I screwed up and need to know how not to do it next time. I thought 3/8 ID would be 3/8 ID but looks like its not. Ordered new lines and measured the ID of the fitting so choose same size lines and fittings. The lines are labeled 3/8 ID and are smaller then the ones removed, but so are the fittings. What should I order next time?
I found this chart helpful to ID JIC fittings https://toplinemachinery.com/pages/jic-fittings-size-chart
Looks like your original was #10 and the replacement is #6 . Then you have to consider is it JIC or SAE. They're a bit different at angle of seat and diameter, particularly at #6 .
Thanks, but that just made things worst, across the male threads is 11/16 on outside edge
This is on my D3B, what fittings does CAT use?
That machine is most likely all JIC for the hydraulic flare fittings. These sizes correspond to what wrenches I use to take the female nut off, with the caveat that "some" Caterpillar fittings are 1/16" bigger than shown. For example, a Parker -6 needs a 11/16" wrench, but a Caterpillar -6 may take a 3/4" wrench.
Used Great G Dad's vernier caliper (no dial) and outside micrometer, threads are just barely under 3/4, so probably are 3/4 Wrench size is 15/16 (7/8 to small and 1 is sloppy) The chart post by The Peej shows it to be a -8, and may also work out be correct if adding a 1/16 to heymccall post
If the -8 is correct, then would it be recommend to also use a larger ID line instead of 3/8 ?
Jump sizes are more rare, but Cat does use them. When in doubt, measure the ID of the hose, after cutting it. From the Caterpillar hose book.
Thanks, have always thought that what ever piece has the smallest ID inline would restrict the flow. If the lines are 5/8 ID and the fitting has a 3/8 ID, then the fitting will reduce the flow. Probably missing something, but will cut one open. Buying hoses from www.hoseinahurry.com Prices are great and received first set in 3 days
Sorry but that's not true. A 3/4" thread measures 3/4" across what's known as the Pitch Diameter. This is a diameter measured approximately halfway between the top (Major) and bottom (Minior) diameters of the thread. See below but note that the Minor diameter is not shown on the illustration. What you are measuring is the Major diameter and that is not the same as the thread size. Fast delivery makes no odds if what you receive doesn't fit......... I can't see from your photos exactly where the hose is connected to (at both ends). With that I can problably find a Cat Part Number for the hose which will give the Part Numbers of the fittings used to make it. Those numbers will identify the fitting type and size. Question: How many threads per inch is the conical fitting that is shown in your photo.?
These are for the lift cylinders on the D3B Pitch gauge shows 16 threads per inch Measured lengths are 29 and 47 inches
Hose Assy 068-7366 (23 inch hose) and 5G-1791 (42.13 inch hose)
They are dash 8 hoses and dash 8 fittings 1/2 inch. Bob
Based on 16TPI Bob's right that they are Dash 8, but are they SAE or JIC.? The stems for both ends of a Cat hose are an 8S-4055. Maybe someone can look up the number to confirm if that number is JIC or SAE. I'm just about to head out of the door.
They look closer to 37 degrees then 45 but that's just trying to use a hand held angle gauge
Jic -8 -8 reusable, 3.39" cutoff factor 3.39+3.39+23=29.78" overall length. Same cutoff factor a permanent stem. Calls for 4k psi hose.
Jic -8 -8 reusable, 3.39" cutoff factor 3.39+3.39+23=29.78" overall length. Same cutoff factor a permanent stem. Calls for 4k psi hose.
Thanks so my 29 and 47 are pretty close But with the sheet, I'm seeing 1.73 from end of hose to end inside fitting. So wouldn't this be 1.73 + 1.73 + 23 = 26.46?
Yup. My mistake. Your math is right.
Thanks much
With an 8S-4055 reusable fitting on each end the length of hose required to fabricate the 068-7366 is called out as 60 cm (23.62 inch). For the 5G-1791 also calls out 2 x 8S-4055 and the hose length is called out as 107 cm (42.13 inch). That ought to be within the ball park but is not guarnateed to be 100% correct. With crimped non-reusable fittings the cut length of hose required to give the correct overall length might change by a little.
Thanks much, I ordered lines based on overall lengths (27 and 46) so it should fit using the preliminary lengths used with my tape, and they were a bit long.
Nige, I have to disagree with you. Most all standard screw threads are called out by the nominal major diameter. The outside diameter of a screw thread will almost always be under the nominal thread size by an amount that is roughly 1/10 of the thread pitch. The pitch diameter is only of concern to machinists, and is usually measured using special pitch mics or with thread wires. For example, the -8 in the illustration is 3/4-16. The thread pitch is 1/16", or .0625. 1/10 of the pitch is .006, so the measurement of the od of the threads will be about .744.
You're absolutely right. I have no idea what I was thinking when I wrote that, although a pending dental appointment this afternoon could have had something to do with it. Humble apologies.