In the process of building the struts, being that it will be a heavy rig (Road King and 1.5 fiberglass dusting replica boat) I was thinking of useing 7/8" clevis inside a 1"id pipe with weld in ends. Possibly heims on the other end.
Question: Ive seen elseware 3/4" clevis used, is this strong enough?
Is 7/8" 14 tpi as good as 7/8 18 tpi for strenght and adjustment
How do the heim joints hold up over time? do they flog out and
get loose
Given the whole thing is only as strong as the weekest point I'm just wondering if 7/8" is overkill
This will be a dedicated rig and I dont envisage ever takeing the sidecar off except for sevicing. I've decided to use a Unit leading link as oposed to raked trees, has anyone had any expieriece with their product.
Thanks for your input and for the input on my other questions, its much apreciated.
Tim, Airlie Beach. Australia
Tim,
1" schedule 40 pipe should be quite sufficient for the struts. If this is to be a rigid mounted sidecar why would one need to use Heim joints when a simple clevis and eyebolt connection at either end would serve the same purpose?
5/8" or 3/4" clevises are often used for the lower sidecar mounts but the upper struts are simply props and take a lot less strain than these connections.
Lonnie
Northwest Sidecars
Thanks Lonnie, My mates a boilermaker and I think he's trying to build me a tank, so your saying that 3/4" thread on the clevis is sufficient for top and bottom mounts given this is a 11/2 hack. I have read a lot of posts that say you cant over build it but there is a limit I presume. I agree on the Heim but thought for alligning it might make things easier.
Thanks again
Tim
Not a big fan of heim ends being used for mounts especially on struts.Also not real fond of welded on ends for struts. Just my opinion of course.
We make a clevis and eyebolt system that works good.
The tubes themselves are 1 1/4" x .120 wall DOM tubing. Threaded inserts are TIG welded into the ends. It is much preferred to use straight tubes for strength and also ease of adjustment. If we happen to need a bent tube for any special applicatin we will insert a piece of 1" OD tubing inside prior to bending so as to not have any flex. See attached.
As far as the leading link goes Unit makes a very popular leading link with very few issues related to it.
Thanks claude, Yes I meant weld in threaded inserts as you sugested.
So I guess the general consensis would be the 3/4" thread is strong enough and no need to go 7/8"
Thanks again
Tim
In a US company were I worked I got told by the boss's sun that each time he ordered me a row boat I presented him a Bismark battle ship.
Anyhow practically all my designs in the last 18 years run, work and produce still without mayor maintanence work.- they broke their company.
=> So who was right?
In your case: "What happens when your selfmade design will break in the middle of nowhere?"
I was told that in Aussyland there are quite bad roads and lot of open land with nasty snakes etc...
I'd better pay a few cents more for a little overkill as you say and use a Schnappsglas more of gasoline per 100km, but go the safe way.
Welding is in 90% a bad construcction practice and only 1% of all welders will make you a decent job. Forged or mill out of the full material of good quality is a safe way to work. On the tubeing you shouldn't save. I recommend for joints hard soldering with brass. It takes its skill and time, but it is much safer.
2 Cent from Costa Rica where you not even empty a tank before you hit with a border or ocean.(I'm quite yeallous on you in that aspect)
Sven Peter Pan
A good brazed connection at 50K psi tensile strength vs a good welded connection at 60K to 70K psi tensile strength. Either will work well.
The main point here is a good bonding job using materials of adequate size and strength.
Lonnie
If the weld in question is a tube being inserted into a tube a plug weld in addition to welding around the two tubes will practially guarantee no failures will happen.
If the inside piece of tubing is a threaded slug be sure to run a tap through it after welding in case the threads were distorted. Also it is a good idea to stick a bolt into the threaded end slightly when welding so no spatter gets on the internal threads.
Peter Pan wrote:
>>>I'd better pay a few cents more for a little overkill as you say and use a Schnappsglas more of gasoline per 100km, but go the safe way.<<>>Welding is in 90% a bad construcction practice and only 1% of all welders will make you a decent job.<<>Forged or mill out of the full material of good quality is a safe way to work.<<> On the tubeing you shouldn't save.<>I recommend for joints hard soldering with brass. It takes its skill and time, but it is much safer.<<
I am not that that familar with this type of construction. Apparently many others are not either as it is not common. The statment says:" It takes its skill and time, but it is much safer. This alone sways me from thinking it is a better way to go. Why? Ask who has the skills needed to do it right? In over 30 years of being in the welding and fabrication trade in one capacity or another I do not know of anyone who uses these preactices on any type of a regulkar basis.
Futhermore,In light of the first statement that I already commented on that said "Welding is in 90% a bad construction practice" I can only say that if that were true and we were stuck with brazing to do a safe job we would probably be in trouble. We might as well scrap all the motorcycles and sidecars we are riding.
Again, sorry to sound difficult but I just cannot just sit back and listen to things being stated as fact that negate normal and accepted GOOD fabrication practices that are time proven and now being alluded to as bad or substandard methods.
One more comment that may have already been made.
NO assembly is any stronger than it's weakest point.Typically that point will be a connection of some sort. In our sport this is not always true as the bike frame itself can be the weakest point. It is good to beef up the mounts and so on but the parts of the assembly that will be carrying these mounts must also be up top the task. Building a strong subframe to add strength to the bike is important. This is especially true on rougher roads at speed. If you have a small bike and are just piddling around in slow motion maybe things would be fine but when the anty is upped streeses go up real quick and failures can be much more 'spectacular'.
as a millwright,..............I gotta agree with claude on this,..brazing is a viable option in some instances if done perfectly, but welding is much stronger with correct design,.....the world around us is welded together for a reason!!!! cheers,
OK, friends,
I will not argue or flame arround, that is not at all my intention.
As Claude states the material selection and design are essential and should be left to experienced specialists.
Nowerdays with MIG-welding you can make marvells and in many countries you find excellent welding specialists. I will not argue about that.
Brazeing had been the main assembling technic for motorcyle frames until the seventees because it permits with enough overlap flexible joints. In sidecars you need flexibility in the frame as in airplanes. A rigid frame
will break very fast. (ask a motocross sidecarist about that, what he will state) That's the reason why I will never use for example 7018
electrical welding rods on a truck or bike frame because of the brittleness it causes.
My comment is mainly about many "want to be specialists" and I may tell you here in Latinamerika those are the huge mayority and often bring up designs that are very dangerous!
I hope that I didn't stirr up too much your minds. As an engineer I overreact frecuently when I see somebody building something that might put him or somebody else into danger. And who of you will negate that a badly designed o built rig frame is a public danger?
I had enough with haveing to spend "last auxilliaries" 3 times.
For now have a good night, dream of your next pleasant trip and enjoy every single moment of life. Its a divine gift.
---
On my shirt I wore for a long time the button:
"I am allways in trouble,-
but its so much fun!"
And to that time my Norton Comando had the sticker:
"Don't take life so seriously -
its only temporary!"
---
Enyoy it!
Best regards from Costa Rica
Sven Peter Pan
LOL..Pan,,,..at least your enjoying the sun and decent riding weather there!..I've got 4 feet of snow at the end of my driveway,...hehe... we all get cabin fever this time of the year,..cheers, crawf.
Yes Pan it i sall about having fun and doing it safely. Now about welding those truck frames....lol...just kidding.
Be well and keep posting 🙂
Thanks for you Input. The guy doing the welding is an excelent tig welder and has done bike frames etc for years. Fabricates parts etc. I have had three outfits before and fitted one myself so have a reasonable idea on the forces put on the mounts and bike.
I will post some photos when its all done in about 2 or three months ( will be waiting on the leading link from Unit ). You may be interested in the upper rear strut going through the pannier.
Thanks again
Tim
