Thanks, I'm pretty sure that I have one. I'll take a look
EM
EM
Building a Pre-Add BRM
The combination of an apparent high level of interest in Mac Pinches Pre-Add bdies as decribed in "News" and the recent arrival of some of Mac's new laser cut chassis has prompted me to start another project along side the W154/Patto chassis that is ongoing.
Thinking that there might be some interest in this project, I am going to document it in photos and (hopefully) brief text as it progress.
These will be a series of "real time" progress reports, not a "how to" since what I describe in one post may well be reversed in the next when I discover that it didn't work! I'll try to keep a rough log of time and cost.
The bits and pieces:
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In no particular order: the body molding, driver, vac-formed screen and metal castings for the steering wheel, exhausts and filler cap (all part of the body kit) There are actually two chassis in the picture - on the lower right the laser cut chassis as supplied and spread about the middle, the parts after cutting and removal of the webs. The rear axle carriers/rear motor mount are "stuck" together. The fit of the parts is so good that the assembly is stable without soldering! Also in the picture is a guide and guide shaft bearing. One of the first things that I do with any commercial chassis is to try and figure out what guide shaft fits the hole. This is of particular interest for laser cut steel chassis because my experience is that these holes can oly be enlarged with some difficulty, the steel being very hard. In this case, the TSRF guide made for conversion of plastic chassis is a perfect fit and, on preliminary examination, to be short enough so that it will not extend beyond the front of the car (important for some rules)
Now let's do the numbers: A quick Google search yielded:
http://8w.forix.com/brmp15.html
LOA: 158"
Width 56"
Height 35"
WB 98"
Wheels and tires: 5.25 X 18 front, 7.00 X 17 rear
If I believe my digital caliper, the wheelbase is spot on and the length is very close (perhaps 0.10" too short, but, the body that Mac has modeled differs from the one pictured on the site so I'm going to call it perfect!
A listing of tire dimensions for Dunlop Vintage Series tires yields:
7.00 X 17 30.2" diameter
5.50 X 18 30.1" and 5.00 X 19 29.6" so I'm calling 5.25 X 18 as 29.7"
This translates into 0.94" rear tires and , rounded to /100s, the same at the front.
Quick dimension check: The distace from the center of the rear axle carrier to the bottom of the chassis is about 0.288" If we subtract that from the radius of the proposed rear tire, 0.47", we are left with 0.18", plenty of room to add a weight pan and still meet a 0.125" ground clearance rule.
Second check - height is listed @ 35" or 1.1" in 1/32 scale. Knowing the axle height we can then check the body to see where the axle would be to give us that height in the finished car - and it turns out to be exacltly where Mac has placed the top of the rear axle slots!
Little worry (postponed until the initial chassis assembly is done and a motor fitted) - the fit between the top of the motor and the dash is the limiting factor for positioning the body on the chassis and, at first glance, it is a problem. The decision will be: can enough be ground off the bottom of the dash to accomodate the motor or will the dimensions dictate a front motor placement (and, in the latter case, isn't it nice that the chassis kit includes twoadditional motor mounts!)
An issue which has arisen long before its time: decoration: I am not really enamored of the peculiar diseased liver green that was chosen for these cars! (I recognize that there may have been budget constraints but did they really have to use paint left over from the redecoration of the railway station loos?) Any suggestions as to alternate correct liveries will be appreciated. I reserve the right to assign the car to Ecurie Martini and since this organization (long predating the red, white and blue "Martini" sponsorships) is a Belgian/American consortium, I'll paint it yellow!
Time so far, hands on and on the net, about 2 hours - parts @ current exchange, about $50
Next steps: chassis assembly, motor, axles & gears
EM
Thinking that there might be some interest in this project, I am going to document it in photos and (hopefully) brief text as it progress.
These will be a series of "real time" progress reports, not a "how to" since what I describe in one post may well be reversed in the next when I discover that it didn't work! I'll try to keep a rough log of time and cost.
The bits and pieces:
In no particular order: the body molding, driver, vac-formed screen and metal castings for the steering wheel, exhausts and filler cap (all part of the body kit) There are actually two chassis in the picture - on the lower right the laser cut chassis as supplied and spread about the middle, the parts after cutting and removal of the webs. The rear axle carriers/rear motor mount are "stuck" together. The fit of the parts is so good that the assembly is stable without soldering! Also in the picture is a guide and guide shaft bearing. One of the first things that I do with any commercial chassis is to try and figure out what guide shaft fits the hole. This is of particular interest for laser cut steel chassis because my experience is that these holes can oly be enlarged with some difficulty, the steel being very hard. In this case, the TSRF guide made for conversion of plastic chassis is a perfect fit and, on preliminary examination, to be short enough so that it will not extend beyond the front of the car (important for some rules)
Now let's do the numbers: A quick Google search yielded:
http://8w.forix.com/brmp15.html
LOA: 158"
Width 56"
Height 35"
WB 98"
Wheels and tires: 5.25 X 18 front, 7.00 X 17 rear
If I believe my digital caliper, the wheelbase is spot on and the length is very close (perhaps 0.10" too short, but, the body that Mac has modeled differs from the one pictured on the site so I'm going to call it perfect!
A listing of tire dimensions for Dunlop Vintage Series tires yields:
7.00 X 17 30.2" diameter
5.50 X 18 30.1" and 5.00 X 19 29.6" so I'm calling 5.25 X 18 as 29.7"
This translates into 0.94" rear tires and , rounded to /100s, the same at the front.
Quick dimension check: The distace from the center of the rear axle carrier to the bottom of the chassis is about 0.288" If we subtract that from the radius of the proposed rear tire, 0.47", we are left with 0.18", plenty of room to add a weight pan and still meet a 0.125" ground clearance rule.
Second check - height is listed @ 35" or 1.1" in 1/32 scale. Knowing the axle height we can then check the body to see where the axle would be to give us that height in the finished car - and it turns out to be exacltly where Mac has placed the top of the rear axle slots!
Little worry (postponed until the initial chassis assembly is done and a motor fitted) - the fit between the top of the motor and the dash is the limiting factor for positioning the body on the chassis and, at first glance, it is a problem. The decision will be: can enough be ground off the bottom of the dash to accomodate the motor or will the dimensions dictate a front motor placement (and, in the latter case, isn't it nice that the chassis kit includes twoadditional motor mounts!)
An issue which has arisen long before its time: decoration: I am not really enamored of the peculiar diseased liver green that was chosen for these cars! (I recognize that there may have been budget constraints but did they really have to use paint left over from the redecoration of the railway station loos?) Any suggestions as to alternate correct liveries will be appreciated. I reserve the right to assign the car to Ecurie Martini and since this organization (long predating the red, white and blue "Martini" sponsorships) is a Belgian/American consortium, I'll paint it yellow!
Time so far, hands on and on the net, about 2 hours - parts @ current exchange, about $50
Next steps: chassis assembly, motor, axles & gears
EM
21 - 40 of 82 Posts
2
QUOTE If anyone went out and ordered parts on the basis of my last post - I warned you at the outset
Wha? ...and I've got 25 gallons of pale green duck egg blue (aka "sky type S") on the way too
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Great entertainment EM - Thank you! Keep it coming
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Wha? ...and I've got 25 gallons of pale green duck egg blue (aka "sky type S") on the way too
Great entertainment EM - Thank you! Keep it coming
4
Almost rolling: The next logical step was wheels and tires - I like to have those set before I do the body mounts - measuring and calculating is fine but, in the end, I want to see what it looks like!
I decided to take a shortcut and modify some BWA wheels I had on hand. Here's the before and after:
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For those interested in the process: I mount a wheel on a piece of 3/32 drill blank and chuck it in a 3/32 collet then face off the front back to the edge of the rib. The depression for the tire is then machined - I used a 60 degree indexable carbide tool perpendicular to the work giving me a 30 degree angle on either side. The wheel front is then hogged out with a 5/16" end mill mounted in the tailstock (could go larger but that is all the chuck will handle. The recess is then finished with a boring bar to a 0.505" ID to suit cut-down Ninco wires as inserts. (I run the boring bar in until I hit the set screw - this messes up the screw and threaded hole but this is not a problem since I subsequently cross-drill the brake drum to take a 1-72 set screw. This allows me to glue the tire on and true it without worrying about access to the mounting screw) The wheel is removed and the axle pushed thru to allow it to be mounted backwards. The rear section was turned down to 0.44" - to make a 14" brake drum. there was a fair amount of back and forth on the dimesions of the wheel, mounting and unmounting various tires until I got the "look" that I wanted:
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From left to right: two rear wheels with Ortman 1/32 tires mounted, one cndidate front with and EJ's #15 tire and at far right, the same wheel with a 3/16" cross section O-ring mounted and grond down to provide a flat tread ( More about the O-rings later)
The difference in width is apparent:
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Again, left to right: Ortmann, EJ (rounded), O-ring
And finally -
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AlFin drums, of course!
The O rings are an experiment - perhaps a bit too rounded for anything later than about 1950 but pretty good earlier than that and, I think, better than most choices for 30's and earlier. They are available in a vast range of cross sections and diameters in fractional inch, decimal inch and metric measurements. I have no idea if they offer any traction at all - not a concern for fronts - but I shall see if they can be coated with RTV silicone such as Permatex Form-A-Gasket to serve as rears as well. In addition to the size range, they offer another advantage - they are about $6.00 for a bag of 50!
Now that I have wheel dimensions, I can cut the axles and front bearing tube to length and get things rolling.
Time - about 2 hours to figure out the first wheel and tire set-up - 20 minutes each to do the rest
Costs: 2 pr BWA wheels @ $6.50/pr, set of Ninco wheels - about $5.00, Ortmann & EJs tires - $10 - axles $1.00 (I buy ground drill blanks in lots of 25 from an industrial supply house)
Looks like it's going to be about a $90-$100 slot car
EM
I decided to take a shortcut and modify some BWA wheels I had on hand. Here's the before and after:
For those interested in the process: I mount a wheel on a piece of 3/32 drill blank and chuck it in a 3/32 collet then face off the front back to the edge of the rib. The depression for the tire is then machined - I used a 60 degree indexable carbide tool perpendicular to the work giving me a 30 degree angle on either side. The wheel front is then hogged out with a 5/16" end mill mounted in the tailstock (could go larger but that is all the chuck will handle. The recess is then finished with a boring bar to a 0.505" ID to suit cut-down Ninco wires as inserts. (I run the boring bar in until I hit the set screw - this messes up the screw and threaded hole but this is not a problem since I subsequently cross-drill the brake drum to take a 1-72 set screw. This allows me to glue the tire on and true it without worrying about access to the mounting screw) The wheel is removed and the axle pushed thru to allow it to be mounted backwards. The rear section was turned down to 0.44" - to make a 14" brake drum. there was a fair amount of back and forth on the dimesions of the wheel, mounting and unmounting various tires until I got the "look" that I wanted:
From left to right: two rear wheels with Ortman 1/32 tires mounted, one cndidate front with and EJ's #15 tire and at far right, the same wheel with a 3/16" cross section O-ring mounted and grond down to provide a flat tread ( More about the O-rings later)
The difference in width is apparent:
Again, left to right: Ortmann, EJ (rounded), O-ring
And finally -
AlFin drums, of course!
The O rings are an experiment - perhaps a bit too rounded for anything later than about 1950 but pretty good earlier than that and, I think, better than most choices for 30's and earlier. They are available in a vast range of cross sections and diameters in fractional inch, decimal inch and metric measurements. I have no idea if they offer any traction at all - not a concern for fronts - but I shall see if they can be coated with RTV silicone such as Permatex Form-A-Gasket to serve as rears as well. In addition to the size range, they offer another advantage - they are about $6.00 for a bag of 50!
Now that I have wheel dimensions, I can cut the axles and front bearing tube to length and get things rolling.
Time - about 2 hours to figure out the first wheel and tire set-up - 20 minutes each to do the rest
Costs: 2 pr BWA wheels @ $6.50/pr, set of Ninco wheels - about $5.00, Ortmann & EJs tires - $10 - axles $1.00 (I buy ground drill blanks in lots of 25 from an industrial supply house)
Looks like it's going to be about a $90-$100 slot car
EM
G
I am really looking forward to see the finished car. Most interesting.
RR
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RR
Hi EM,
I've just started to put one of my monoposto chassis together. I want to use trailing guides from Patto They have 3/16" posts. You're right about the steel being hard to drill and there's not much metal to spare. i'm just about to start cutting the chasssis into its component parts. I'm expecting to go through a lot of cut off discs.
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John
I've just started to put one of my monoposto chassis together. I want to use trailing guides from Patto They have 3/16" posts. You're right about the steel being hard to drill and there's not much metal to spare. i'm just about to start cutting the chasssis into its component parts. I'm expecting to go through a lot of cut off discs.
John
2
Speaking of Wire Wheels and large dia tires.Here's my latest wire insert.The knockoff comes molded in,so you won't lose it in a shunt.
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Martini
Very nice work!
Why not bring it to the NLondon retro in May?
[oneofwos]
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Very nice work!
Why not bring it to the NLondon retro in May?
[oneofwos]
Martini
Never really gave it a thought that you might be from across the water!
It's on the 29th May [Saturday], if you happen to be over then please come and visit you would be most wellcome.
[oneofwos]
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Never really gave it a thought that you might be from across the water!
It's on the 29th May [Saturday], if you happen to be over then please come and visit you would be most wellcome.
[oneofwos]
2
Awesome piece of history to be a part of, EM!!
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Thanks for sharing it!
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Thanks for sharing it!
4
QUOTE Several weeks later I received a package containing two motors with integral brass axle carriers and pinion and contrate gears and having the brush gear mounted on the side of the motor (as in the DC62A/B). He asked for my evaluation. I believe that these were the first slot car motors that Pittman made. They were used to power my entrants. Like the bodies, they survive today.
Well,now we know at least one guilty party we can Blame Eh!
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Well,now we know at least one guilty party we can Blame Eh!
QUOTE (howmet tx @ 8 Mar 2004, 06:16 PM)Which old sod are you referring to, Prof? I didn't know we were allowed to use that sort of language 'ere......
I think he means the UK...Great Britain...this SEPTIC isle
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Mark.
I think he means the UK...Great Britain...this SEPTIC isle
Mark.
21 - 40 of 82 Posts
