CHOP CULT HOME
Email Password
Search
Page 1 of 2 12 Last
  1. #1

    Join Date
    Sep 2020
    Posts
    3

    Default Milling/Boring out pre 82 Paughco Ironhead frame ro run a 1" Steerer?

    Hey guys!

    Maybe a bit of an odd question, but I picked up a project bike built up from an ironhead paughco frame and a 79 ironhead. I was intending on rebuilding everything, and on running a moto iron springer with a 1 inch steerer. I was assuming if the fork was 7/8ths once a pulled it, that i could just press neck cups in and convert it. However once i had everything ready to go and parts in hand a found out that the way the neck is machined that it narrows in the middle with a permanent sleeve of sorts. I was adamant it was a pressed in sleeve because I didn't know these existed and most of my friends agreed that it was pressed in after txting photos around etc. So I went to hammering it out and of course it wouldn't budge. I then resorted to cutting it out with a hacksaw to release it that way and then found out it was definitely attached. Bonehead move, but yolo i guess. Anyway frame is still structurally sound so no worries there, but I'd really like to continue the project as is. I like the way the frame sits and its oldness etc. So i was wondering if you guys have ever heard of anyone milling out the neck to get rid of the middle section and widening it up that extra bit? Or if anyone has done it personally It looks like everything will still be of adequate thickness and I have access to a mill at work.

    Click image for larger version. 

Name:	IMG-1948.jpg 
Views:	2 
Size:	277.3 KB 
ID:	106447

    I also contacted Paughco just to see if this neck sleeve was put in/machined by them and it turns out it is. And then I got yelled at for not knowing the rake of the bike and the exact springer measurement (even though i did, different places just measure them differently) and for taking measurements like a child by a very surly fellow. As well as the usual "if you do anything to that frame I cant guaranty your safety" when I asked i anyone had milled these before. I did learn that old sporsters have a 5 inch neck though so that is useful.

    Anyway any info on this is appreciated! And if any ya'll think I should just pony up and have a frame built the way I want lemme know that too! This is my first build and i'm pretty adamant to make it look the way I want. Even if it takes forever.

  2. #2
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2017
    Posts
    2,718

    Default

    What is the ID of the smaller bore?
    What is the ID of the larger bore? same top and bottom?

  3. #3

    Join Date
    Sep 2020
    Posts
    3

    Default

    So, top and bottom both read at 1" 11/64ths on my calipers (so I'm assuming 1" 3/16ths is the actual measurement), the smaller bore is about 2 inches long and recessed around 1" 1/2" from the top and bottom. I cant get my calipers in there to get a good enough reading but I would say around 15/16ths of an inch by eyeballing it.

  4. #4
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2013
    Posts
    9,426

    Default

    The narrowed section makes no structural sense considering where the load is (the bearing areas). You'd be taking out very little wall to make the cut and their choice to not bore that section is obviously to speed production. They didn't NEED to cut that amound of metal x (frames produced) so they did not. Time is money and so is tool wear.

    Mill that bitch.

  5. #5
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2017
    Posts
    2,718

    Default

    That center section is not needed to be a size with a certain tolerance, as the bearings fit into precision cups at the top and bottom - just drill it out.

    So the steering stem for the moto iron springer has machined areas at 1" diameter for the bearings near the top below the threads, and near the bottom above the step,with a non-precise area between at less than 1"...and it does not fit through the frame neck?

    Drill it or mill it out to 1" plus 1/16", up to the size of the larger diameter inside the frame neck...just provide clearance for the springer neck post to fit up into the frame neck from the bottom.

    Here is a Moto Iron 1" springer neck post:

    Click image for larger version. 

Name:	31cxsx4pSGL._AC_.jpg 
Views:	0 
Size:	6.0 KB 
ID:	106471


    Installation of a Moto Iron springer;

    Gotta Have A Springer

    Article and Photos By: Daniel Donley
    Originally Published In The February 2017 Issue Of Cycle Source Magazine

    "For this month’s tech I am going to show you how to install a Moto Iron Springer front end on our new frame..."
    https://cyclesource.com/gotta-have-a-springer/

    Note: they missed one photo on the install and duplicated the pic of tightening the pinch bolts on the top tree... the words say this:
    "This is the bearing tensioning nut. You will want to tighten it down until you feel slight resistance while moving the front end from side to side. You do not want it loose and floppy or the bike will shake on a deceleration. If you have it too tight, the bike will respond sluggishly and feel tight."...

    the bearing tension nut fits above the top bearing and upper dust cap,below the top tree. See it in the photo below the top tree,just not a great photo for that part of the install.

  6. #6
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,043

    Default

    You will have to fixture this frame very rigidly on the mill table, which might take some imaginative clamping. Then you can just drill or single point bore it out. It's just clearance, so no real precision needed. If you have a 1 1/16 drill that is long enough, that will give you all the clearance you need. For opening up an already large hole, one trick is to dress a radius on the corners of the cutting lips on the drill bit to make it more controllable. Very low rpm, of course.

    The other consideration is, will the ends of the frame neck accept big twin bearing cups, which are going to be essential to fitting a fork with a 1" stem? The cups for the typical Sportster stem are smaller. If you have to also cut the frame neck at top and bottom, that is a much more precise job and critical to the fork installation. If all that needs to be done, it might be easier to replace the steering head on the frame with one for a big twin. And of course another alternative is to change the fork stem for an XL style stem (which may be the easiest answer in any event).

    Jim

  7. #7
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2017
    Posts
    2,718

    Default

    Ironhead Sportster 1" Fork Cup Conversion for Big Twin Front Ends

    "The Original Made in USA Fork Cup Conversion for Sportsters.
    Beware of chinese copys out there!

    Our Kit consists of a set of steel fork cups, machined to fit a 1957-1981 XL Frame.
    and Billet aluminum dust shields that are machined as spacers to bring the neck to the same length as a 1" big twin neck.

    Replaces your stock Ball Bearing Fork cups.

    This will allow any stock or aftermarket big twin front ends and springer front ends to be used on a sportster.

    Fork Cups are Nickel plated for rust resistance

    Includes new bearings and races"
    Click image for larger version. 

Name:	4448.jpg 
Views:	106 
Size:	3.6 KB 
ID:	106473
    https://secure.vulcanworks.net/store...ront-ends.html
    Last edited by TriNortchopz; 4 Weeks Ago at 7:20 AM. Reason: pic

  8. #8
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,043

    Default

    Quote Originally Posted by TriNortchopz View Post
    Ironhead Sportster 1" Fork Cup Conversion for Big Twin Front Ends

    "The Original Made in USA Fork Cup Conversion for Sportsters.
    Beware of chinese copys out there!

    Our Kit consists of a set of steel fork cups, machined to fit a 1957-1981 XL Frame.
    and Billet aluminum dust shields that are machined as spacers to bring the neck to the same length as a 1" big twin neck.

    Replaces your stock Ball Bearing Fork cups.

    This will allow any stock or aftermarket big twin front ends and springer front ends to be used on a sportster.

    Fork Cups are Nickel plated for rust resistance

    Includes new bearings and races"
    Click image for larger version. 

Name:	4448.jpg 
Views:	106 
Size:	3.6 KB 
ID:	106473
    https://secure.vulcanworks.net/store...ront-ends.html
    Yeah, those things are thin, thin, thin. I wonder how many of them will end up broken, sheared off at the corner. Certainly a clever adaptation, but no thanks.

    Jim

  9. #9
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2013
    Posts
    9,426

    Default

    It would be interesting to know the actual dimensions and material of the Vulcanworks cups.

    A stepped round bar could turned (to steering stem length plus enough for the collet) then slid into the neck and chucked in the mill collet to hold the neck square to the quill while OP figures out how to hold the frame to the mill table. Bolting some stout angle to the mill table and tack welding it to the frame (with the ground clamp safely on the frame not the mill) could make a simple fixture. It only needs to be strong, not pretty.

    Drill neck as JB describes, grind off the tack welds and done.

  10. #10

    Join Date
    Sep 2020
    Posts
    3

    Default

    Thanks guys! Really appreciate all the info. Should get it all sorted this week!

  11. #11
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2010
    Posts
    38

    Default

    You'd have to have a huge mill to bore out the neck. a bridgeport wouldn't even come close. Probably a true boring mill is more like it. Not sure if I'm following correctly But my suggestion is to determine bearing sizes required for top and bottom. Im assuming common id for the shaft, different od for the difference in neck id dimensions. I have a gsxr front end on my paugho frame and thats what we did. Did have to resize the od of the shaft in a lathe. Worked well.

  12. #12
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,043

    Default

    Quote Originally Posted by axel View Post
    You'd have to have a huge mill to bore out the neck. a bridgeport wouldn't even come close. Probably a true boring mill is more like it. Not sure if I'm following correctly But my suggestion is to determine bearing sizes required for top and bottom. Im assuming common id for the shaft, different od for the difference in neck id dimensions. I have a gsxr front end on my paugho frame and thats what we did. Did have to resize the od of the shaft in a lathe. Worked well.
    A Bridgeport would do this job just fine.

    Jim

  13. #13
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2013
    Posts
    9,426

    Default

    My old round ram would manage it easily. There is no need to bolt a frame to the table and tilt the head unless you have convenient access to a boring mill. Fixturing a neck for a mill is a bit like welding tabs on heavy equipment for line boring except the fixture/tabs would bolt to the T-slots on the table instead of pillar blocks and the line borer.

  14. #14

    Default

    I did something similar with a hole saw and a piece of pipe inside it. Used a drill, high speed, and a lot of cutting fluid.

  15. #15
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2010
    Posts
    38

    Default

    Hi Jim. Ihave a small mill but use my friends bridgeport on a regular basis. How would you table a bike frame on a bridgeport?

  16. #16
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,043

    Default

    Quote Originally Posted by axel View Post
    Hi Jim. Ihave a small mill but use my friends bridgeport on a regular basis. How would you table a bike frame on a bridgeport?
    As I said above, imaginative clamping. It would be awkward at best. But a Bridgeport spindle has 5" travel, so the actual drilling or boring is well within the mill's capacity.

    Farmall suggested welding supports to the frame after squaring the steering head to the machine spindle.

    Remember, you can hang a workpiece off the table, or even under it if the height is an issue.

    Jim

  17. #17
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Jul 2013
    Posts
    1,209

    Default

    A far easier route would be a brake cylinder hone and telescoping gauges (read them correctly). Re-boring would be difficult to center and plumb and making a fixture is time consuming, no machine shop in their right mind would take that work, even friends. You have friends that would you ain't treating them right. You're only looking at 32nds here and in all actuality it's more apt to fuck it up if it's bored off plumb, center or loose in the jig.
    When you turn something on a lathe, you don't use a cutter to get another one to three thousandths. You get the sandpaper out. That's all the OP needs to do in this case.
    Last edited by seaking; 2 Weeks Ago at 2:35 PM.

  18. #18
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,043

    Default

    Quote Originally Posted by seaking View Post
    A far easier route would be a brake cylinder hone and telescoping gauges (read them correctly). Re-boring would be difficult to center and plumb and making a fixture is time consuming, no machine shop in their right mind would take that work, even friends. You have friends that would you ain't treating them right. You're only looking at 32nds here and in all actuality it's more apt to fuck it up if it's bored off plumb, center or loose in the jig.
    When you turn something on a lathe, you don't use a cutter to get another one to three thousandths. You get the sandpaper out. That's all the OP needs to do in this case.
    One, it's just clearance, so no real precision is needed, i.e., you can drill it out.

    Two, I'd like to see you take 1/32 out of a steel bore with a brake cylinder hone. Surely you are joking, or you don't know much about tools.

    Jim

  19. #19
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2010
    Posts
    38

    Default

    I get it. I didn't think of hanging the frame.

  20. #20
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Jul 2013
    Posts
    1,209

    Default

    Quote Originally Posted by JBinNC View Post
    One, it's just clearance, so no real precision is needed, i.e., you can drill it out.

    Two, I'd like to see you take 1/32 out of a steel bore with a brake cylinder hone. Surely you are joking, or you don't know much about tools.

    Jim
    Not like your advice is gonna get him anywhere, either laughed at, big $$$ spent or sitting in his bud's garage for a year. If it's just clearance go at it with a hole saw.
    Last edited by seaking; 2 Weeks Ago at 8:31 AM.

Share This



Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in