(Note: LANDRACING.COM donations are not tax deductible)


This is a public forum. The opinions expressed here don't
necessarily reflect the feelings of The Folks That Run The Site (that's us)
unless we explicitly say so, ok?


Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 1040015 times)

0 Members and 1 Guest are viewing this topic.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3495 on: January 07, 2020, 02:11:44 PM »
These are the results of the buckling analysis for the aluminum axle spacer with an oily axle nut.  The safety factor is 1.19.  The spacer will not collapse.

The metal yield strength is a critical input.  Always use the 2 percent elongation value for yield.  Some manufacturers will post a different elongation, such as 10 percent.  This gives a higher value and it makes their product appear to be stronger.  The 2 percent yield value is the best one to use.   

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3496 on: January 07, 2020, 11:14:42 PM »
One thing I forgot to mention about that column buckling program.  It is tempting to download the results when you are done.  Do not do this.  The download file package has all sorts of bad stuff in it besides the printout.  Printing the results without saving or downloading has not given me any trouble.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3497 on: January 10, 2020, 02:45:06 PM »
This is how the wheel bearings are installed.  The object is to pull them in straight so as to not distort or damage the housing, have the top races positioned over the bottom races, and to have the bearings in the correct alignment when the central spacer between the bearings is compressed.

Some round things are made for this.  The holes in the centers are close clearance fits over the axle.  The outside diameters of the things are about 1/32 inches smaller than the outside diameters of the bearings, and the lengths are one inch.  Care is used in machining to assure that the faces are at right angles to the holes.

The bearings are pulled into the warm wheel using the axle and axle bolt.  Washers and other stuff are used as spacers to occupy the distance along the axle between the nut and the outside face of the bearing.   

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3498 on: January 10, 2020, 02:50:17 PM »
The axle nut is tightened to the manufacturer's recommended value.  These are 60 and 85 Newton-meters for the front and rear axles, respectively.  The nut torque is checked a second time after the wheel cools and the axle and spacers are removed.

Offline charlie101

  • Full Member
  • ***
  • Posts: 150
  • Age: 60
  • Location: Sweden, way up north
  • Indian 101 buff
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3499 on: January 10, 2020, 04:25:45 PM »
Timken has a nice brochure about setting tapered roller bearings.
https://www.timken.com/wp-content/uploads/2016/10/5556_Bearing-Setting-Brochure-1.pdf
« Last Edit: January 10, 2020, 04:27:43 PM by charlie101 »

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3500 on: January 12, 2020, 03:11:17 PM »
That is a good article about tapered roller wheel bearings.  My Matchless had them.  The Triumph has ball bearings so getting the inner races centered under the outer races are important.

Tapered roller bearing hubs cost more to produce but have more load capacity than ball bearings.  They handle side loads better.  The old British bikes would haul around sidecars.  Maybe that is why they used them. 

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3501 on: January 12, 2020, 05:57:27 PM »
Now it is time to design the outer wheel spacers.  There is one on each side of the wheel for four, total.  The design force is the axle tension with lubed threads having a 0.015 coefficient.  There are two faces for each spacer for eight, total.  The inside faces push against the bearing inner races and the calculations for the internal spacer will work for those.  Alloy 6061 T6511 aluminum will work OK.

One spacer is trapped between a die case aluminum fork leg and the wheel bearing.  The outer face of the spacer is larger to reduce the pressure on the softer fork leg material.  The calculations are similar to those recently posted.

The story is different for the spacer on the other side of the wheel.  The outside end of the spacer bears on the shoulder of a widened section of the axle.  There is not much load bearing area and design pressure is 32,400 psi.  Yield strength of alloy 303 annealed stainless steel is 34,800 psi.  34,800 / 32,400 = 1.07  That is a very low factor of safety.  It is like getting a D- in school.  Passing, yes, but barely.  Aluminum 6061 T6511 has a 35,000 psi yield strength with a 1.08 safety factor.  That is not good enough.  Triumph uses steel for these spacers on all of their bikes I have worked on, so there is a clue to what I need.  Steel rusts and is inappropriate.  Structural titanium has a 141,000 psi compressive yield strength with a 4.35 safety factor.  The spacer is made from that and another problem is solved.

Structural titanium is often called Ti-Al-4V due to its primary alloying constituents, aluminum and titanium.  In many ways it is easier to machine than the stronger stainless alloys and it resists corrosion, is lighter, and much stronger.  It is very easy to get a much smoother finish than stainless.  The finish on the spacer is cut with roughing bits.  It is better than I can get on stainless with finishing bits.  It is my "go-to" metal for a steel substitute when making bolts, spacers, and other small items.           

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3502 on: January 17, 2020, 11:12:58 AM »
These posts are about doing basic things for folks that are not familiar with the details.  Machining, unfortunately, is becoming a lost art.  None of the equipment or materials in these posts, except a rod from India and some other small bits, were purchased new.  Folks with used machine tools are selling to a very limited market and the prices of the equipment is low.  Sort of like trying to sell used racing parts.  A lot of things were given to me just because I had interest in using them.

Ten aluminum bolts are needed with metric threads and holes for safety wire.  These are not available here unless I order a box of them and wait awhile for delivery.  Then I need to drill them for safety wire.  It makes sense to spend a few hours and turn them from rod stock.

Most of the new metal in this area of Oregon is of foreign manufacture and it is imported 'cause it is cheap.  This rod is an example.   It is sold as 1/2 inch but it a few thousanths of an inch too big to fit in a collet.  It is an aluminum alloy of unknown pedigree and I tried to make a bolt from it once.  The shank twisted off during threading.  The metal was weak.  The other rod is from a used metal scrapyard.  The alloy is printed on the rod and it is the correct one for bolts.  The diameter is correct so it will fit in a collet.

When I find good metal I buy it if the price is right and stash it away for future projects.  The 12-foot rod cost $10 so it goes into the scrap pile for future use.

       

   

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3503 on: January 17, 2020, 11:25:42 AM »
This is an Ellis indexing head.  It is in the horizontal position and it can also be set for vertical and any angle between.  This would be a good tool to own if one has a drill press or vertical mill.  They come with collets and a chuck.  A collet is used to make these bolts.  The rod is clamped in different positions in the collet to mill all of the hexes for the heads.  The head is bolted to the drill press table and a mill bit is clamped in the drill chuck.       

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3504 on: January 17, 2020, 11:30:36 AM »
The rod is clamped in the collet and the drill press table is slowly rotated under the cutter to cut the head.  This is a manual operation and it takes a bit of practice to get the feel of it.  Hex heads for all ten bolts are cut into the rod.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3505 on: January 18, 2020, 01:13:36 PM »
The rod is put in the lathe collet.  A punch mark is made 1/16 of an inch out from the hex.  This is the shoulder and it will not be cut.  Another mark is punched an inch out from that.  It marks the end of the bolt.  The rod is pushed into the collet and clamped.  This shorter projecting length reduces chatter during the cutoff.  The excess rod is cut off using a parting tool.

The rod is pulled out of the collet so the hex is exposed.  The parting tool is used to mark where the end of the bolt will be.  The cut is only deep enough to mark the end.

 

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3506 on: January 18, 2020, 01:28:29 PM »
The rod is pushed into the collet until 1/32 of its 1/16 length is exposed and the other 1/32 is clamped.  The clamped portion of the shoulder gives support for the rod during subsequent operations.

The tool bit is positioned at the punch mark.  The carriage stop is clamped so the tool bit cannot move beyond the punch mark.  The threaded portion is cut to the major diameter.  This is 8.00 mm for this bolt.  Some tough metals will deflect while being cut and the far end of the cut portion, at the bolt end, will be wider than the cut portion near the collet.  The cut portion diameter should be measured and additional passes may be needed to get the same diameter at both ends.  A very sharp finishing bit with higher turning speed is needed with some types of stainless steel to get the desired diameter at the unsupported end.   

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3507 on: January 18, 2020, 01:42:43 PM »
A 45 degree champher is put on the end with a file.

This is an 8 x 1.25 metric thread.  The top of the thread is flat with a 0.16 mm width as shown on the page from the machinist's manual.  A die will be used to cut the threads.  A die cuts and deforms many tough metals so they grow in diameter inside the tap while cutting.  Instead of a flat thread top, the top is sharp and pointed.  This jams the tap, reduces its life, and a lot of force is needed to cut the threads.  Often, cutting the threaded portion to a slightly smaller major diameter before using the die will produce a thread with the desired flat crests.  This is much easier to cut with the die.  This I do by trail and error to figure out the best reduced major diameter.  Titanium is a metal that almost always requires this.     

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3508 on: January 25, 2020, 12:23:09 AM »
Eight millimeter diameter bolts are being made.  Eight millimeters are equal to 0.315 inches.  The rod to be threaded would be turned to this diameter in the past.  Now I measure the diameters of the threaded parts of several new 8 mm bolts.  The diameters range from 0.304 to 0.310 inches.  The target diameter for the new bolt will be 0.308 inches, or sorta midway within that range.

The rod is turned to 0.308 inches for the first trial.  Some threads are cut with the die.  The thread crests are sharp edged and the diameter is 0.312 inches.  This is too big.  The alloy is deforming while it is being cut and the threaded diameter is too large.  A new bolt is turned with a 0.300 inch diameter for the section to be threaded.  It is 0.308 inches diameter after the threads are cut and the threads have flats on the crests.  All of the remaining bolts are turned to 0.300 before thread cutting.

This method has saved me all sorts of struggle when threading lots of alloys and especially titanium and the gummier stainless steels.

The first picture shows the rod pulled out of the collet so the flats are exposed for the bolt head.  A wrench will be put there in a future step.  The wrench is shown in the picture.

The second picture shows the die.  Adjustable dies were used on some tough alloys and they spread apart while threading and the bolt diameter was too big.  Now I use one piece dies for the tough metals.  The dies are used to cut a particular metal, only.  A die used to cut ti will not be used to thread brass, as an example.

Lube helps.  The stuff shown in the picture works good for most metals.   




Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5346
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #3509 on: January 25, 2020, 12:33:43 AM »
The die is started by turning the collet by hand and using the center as a brace as shown in the first picture.  This keeps the die square to the shaft.

Now the center is slid back and the die is turned by hand to make the threads.  Rods made from the tougher metals would turn in the collets or chucks when threading.  The wrench-on-flats restraint prevents the rod from turning.     

The threads are made and the hex sides are punched for the safety wire holes.  The partial cut that marks the bolt end makes it easier to center the punch mark on the flat.