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Front ends on MRRC cars with the Sebring chassis

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  • JML
    Championship Contender
    • Jan 2006
    • 2171

    Front ends on MRRC cars with the Sebring chassis

    I picked up my first MRRC car with the Sebring chassis, the Chaparral 2F. Unlike the Sebring chassis used in the Monogram cars, which has bushings front and rear, the front end of the MRRC version has two pairs of 3/32" diameter, but greatly elongated, vertical axle slots, resulting in much too much play in all directions, most notably vertically. I'm pulling the axles and wheels, substituting Slot.it axles, an offset crown gear, bronze bushings in the rear, and BWA 32002/32004 wheels with inserts.

    I've been mulling over how to correct the front axle travel. I have several sets of the Slot Car Corner axle posts, which use opposing set screws to set axle height, and was considering trimming the chassis reinforcements and using them, but the chassis is angled (not parallel to the ground) and I'll have to reshape the bottom of the SCC posts to correspond to the vertical slot, and then deepen the SCC posts' vertical slots to match the Sebring chassis slots. The SCC posts might also be glued on the outside of the chassis, but I'd still have to trim them at an angle and they'd have much less chassis-to-post surface area for gluing.

    A 1/8" OD x 3/32" ID brass sleeve would work, but drilling two enlarged holes on both sides of the chassis is not easy and I'd have to glue the sleeve on the bottom of the axle locator slot's travel.

    If I could just buy a Monogram Sebring chassis, I'd do that!

    Any other ideas?

    * And has anyone tried to get those very accurate but fragile-looking inserts out of the MRRC wheels to reuse? I think they're photoetched, and they're glued into the plastic wheels - askew, of course. The BWA inserts are accurate for the earlier Chappys, but not for these -- the mesh pattern is different, and the 2F car had knockoffs. *
    Last edited by JML; 06-20-2009, 04:44 AM.
  • svanaken
    National Champion
    • Aug 2007
    • 5377

    #2
    To my knowledge, neither MRRC or Monogram provide inserts to their plastic wheels. That is the way the wheel half is molded. You have to cut them off and grind down the edges to get them to fit as inserts.

    Scott

    Comment

    • daisyslots
      Championship Contender
      • Apr 2006
      • 1439

      #3
      Is there enough surface area in the top of the axle supports for a set screw? The bottom set screws can be more to the center like the new slot.it chassis. Slot.it sells both short and long M2 set screws.

      Comment

      • JML
        Championship Contender
        • Jan 2006
        • 2171

        #4
        The Chappy wheels are not one-piece molded items. The wheel definitely has an insert glued into it. It's extraordinarily thin, and is inserted off-center and askew on every wheel! Plus there's a knockoff that is inserted from outside the insert and hot-melted on the inside (or glued to a retainer - I can't tell without opening it up).

        The axle slots are open at the top, just like the normal front and rear bushing slots, but narrower and elongated.

        These aren't my pictures; they're cropped from a review:

        Last edited by JML; 06-19-2009, 12:24 PM.

        Comment

        • Robert Livingston
          World Champion
          • Feb 2003
          • 16482

          #5
          I have a Porsche 910 which has a piece of 3/32" ID brass tubing that holds the axle. I just pushed it into the slots for the 3/32" axle, and glued it in place with Goop (a little on each upright). The vertical alignment was obtained by holding the car with both rear tires planted, and setting both front tires solidly on the setup block. The brass tubing was a ballpoint pen cartridge, and the OD is smaller than 1/8", so the fit is good. OD is .118", which happens to be 3mm.

          Comment

          • mmmoose1
            Championship Contender
            • Oct 2005
            • 2510

            #6
            I take a small piece of plastic angle and glue it to the floor of the chassis and open the hole up with a small round file. No fuss, no drill, lighter than brass tube choice. Ken

            Comment

            • Robert Livingston
              World Champion
              • Feb 2003
              • 16482

              #7
              I always build heavyweights. Did I mention the brass plate underneath? Rides like a Pullman.

              Comment

              • OneHotDog
                International Racer
                • Jan 2008
                • 549

                #8
                Originally posted by Robert Livingston View Post
                I have a Porsche 910 which has a piece of 3/32" ID brass tubing that holds the axle. I just pushed it into the slots for the 3/32" axle, and glued it in place with Goop (a little on each upright). The vertical alignment was obtained by holding the car with both rear tires planted, and setting both front tires solidly on the setup block. The brass tubing was a ballpoint pen cartridge, and the OD is smaller than 1/8", so the fit is good. OD is .118", which happens to be 3mm.

                LOL!!! Robert I always marvel at your improvisational fixes. Brilliant!

                Comment

                • Da Vols
                  Top Qualifier
                  • Mar 2004
                  • 4914

                  #9
                  The Monogram Shelby King Cobra (and am guessing the MRRC Lang Cooper too) has no bushings up front either.


                  Da Vol - Bruce

                  Comment

                  • acmost
                    Championship Contender
                    • Oct 2005
                    • 1943

                    #10
                    Originally posted by JML View Post
                    Any other ideas?
                    I did this...although this isn't the Monogram, I did do the same thing to a Monogram Chaparral. I just don't have a picture of it. I set it on the track in the slot, stuck the axle with wheels through & glued two Slot.it bushings to the inside. Works pretty well.
                    Last edited by acmost; 06-19-2009, 06:04 PM.

                    Comment

                    • Robert Livingston
                      World Champion
                      • Feb 2003
                      • 16482

                      #11
                      I have another one with a 1/16" steel axle, riding in a 3/32" brass tube, which fits the chassis slots well. Wheels are BWA with 1/16" holes. Body is a Strombecker Ferrari 365P.

                      Comment

                      • beejay7
                        Championship Contender
                        • Oct 2005
                        • 1439

                        #12
                        Like Robert....My 2F Chappy uses a section of 1/8th brass tube just glued to the axle shoulders...easy to setup, gets the guide to the correct depth and is strong.
                        My car uses Slot.it parts and the original MRRC front wheels complete....Rears are BWA 03's fitted with Ortman 9mm Ninco Classic tyres. If I remember correctly the MRRC Chappy inserts fitted the BWA wheel with no problem.....
                        My other 2F has a PCB inline chassis with BWA's all round complete with inserts.

                        Regards

                        Alan

                        Comment

                        • JML
                          Championship Contender
                          • Jan 2006
                          • 2171

                          #13
                          Originally posted by beejay7 View Post
                          Like Robert....My 2F Chappy uses a section of 1/8th brass tube just glued to the axle shoulders...easy to setup, gets the guide to the correct depth and is strong.
                          My car uses Slot.it parts and the original MRRC front wheels complete....Rears are BWA 03's fitted with Ortman 9mm Ninco Classic tyres. If I remember correctly the MRRC Chappy inserts fitted the BWA wheel with no problem.....
                          My other 2F has a PCB inline chassis with BWA's all round complete with inserts.

                          Regards

                          Alan
                          The 32002/04 wheels have a full .450" diameter insert area, while the 32001/03 have a .375" diameter insert area recessed into a .450" inner rim. The MRRC inserts are somewhere between the two (of course). I think the MRRC inserts would safely "sit" on the lip of inner rim on the 32001/03 wheels, although they wouldn't go into the wheel as deeply as in the plastic MRRC wheels.

                          Alan, how did you get the inserts out of the plastic wheels? I was going to slice them in half, then see if I could get the knockoff out without damage, and if I couldn't break the glue bond without damage to the insert, I was going to soak the glued insert and wheel in acetone to attack the glue and plastic (then repaint).

                          Robert, you don't happen to know what type of ballpoint refill you used, do you? Brass tube pen refills are less and less common as plastic is used more these days; brass Cross ballpoint refills have a 1/8" OD.
                          Last edited by JML; 06-20-2009, 06:13 AM.

                          Comment

                          • beejay7
                            Championship Contender
                            • Oct 2005
                            • 1439

                            #14
                            Alan, how did you get the inserts out of the plastic wheels? I was going to slice them in half, then see if I could get the knockoff out without damage, and if I couldn't break the glue bond without damage to the insert, I was going to soak the glued insert and wheel in acetone to attack the glue and plastic (then repaint).
                            Well one fell out when I took the wheel off!...and the other I pushed out with a thin axle....it wasn't glued in.
                            With hindsight I think I did cut down the insert to fit the BWA wheel...

                            Regards

                            Alan

                            Comment

                            • ProfFate
                              Champion Racer retired RIP
                              • Dec 2005
                              • 967

                              #15
                              Hi

                              curiously, I turn holes into vertical slots on cars that are NOT like the sebring! Slot cars are tripods defined by guide and rear wheels. The fronts go along for the ride, and are merely cosmetic.

                              Slop is good.

                              Fate

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