Building Springers Yokes

[Vambo]

My apologies if this has already been covered.

Im looking to build a set of springers for my chopper trike project. I am a competent engineer, have access to a lathe and a not very good warco milling machine. my question is, how would you guys get a decent precision cut on the holes in the yokes for the forks to pass through (1 1/2")? can make the yokes from ally or mild steel.

many thanks

[Nobby the Bastard]

[Ste]

[Nobby the Bastard]

[stinkwheel]

I'd find someone who DOES have a good milling machine and get them to do it.

You can prep and mark the piece to save time and expense.

It's that or potentially screw it up if you don't trust your mill.

I'd think a trike would be much better with an Earles or leading-link system for lateral ridgidity.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Easy-X]

[steve the grease]

Not really a forum for machinists. Although this section is titled "The workshop" Many of the people on here struggle with technical challeges like ' no brake light' or 'bike won't start'. I suspect that the number of non-sarcastic replies will be rather limited. Finding someone who does have a proper milling machine does sound like an excellent place to start. Having a proper drawing would be another good suggestion . Oh, and get a quote first, Solicitors seem very cheap compared with CNC machinists, in my experience. Have you seen this: https://www.ebay.co.uk/itm/8-Wide-Build-Your-Own-DIY-Springer-Front-Forks-Kit/143102590066?_trkparms=ispr%3D1&hash=item2151943c72:g:vyIAAOSwQfRcSdU8&enc=AQAEAAACQBPxNw%2BVj6nta7CKEs3N0qUV0kQW7PvYl8cnqNNEmZZywO4X%2B78LSY1pqnqUBSCXZo2sX%2FOlayc9SNZWoa2n%2BU9Y%2F0MfmJ1J623ZnEWzr8M7bGd28GDvy8%2F0BMv6o3HErL%2BAiNDCjhNfUXZXvRJJRJawCIsLDrUTmaucnw3TuiRhgJ13LC4Ej7k6Hc7FYqw%2FX%2BSmYeDEzayJ2b%2B0zCQO29mXREmaWNOXvKYXJktv4KhIY0LxoGdcQqwqHbEvVm8pi0YgOKJMsd0wO7n5Ad8BVAbqs4LgkbgsV6qaAEMq26vwpvyw6LcYpMZQztfz8TyeRp2WHgyHuW6q1IK%2F%2FjA1aUTwZDcX9VSL%2BzWDAStWPGLVjLS6ogFiPCPvsHEaME4fsvZU3rIbVu5sjZiyISX7du%2F7xu3sFSYTuQKeOMEi5sFvV49u9CCmJfHfuxBCGy458EUjL9mXYEfG3su2amtsRZkeGhduDEif2jJseUeDHL2zbjJVMFWTK7%2F3n7DkOaUE8%2FBkCaWQ97kOSLstntRg%2B62skT6JIIzc6UrK9rN5x9PFt%2FMfU4qJMmNUhe33XTR%2FR4viHUoS9Dlfm4WhQb%2FlwAky5IKSUGp5c6zcc8GNtXZ6dQX55RK7MHkloGERBDrG9YpEWL6kqX9tvuBZCpMAgRVVHxj9GcqLt9cPLvMf5Vl1Sf%2BzHvLggqdYXlykq828KnIfBMfmqVppcDy6pFL%2F4XdnIBf7GIWAHI8Gpax4MYF8ewYVrF6LfjkbX10b%2F0KFjg%3D%3D&checksum=1431025900662064211e194d4bd7b53420e8f4cb1f65
Getting the rockers right is the worst part, the yokes are fairly straight forwards.

[stinkwheel]

Hell.

if you are building from scratch. Go hub-centre.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Teflon-Mike]

The term 'Springer' fork, is significantly a Harley/Cruiser vogue..... b-u-t..... The 'springer' type fork is actually just a 'sprung' girder fork, and whilst they are more popularly associated with cruisers and customs, because of they were the more usual and effective form of fork in the 1930's thru '50's that were on the bikes that were chopped in that early 'Chopper' era of the cruisers and customs, and the 'Springer' name was, I believe, actually a Harley Davidson 'Trade-Mark', b-u-t it isn't something exclusive either to Harleys, cruisers or customs. NOR is it actually such a Luddite bit of antique engineering, curiously,.

Through the 1960's the telescopic fork became the usual, mainly because its actually quite cheap to make. The main gripe against them is a thing called 'Sticksion', where the lower leg, sliding on the upper 'sticks' rather than slides, more so if the forks under any sort of bending load, resulting in a very high initial resistance to travel, but you can get a lot of axle-travel from them, and with all axle travel in a straight line, co-incident with the fork-leg telescoping, they 'can' maintain steering geometry pretty well.

On side-cars the 'Earles' type fork, with leading arm swing-arm on the fork, was., and I believe still is, popular for avoiding sticksion and offering much better high-load geometry control, problems which lead companies like Honda to try tackling in GP racing with very high tech, mandrel wound carbon-fibre fork tubes, and high tech chrome and titanium plating, and low friction 'teflon' fork bushes.

Probably most noteable, though, is the 90's 'Britten' racer; the ultimate shed-build; Kiwi John Britain built his incredibly high tech Fibre-Flyer, for antipodean 'BEARS' British, European, & American Racing (But shunning all nationalities!) wanted 'his' bike to be totally home-brewed with no foreign assemblies, so to make a front fork/suspension system, not using anything from Japan, and significantly in Carbon Fibre, he actually went on record, as saying that the design he eventually settled on was a modern take on the 'Girder' or 'Springer' Fork...

It's NOT necessarily, a 'Hill-Billy' set up, or low-tech... though it most usually is!

What was the question again?

[stinkwheel]

Point of order, the Britten has a Hossack fork. Like a BMW.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.