Tom Thumb Popular Mechanics 1970 Article help

oldrelics

oldrelics

New Member
#1
#1
I've ordered the mag but hasn't arrived yet and I need some help.
They say they used 5/8 tubing and a 5/8 bolt for the steering head but the diagram clearly shows a smaller hole for the bolt than the tube size. I can't make out the sizes they show in the artists rendering of the pic online. Anybody have a full size article they can check the specs for me?
 
oldrelics

oldrelics

New Member
#5
#5
I got them thanks, and there is a descrepancy= They show a 7/8 hole for the handlebars to go through the steering head bars. Also how do they get 5/8 pins in 5/8 tube? I don't think they used 5/8 tube at all.....
 
scootercat

scootercat

Active Member
#6
#6
Maybe the tube was measured by I.D. And the bolt is 5/8 O.D. I know pipe is sized by I.D. and tubing is by O.D.,just sayin'....Scootercat....
 
Last edited:
KustomKartKid

KustomKartKid

Administrator
#7
#7
I don't have these plans but tubing is aways measured by the O.D. ....the wall thickness determines the I.D. ...if it's a 5/8 bolt the tubing is likely 7/8 x .120
wall.......



.
 
Last edited:
Oldsalt

Oldsalt

Well-Known Member
#8
#8
The original plans [at least the ones I have] call for a 1/2" steering head bolt which would indicate a 3/4" OD X 1/8" wall tube which would [nominally] provide a 1/2" ID. I'm going to build mine using a 7/8" OD X 1/8" wall which would give a 5/8" ID as noted above by KustomKart. I plan an using 3/4" OD X 1/8" wall for the entire frame; but the forks and steering head will be 7/8" OD X 1/8" wall tube. The pic shows the triple clamps and the diameter of holes in them.
 
delray

delray

Well-Known Member
#10
#10
are these rims the same original style rims use on the the tom thumb bike? they look to have the same design and even the screw heads that hold the two piece rim together.
mini bike wheels | eBay

picture of the original rim design in the Popular Mechanics

 
Oldsalt

Oldsalt

Well-Known Member
#11
#11
They don't appear to be the same as the ones pictured in the original Popular Mechanics plans becaus they have 6, not 4 bolts. But that doesn't mean squat when it comes to a Tom Thumb....they were never manufactured for sale by anyone. You scraped together the parts that will work and need not care about "originality" because there is no 'stock' production model to copy. Wonder who [pretty sure an OldMiniBikes member] put them on eBay? I notice that the write-up said they would be fine for a Tom Thumb. Think about it; How many non-Old Minibike people would know anything about them? I am going to use 'Foam Filled' tires. They are regular China tires that you can get from Harbor Freight that have been injected with foam and will never go flat. Me...I'd tend to think that the tires and rims on eBay are going to have to be replated with zink or cad at the very least.
 
delray

delray

Well-Known Member
#12
#12
look again oldsalt, brochure and the wheels on ebay have 4 screw heads close to the center hub and 6 screw heads on the outer part of the rim. some of the screw heads look to be missing? and also has that small step in the rim where the 4 screw heads go in.:rolleyes: cool to have, if a person was looking to make it look just like the original bike did.
to bad Popular Mechanics had the photos in black and white. i wonder what color that was? lite yellow? can anybody here know how to color rise a picture?
 
Oldsalt

Oldsalt

Well-Known Member
#14
#14
delray said:
look again oldsalt, brochure and the wheels on ebay have 4 screw heads close to the center hub and 6 screw heads on the outer part of the rim. some of the screw heads look to be missing? and also has that small step in the rim where the 4 screw heads go in.:rolleyes: cool to have, if a person was looking to make it look just like the original bike did.
to bad Popular Mechanics had the photos in black and white. i wonder what color that was? lite yellow? can anybody here know how to color rise a picture?
Click to expand...
Ya...I did need to look again. In which case the eBay tires and wheels are worth buying. I guess my mindset is to avoid looking for hard to find parts. I keep thinking that not one person in 20 million would know the difference. but I gotta admit that them wheels would be cool to have.
 
Last edited:
Oldsalt

Oldsalt

Well-Known Member
#16
#16
Really nice wheels. I probably shouldn't be so cheap about the price of parts for a project that will consume a lot of hours to build. I'd still have to think about paying that much. That is better than 110 bucks [because of shipping] for a pair. But that are sure superior to the a HF stuff.
 
S

ScooterBoy

#17
#17
Nice set of frame components there OldSalt:thumbsup: I'm looking forward to seeing your finished product.
As for wheels, I used 4" Manco's on this one. I have a set of 4" GoPowers that I might put on it instead, or I'll just build another bike for the GoPowers? :shrug:
 
Oldsalt

Oldsalt

Well-Known Member
#19
#19
ScooterBoy said:
Nice set of frame components there OldSalt:thumbsup: I'm looking forward to seeing your finished product.
As for wheels, I used 4" Manco's on this one. I have a set of 4" GoPowers that I might put on it instead, or I'll just build another bike for the GoPowers? :shrug:
Click to expand...
With good reason you know I didn't make the components that were pictured! I hesitate to name the party that has the expensive industrial equipment to make such precision parts. Heck, if I did a lot of people would be sending you PMs. I just cannot begin the project right now. With the build-off coming up it is tempting to jump on it...but it can't be done right now. It is going to be a Tom Thumb with proper parts but with a hot-rod engine. I've looked for a reasonably priced Olsen-Rice engine for a couple of years...so I gave up on a 'stock' engine.
 
delray

delray

Well-Known Member
#20
#20
oldsalt, what kind of motor where you going to use? if not a Olsen-Rice.
i wonder if a tecumseh II would work or too new looking or too big maybe?
 
You must log in or register to reply here.
Top