nylon tube until the tool is lightly pressed into the tube. Next pull the tool out and the 1/8” nylon should come with it) If the 3/8” tube must be trimmed back then insert a tool onto the end of the 1/8” nylon tube to force it back into the 3/8” tube about an inch or so. While holding the 1/8” nylon tube back inside the 3/8” tube cut the 3/8” tube with a razor blade. Do not try to cut the 3/8” tube where the blade could also cut the 1/8” nylon tube or the nylon tube may accidentally get nicked resulting in system performance issues.
Reinstall the push in fitting onto the 3/8” tube.
Carefully install the 1/8” nylon tube onto the barb fitting on the pump. Ensure that it is fully installed onto the barb fitting. If the nylon tube is not fully installed onto the nylon barb then system performance issues may result.
Screw the push in fitting back into the pump block.

If working on the nozzle side:

Begin by unscrewing the nozzle from the nozzle coupler block and remove the nozzle capillary from the brass splicer in the nozzle coupler block.
Unscrew the 3/8” push in fitting from the nozzle coupler block and remove the nozzle coupler block.
Remove the push in fitting from the 3/8” tube.
Carefully remove the 1/8” nylon tube from the brass splicer. Damage to the barbs on the splicer may cause system operating issues. Use extreme care to prevent damage to the splicer.
Squarely cut the 3/8” and 1/8” tubes to the appropriate length.
It may be necessary to trim the outer 3/8” tube back slightly so there is enough of the 1/8” nylon capillary that can be pulled out of the 3/8” tube to reconnect with the brass splicer. (TIP: to help pull the 1/8” nylon out from the 3/8” tube carefully insert a straight pick or appropriately sized drill bit (the non-fluted end) into the 1/8” nylon tube until the tool is lightly pressed into the tube. Next pull the tool out and the 1/8” nylon should come with it) If the 3/8” tube must be trimmed back then insert a tool onto the end of the 1/8” nylon tube to force it back into the 3/8” tube about an inch or so. While holding the 1/8” nylon tube back inside the 3/8” tube cut the 3/8” tube with a razor blade. Do not try to cut the 3/8” tube where the blade could also cut the 1/8” nylon tube or the nylon tube may accidentally get nicked resulting in system performance issues.
Reinstall the push in fitting onto the 3/8” tube.
Install the 1/8” nylon tube onto the brass splicer. Ensure that it is fully installed onto the splicer.
Insert the splicer back into the nozzle coupler block and screw the push in fitting back into the pump block.
Install the 1/8” tube from the nozzle onto the other side of the splicer and fasten the nozzle to the nozzle coupler block.

See the two excellent related videos to help further explain the steps outlined above.