Tech Tips

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There are certain aspects of an automobile that don’t get much attention. Some concepts have stood the test of time and are as effective today as they were 50 years ago, but that doesn’t necessarily mean that tried-and-true methods can’t be improved upon. Case in point: Pi-Thon Hose Locks as an alternative to traditional hose clamps. The last time you gave any thought to your hose clamps was probably the last time you were cursing the factory-installed spring-type clamps while attempting to remove them with a pair of pliers. You probably replaced them with standard worm-drive hose clamps and considered the situation handled.

Pi-Thon Design developed its alternate means of fastening hoses and other forms of automotive plumbing in part to provide a positive means of sealing and fastening the connections, and in part to improve the appearance of said connections. The Hose Locks are machined from aluminum and come in two styles, both of which are offered in a variety of colors. Another of Pi-Thon’s product lines is Fire Lock, which are similar in design, but larger and machined from stainless steel for use with exhaust tubing. We got our hands on a sampling of Pi-Thon’s wares to examine and trial-fit to one of our test mules. Take a look. CC

	a & b. Pi-Thon Hose Locks are machined from aluminum to offer an alternative means of fastening hose ends. There are two main styles: the Hex Hose Lock and the Spanner Hose Lock. As the name implies, the Hex series are six-sided clamps that can be fastened using conventional wrenches (though AN-style aluminum wrenches would be advisable, to preserve the finish). The Spanner series Hose Locks are round with small, machined grooves to accept the dedicated spanner wrenches that fasten them, which are also produced by Pi-Thon	Most Hose Locks are three-piece assemblies—two halves containing a compression ring inside. The compression ring is machined with a tapered face to match the seats inside the two Hose Lock halves. When the halves are tightened together, the ring is compressed, squeezing the hose against the nipple it has been slipped over. Prior to installing the Hose Lock, the two halves should be disassembled to verify that the compression ring is not compressed at all. Hose Locks are shipped with anti-seize compound on the threads. This is vitally important, as they will gall otherwise.

Both the Spanner Series and the Hex Lock series are available in a variety of colors, as illustrated here.	The next step is to fit the hose into the Hose Lock. Proper sizing is critical, but shouldn’t be a problem since Hose Locks are available for hose and tubing in diameters of 1⁄4 inch to 2 inches. Both outer and inner diameters are taken into consideration when selecting the proper Hose Lock, and the Pi-Thon Web site has a detailed reference chart to assist. At this point the two Lock halves are connected together, but only with a couple threads. Insert the hose into the front of the fitting, which is the side with the larger internal diameter.	Now the hose, with the Hose Lock in place but loose, can be slipped over the tube end, which in this case is the radiator inlet. It’s a good idea to place the hose with the Hose Lock alongside the radiator inlet first to verify that the compression ring will clear the barb before the end of the Hose Lock contacts the radiator tank. In our case this proved not to be a problem. It’s important that the tube ends being used, regardless of the application, are barbed to ensure that the Hose Lock can seal the hose properly.

Once the Hose Lock is in the proper position, it can be tightened. Since we’re using the Spanner Series Locks, this requires a pair of the special spanners. The Hose Lock is tightened gradually until snug, or until the hose cannot be easily twisted over the barb. Since the Hose Locks are aluminum, care must be taken not to overtighten them, which could damage the threads.	Hose Locks are available for just about all of the hoses found in a typical engine bay (even some metric applications), and look fairly trick in addition to their clamping ability. Plus, they can be reused indefinitely, as long as the threads are properly lubed. The Spanner Series is shown, though the Hex Lock series covers the same applications.	We even experimented with Hose Locks on braided lines, both stainless and nylon. Obviously the braided sheath will require more clamping force to seal, but for low-pressure applications, the Hose Locks seem to work well with the braid. This is not, however, a substitute for actual A-N fittings in high-pressure applications.

Another variety of fastener from Pi-Thon is the Fire Lock, which is basically a big Hose Lock made out of stainless steel and intended for exhaust tubing. The Fire Locks are actually CNC-machined from T-304 stainless, and are offered for tubing sizes from 21⁄2 inches to 4 inches. There are applications to join butt-ended tubes of the same diameter as well Locks for overlapping tubes. Finish choices are between brushed or polished stainless for durability.

Our new generation fittings work well with rubber nylon braid & steel braid hose.

Available for 1/4"-2" ID Hoses

Hose-locks come Polished or Anodized

Red, Blue

An easy way to measure your hose is to use a piece of string for instance the max allowable hose diameter for our 1 1/2 fitting is approx. 6" or 5.990 over hose barb for 1 3/4 fitting it's approx. 6 7/8 or 6.86 max OD over barb.

Inch/Metric Conversion Table

9mm	=	5/16 (1A-05)
10mm	=	3/8 (1A-06)
11mm	=	7/16 (1A-07)
13mm	=	1/2 (1A-08)
15mm	=	9/16 (1A-09)
16mm	=	5/8 (1A-10)
19mm	=	3/4 (1A-12)
22mm	=	3/16 (1A-14)
25mm	=	1" (1A-16)
32mm	=	2" (1A-21)
34mm	=	1 3/8 (1A-22)
36mm	=	7/16 (1A-23)