M113 design progress

[Modena]

I will be building an M113 as my next vehicle and have been playing on
and off with designing and now have a fair bit of measurement detail
on drivetrain components. I have found it immensely helpful to the
design process to draw components to exact size in sketchup, such as
bearing housings and wheels, it really helps with visualizing and
determining available space for bolt heads and the like, rather
important where tolerances are small.

Here are some pics of the external suspension components, springs will
be torsion bars on the inside. The vehicle body, drivetrain and
suspension will be all steel. The bearing housings are steel with
bronze bushings, 12mm for swingarms and 16mm for driveshafts. The
idler will be on a small swingarm, with a turnbuckle for track tension
adjustment.

[Steve Tyng]

Nice Sketchup work. I've just ordered Rhino so maybe someday I'll be
able to do stuff like this.

Steve Tyng

>  Drivetrain 5.jpg
> 358KViewDownload
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>  Drivetrain 4.jpg
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>  Drivetrain 3.jpg
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>  Drivetrain 2.jpg
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>  Drivetrain 1.jpg
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>  Drivetrain 6.jpg
> 422KViewDownload

[Doug Conn]

Yeah, really good Sketchup work. I tried Sketchup but my results were not
nearly as impressive. How did you go about learning the software ?

Thanks,
Doug

[Modena]

I just started using it, when I need to do something that I dont know
how to do I just google it, because it's free there is TONNES of vids
on youtube, forums and the like on every little detail of Sketchup

[Clark Ward Jr]

I bought Alibre Design Professional, it seems to be more intuitive
than Sketchup was for me. But then, Sketchup is free, and I expect a
purchased CAD program to be more intuitive for me than a free product.
(Yes, I've seen the great work some people have done in Sketchup,
this is just my feelings on it; others are probably better with
Sketchup than I...) Of course, I use Alibre for other things, too,
and it does things I want that Sketchup can't. What Mod said above is
true; lots of Sketchup videos online for learning. Part of me
doesn't like keeping my design stuff where Google can access it at
will, though, they're more invasive than Microsoft ever was (/will
be?)

--
Clark in Georgia, Commissar of the Red Banner Southern Fleet
"We will pass through the American patrols, past their sonar nets, and
lay off their largest city, and listen to their rock and roll... while
we conduct missile drills."

[Frank Pittelli]

Modena wrote:
> Here are some pics of the external suspension components, springs will

> be torsion bars on the inside. [Design drawings snipped]

As a long-term member and leader of the computer science world, I hereby
apologize to everyone in the R/C world for my software colleagues who
invent, develop, promote and otherwise distribute software that makes
people believe that drawing something on the computer is better than
sketching a few drawings by hand. Sure, the CAD software my colleagues
have fostered is "neat", "fun to use" and can, after a mere 30 years,
almost look like real things, but alas, the results are still simply
drawings and pictures that don't come anywhere close to reality.

I also hereby apologize to everyone in the R/C world for my colleagues
who invent, develop, promote and otherwise distribute software that
makes people believe that the output of the aforementioned CAD software
can actually be uploaded to even more magical CNC software that makes
people think they can simply push a button from their virtual world and
make real things in the real world. Sure, the CNC software my
colleagues have fostered is "neat", "fun to use" and can, after a mere
30 years, produce relatively simple parts, but alas, the results are
still simply parts that must be put together to make something useful
(unless you're really into key-chains made from old CDs).

Sorry. We simply didn't know the software tools made to streamline
mass-produced products would cause the downfall of hobby workshops
around the world. As the older generation of tinkerers retire and die
off, their legacy of haunted-house gadgets, pumpkin chunkers, strange
Christmas displays, ugly lamps, weird vehicles, R/C everything, and good
ole fashioned worthless novelties will apparently be replaced by lots of
pictures on the Internet of things somebody thought about building, but
never actually did.

Frank "Designs Are Only 1/50th Of The Process" Pittelli

[Mike Mane]

Nice job on Sketchup! You must be doing something different then me
because I have never been able to draw a good circle on Sketchup.
Whenever I use the tool it comes out like a decagon or something. In
other words, the sides are visible. Did I miss something?

Message sent by way of mobile device

> <Drivetrain 5.jpg>
> <Drivetrain 4.jpg>
> <Drivetrain 3.jpg>
> <Drivetrain 2.jpg>
> <Drivetrain 1.jpg>
> <Drivetrain 6.jpg>

[Modena]

draw your circle, setting radius either by mousing, or as I do, type
in "50mm" for 50 millimeters and press ENTER, then type "100s" and
ENTER for 100 sides :)

eg draw circle, 5mm + ENTER, 6s + ENTER will give you a hex head
polygon 5mm in radius

I have found at the scale we work at 100 sides is ample for a circle.

[?]

That looks awesome! Were you planning on building her an the apc or
one of the armed variants?

> > > <Drivetrain 6.jpg>- Hide quoted text -
>
> - Show quoted text -

[Modena]

APC for now

[callum.kin...@googlemail.com]

Want to get picky and very high poly you could do 360 sides

[callum.kin...@googlemail.com]

Edit. I find 10 is enough anyway

On Oct 18, 8:07 am, Modena <b...@holnet.net> wrote:

[Modena]

and here is what the tracks will look like;

[Mike Mane]

Holy crap, nice job! How will you fold the tracks over the top of the
wheel system? (if you are planning to)

—Mike M

Message sent by way of mobile device

On Oct 18, 2009, at 7:12 AM, Modena <b...@holnet.net> wrote:

> and here is what the tracks will look like;
>
>
> >

> <Drivetrain with track 3.jpg>
> <Drivetrain with track 1.jpg>
> <Drivetrain with track 2.jpg>

[Modena]

just rotate a section of track at a time

[Modena]

after many, many hours on the computer and a visit to the friendly
neighborhood laser cutter, the vision is becoming a reality...

these parts were laser-cut straight from cad files which were saved
from sketchup

Laser-Cut parts

[Doug Conn]

That is just beautiful work. I'm especially interested to see the tracks
completed.

Would you feel comfortable telling us the costs of this work ? I'm curious
and I bet many of our other members are, too.

Thanks,
Doug


-----Original Message-----
From: rctank...@googlegroups.com [mailto:rctank...@googlegroups.com]
On Behalf Of Modena
Sent: Tuesday, October 27, 2009 7:12 AM
To: rctank...@googlegroups.com
Subject: [TANKS] Re: M113 design progress

[Modena]

sure thing Doug;

sprocket $5.85 each
idler $6.65 each

guide tooth $0.28 each (I need 150)
track link $0.18 each (need 300)
track lug $0.25 each (need 300)

so all of that was $221

these are expensive tracks, the rubber was $80 for strips of 20mm x
12mm x 1 meter (8 strips)

plus high-tensile cap screws are not cheap.

[Odyssey...@aol.com]

That's just impressive!

 

Chris,
Odyssey Slipways

[Odyssey...@aol.com]

In a message dated 10/27/2009 5:27:31 P.M. Eastern Daylight Time, b...@holnet.net writes:

sure thing Doug;

sprocket $5.85 each
idler $6.65 each

guide tooth $0.28 each (I need 150)
track link $0.18 each (need 300)
track lug $0.25 each (need 300)

so all of that was $221

these are expensive tracks, the rubber was $80 for strips of 20mm x
12mm x 1 meter (8 strips)

plus high-tensile cap screws are not cheap.

i think a lot of people would be willing to shell that out for a nice set of tracks like you have there!

 

(you said your going to do a Tiger next, right)

 

Chris,
Odyssey Slipways

[Doug Conn]

Someone laser cut that sprocket for six bucks !?!?!

That's it. I'm moving.

[Ben Holko]

Yes. I had three quotes, that was cheapest, most expensive was about $15 for the sprocket.

________________________________

[Doug Conn]

That's amazing to me.



Does anybody know of any shop in the US that has rates like the ones Ben
quoted ?



- Doug

From: rctank...@googlegroups.com [mailto:rctank...@googlegroups.com]
On Behalf Of Ben Holko
Sent: Tuesday, October 27, 2009 6:17 PM
To: rctank...@googlegroups.com
Subject: [TANKS] Re: M113 design progress

Yes. I had three quotes, that was cheapest, most expensive was about $15 for
the sprocket.



_____

[George Mastoras]

That's probably not the norm for laser cutting prices.
This laser cutting shop was put on to me from the person doing some lathing
for me.

Looked around for a while and was going to go somewhere else and pay more
(close to double) but was thankfully informed of this mob.

Usually others wanted 80 - 100 dollars minimum, these guys wanted 50
dollars for a minimum and their turnaround is usually between 2-5 days.
Being local is also a bonus, funny thing is the dxf files get sent
interstate and then get done locally.
Their philosophy is if they take the small jobs they hopefully will get the
big jobs as well. These prices are probably going to be hard to beat.

[Gregory Pwneror]

How much does that LASER cutting cost and how is the cost measured? (eg length of cut total, time to cut etc.)

-Gregory

[Ben Holko]

go back a couple of posts and you will see the cost.

I might add, those costs include the cost of the material (they supplied the steel, beat that).

they measure cost on the material obviously, unless you supply your own, and the length of time that your job occupies the machine. The formula is unknown to us mere mortals and would no doubt be their trade secret, but that is how they calculate it.

Ben


________________________________

[Steve Tyng]

You can always try http://www.emachineshop.com for a quote.

Steve

On Oct 27, 11:30 pm, Gregory Pwneror <sockles...@gmail.com> wrote:
> How much does that LASER cutting cost and how is the cost measured? (eg
> length of cut total, time to cut etc.)
>
> -Gregory
>
> On Wed, Oct 28, 2009 at 1:10 PM, George Mastoras <id...@optusnet.com.au>wrote:
>
>
>
> > That's probably not the norm for laser cutting prices.
> > This laser cutting shop was put on to me from the person doing some lathing
> > for me.
>
> > Looked around for a while and was going to go somewhere else and pay more
> > (close to double) but was thankfully informed of this mob.
>
> >  Usually others wanted 80 - 100 dollars minimum, these guys wanted 50
> > dollars for a minimum and their turnaround is usually between 2-5 days.
> >  Being local is also a bonus, funny thing is the dxf files get sent
> > interstate and then get done locally.
> > Their philosophy is if they take the small jobs they hopefully will get the
> > big jobs as well. These prices are probably going to be hard to beat.
>

[Doug Conn]

I threw together a quick eMachineShop part to compare this pricing. It
should be roughly similar to Ben's idler. It's 4" diameter, .25" thick 1018
steel with a few holes inside. Here's the eMachineShop pricing:

4 pieces: $53/ea
25 pieces: $21/ea
100 pieces: $14/ea

- Doug

-----Original Message-----
From: rctank...@googlegroups.com [mailto:rctank...@googlegroups.com]
On Behalf Of Steve Tyng
Sent: Wednesday, October 28, 2009 7:08 AM
To: R/C Tank Combat
Subject: [TANKS] Re: M113 design progress

You can always try http://www.emachineshop.com for a quote.

Steve

----~----~------~--~---

[Thomas Lum]

The first tank to $30,000 wins!

[callum.kin...@googlemail.com]

Well i havent noticed anything in the rules about no turbine engines.
ONly internal combustion. No doubt someones going to correct that soon
or i simply missed it but they can be pretty damn expensive. Seen some
with generators built in so you want an expensive tank. Get some
turbines instead of batteries and run them to generate power for some
very expensive motors. And gold plate the internals of your tank.
EAsily hit $30000 dollars. Especially if you were to use platinum
instead of steel for your treads

[Clark Ward Jr]

Sadly, bubba, turbine engines are internal combustion engines.

--
Clark in Georgia, Commissar of the Red Banner Southern Fleet
"We will pass through the American patrols, past their sonar nets, and
lay off their largest city, and listen to their rock and roll... while
we conduct missile drills."

[Clark Ward Jr]

Although nuclear is legal, as are radioisotope thermoelectric
generators (RTGs). Easily get a tank into the millions (Physics note:
I'm pretty certain you can't get enough fissile material into
something the size of a 1/6 scale tank, with all the piping, pumps,
steam generators, and turbine generators, and still have enough
fissiles to get critical. So no nuclear plant.) (But RTGs are
possible).

[Steve Tyng]

The Cromwell is for sale. Price: $30,000.00 US.


Steve "Give me a call, lets talk" Tyng

On Oct 28, 11:17 am, Thomas Lum <t...@mac.com> wrote:
> The first tank to $30,000 wins!
>

> On Wednesday, October 28, 2009, at 11:13AM, "Doug Conn" <dwconn...@comcast.net> wrote:
>
> >I threw together a quick eMachineShop part to compare this pricing. It
> >should be roughly similar to Ben's idler. It's 4" diameter, .25" thick 1018
> >steel with a few holes inside. Here's the eMachineShop pricing:
>
> >4 pieces: $53/ea
> >25 pieces: $21/ea
> >100 pieces: $14/ea
>
> >    - Doug
>
> >-----Original Message-----
> >From: rctank...@googlegroups.com [mailto:rctank...@googlegroups.com]
> >On Behalf Of Steve Tyng
> >Sent: Wednesday, October 28, 2009 7:08 AM
> >To: R/C Tank Combat
> >Subject: [TANKS] Re: M113 design progress
>

[Clark Ward Jr]

>
> The Cromwell is for sale.  Price:  $30,000.00 US.
>
>
> Steve "Give me a call, lets talk"  Tyng
>

Only if it still has the oscillation overthruster ;)

--
Clark in Georgia, Blue Blaze Irregular #602

[Bill Hamilton]

How about $10 and some pocket lint?

-Bill Hamilton

[George Mastoras]

If you accept pocket lint, would you also accept navel lint?

George

[Ben Holko]

Its been a busy day, chopped up all the rubber strips, I had it supplied 12mm thick and 20mm wide, in 1 meter lengths. Sliced and diced into 26mm long blocks, using an extendable stanley knife.

Then each block gets marked using a link as a guide, with a cordless drill.

Then each block gets drilled in a bench drill

Then each block gets angular corners cut with a stanley knife

Then the track can go together

These tracks are awesome, but they're very labor intensive.

Today I cut all the rubber, then processed enough raw blocks to make about 3 feet of track, all up spent about 6-7 hours on it so far. Tomorrow I should get both tracks finished, although my back hurts from sitting at the bench for so long already!

> 5mm thick steel sprocket
>
>
>
>
> 8mm thick idler wheel
>
>
>
>
>
> track components, 2mm thick plate, 3mm thick guide tooth and 5mm thick  
> sprocket-engagement lug, M4 high-tensile bolts.
>
>
>
>
> the track design is a GMTS (George Mastoras Track System :), the  
> spaces either side of the guide tooth will have a rubber block with  
> holes drilled for the bolts to pass thorough. It will be clearer with  
> more pics after this weekend :)
>
>
> Ben

>
>
> On 18/10/2009, at 11:12 PM, Modena wrote:
>

[Pete Curran]

Ben

Those tracks look awesome, your bucket will look great riding around on those

 

 

Pete

 

From: rctank...@googlegroups.com [mailto:rctank...@googlegroups.com] On Behalf Of Ben Holko
Sent: Saturday, 31 October 2009 18:52
To: rctank...@googlegroups.com
Subject: [TANKS] Re: M113 design progress

 

Its been a busy day, chopped up all the rubber strips, I had it supplied 12mm thick and 20mm wide, in 1 meter lengths. Sliced and diced into 26mm long blocks, using an extendable stanley knife.

[Clark Ward Jr]

Inspiring work, man, simply inspiring.

--
Clark in Georgia

[Bill Hamilton]

On Sat, Oct 31, 2009 at 2:51 AM, Ben Holko <b...@holnet.net> wrote:
>
> Its been a busy day, chopped up all the rubber strips, I had it supplied 12mm thick and 20mm wide, in 1 meter lengths. Sliced and diced into 26mm long blocks, using an extendable stanley knife.
>
> Then each block gets marked using a link as a guide, with a cordless drill.
>
> Then each block gets drilled in a bench drill

Very nice, but save yourself some work and frustration, make a jig for
the pads rather than doing the drilling freehand. Screw two pieces of
wood together at right angles. Using one of the links, position it on
the drill press table so the vertical is the right distance from the
drill bit, and clamp it in place. Put a rubber block in place, and
with the link, align the block for a hole, and draw a line on the
vertical. Align for the second hole, and draw a second line on the
vertical, on the same side of the block. Clamp block so it's aligned
on a line, drill, move it to the other line, drill again, done.

If you're absolutely certain that the pads are the right length, you
draw a single line and screw a piece of wood aligned with it. Drill
one hole, rotate the pad 180 degrees (keep the same pad face against
the vertical), drill the second.

These tracks look like they'll be awesome, I can't wait to see them completed.

--
-Bill Hamilton

[Frank Pittelli]

On Oct 31, 9:06 am, Bill Hamilton <billw...@gmail.com> wrote:
> If you're absolutely certain that the pads are the right length, you
> draw a single line and screw a piece of wood aligned with it.  Drill
> one hole, rotate the pad 180 degrees (keep the same pad face against
> the vertical), drill the second.

That's a good way to ruin hundreds of parts!!! Since parts are almost
never exactly the correct length, the "drill from both edges" approach
will almost always result in the wrong spacing between the holes.
That method ensures that the spacing from "both edges" is the same,
but in this case he needs the "spacing between holes" to be the same.
In that case, you need to use a different jig. Specifically, use a
vertical guide on one side of the jig to drill the first hole at the
desired location just like in the method you described. We'll call
that the "front-edge" of the pad. Then, flip the pad over, placing
the other face against the jig and place the first hole over a
"locating pin" which is exactly the desired distance from the drill
bit. Now, the second hole will be the right distance from the first
and any slop in the size of the pad will only be on the "back-edge".
If the alignment pin is tall enough, it will also ensure that the
holes are "parallel" through the part.

Frank "Ruined Plenty Of Parts Myself" Pittelli

[Odyssey...@aol.com]

damn! I want one of them!

 

i do have one little question - what stops the rubber pads from binding up on the bolts? are the pads mounted onto the threaded areas of the bolt? (okay, i had 2 questions)

 

Chris,
Odyssey Slipways

[Odyssey...@aol.com]

i like the way he cut the blocks the first time, all nice and clean looking - like they came from the warehouse that way

 

Chris,
Odyssey Slipways

[Derek Engelhaupt]

Ben,

The tracks I started using my hollow pin chain were originally going to be built in a
similar way, but I couldn't find rubber sheet like that.  Do you mind telling me where
you got the rubber and how thick it is?  Thanks.

Derek
T065

[George Mastoras]

The rubber is the easiest part of this track design and can be done very quickly.
The parts in these photos are some spare rubber blocks from the leclerc.
One side of that tank has single blocks and the other has this method more similar to a band track, This was the original design of the track but has changed over the years on different models and experimented on.
 
Bens had a factory tour of my workshop so you should also know there is this variation of using the rubber to consider. If you wanted to use this track design on a half track, this is how you would do it.
 
The second photo shows an almost ready to drill jig block, I just attached a paper printout of the hole locations to the jig and tighten the assembly. Move to drill press and drill.
When I did these on the Leclerc I counted myself and it averaged 25 seconds a hole.
 
Rubber is very forgiving so a few errors don’t matter really, not worth complicating it.
Next photo shows the rubber strips after being cut with basically just an angle grinder, strips are joined in pairs and cut in pairs. These are all spares as it was that easy to make these. Many ways to make these.
 
Leaving the small rubber contact between the blocks does give the track an advantage, it might look more accurate to have blocks but what you see in the picture will definitely give you a better track in the long run, blocks probably look better but just letting you know.
 
The rubber used on these tracks, Leclerc, Bens, My M41 where purchased from just a local rubber shop called Clarke rubber, a generic rubber store in Australia. You have to ask them to get it cut, so its an order job. The pieces we got where a meter long.
 
Final photo is a sneak peak at a variation of the track am working on for the bulldog.
The rubber in this photo is exactly the same that Ben is using so this track will be a little wider due to the steel pads. You can see the bolts here, some are too long but you can see the shaft and thread, it all just holds together rather well.

The bulldog track is a little tricky but am happy with the triangular metal contact area.
Next evolution of this track is to add more metal contact with the ground so have started in that direction.
The rubber has just been cut to bend here as am finishing the cleat so this is just an early test piece.

 
George Mastoras

Odyssey Slipways <http://hometown.aol.com/odysseyslipways/index.html>

[Bill Hamilton]

Yes, that's why I said "if".

-Bill Hamilton

On Oct 31, 2009, at 9:50 AM, Frank Pittelli <frank.p...@gmail.com>
wrote:

[Ben Holko]

Like George said it came from a shop here called Clarke Rubber, they mostly stock pool stuff, outdoor furniture etc, but have a selection of neoprene and foam rubbers and foam, however this stuff they had to order in.

It is 12mm thick, and we had it supplied in 20mm wide strips 1 meter long.

Ben

 
Chris,
Odyssey Slipways <http://hometown.aol.com/odysseyslipways/index.html>

[Ben Holko]

Chris,

The bolts do not pivot inside the rubber – the holes in the rubber were drilled with a 4.5mm bit, bolts are 4mm. However due to the distortion in the rubber when you drill it, it is still a push-fit (small finger force) to push the bolt through the rubber. The hinge effect comes from the lugs pivoting on the bolts – the locknuts are done up to the point where everything touches, but is still just free to pivot.

Ben

On 1/11/09 2:03 AM, "Odyssey...@aol.com" <Odyssey...@aol.com> wrote:

Chris,
Odyssey Slipways <http://hometown.aol.com/odysseyslipways/index.html>

[Ben Holko]

Due to the blocks being measured by hand and then cut by hand with a razor blade, they have nice sharp edges, but are probably about 0.2mm - 0.5mm in variance, which is why I use a track link as the jig to mark the holes. The variance doesn’t cause a problem because the rubber is forgiving if you’re out by 0.5mm the rubber will stretch when you pass the bolt through it.

BTW the track link and lug are 10mm wide, the rubber is 12mm thick. This is by design, so I have 2mm of rubber on the outside face of the track, so when on hard surfaces there will not be any metal in contact with the ground. On soft surfaces with at least 2mm of "sink" all the metal will contact and give more grip (that's the theory anyway!). The attached pic shows the 10mm plate in the middle of the 12mm rubber, in reality the metal is 1mm higher giving 2mm of rubber overhang at the bottom.



Ben

[Ben Holko]

Both tracks are now finished, yay!

[Doug Conn]

Gorgeous ! Great work.

 

From: rctank...@googlegroups.com [mailto:rctank...@googlegroups.com] On Behalf Of Ben Holko
Sent: Sunday, November 01, 2009 8:58 PM
To: rctank...@googlegroups.com
Subject: [TANKS] Re: M113 design progress

 

Both tracks are now finished, yay!

[Pete Curran]

Ben,

Those tracks will sound awesome when you start driving around

 

Pete

[jvragu47]

So, how much does each track weigh? Looks quite realistic.

[Ben Holko]

55 links, doubled up is 77cm long for 154cm of total track length, weighs
3KG

Each rubber block is 20mm wide, with steel components but excluding bolt
head and nut they are 57mm wide

Ben

[Ben Holko]

Here's a video showing some static track testing;

http://www.youtube.com/watch?v=VHyIxQhfNuc

[Derek Engelhaupt]

Ben,

How much flex do the center guides have side to side?

Derek
T065

[Ben Holko]

depends how hard you try....I guess if you push hard enough 1-2mm

________________________________

From: rctank...@googlegroups.com on behalf of Derek Engelhaupt
Sent: Wed 4/11/2009 9:02 AM
To: rctank...@googlegroups.com
Subject: [TANKS] Re: M113 design progress

[Mike Måne]

Fantastic work! Very realistic! I was anticipating a *Thump* "OUCH!!"
when you were pedaling the track, but it appears to work rather well.
What will you do if the rubber links become worn?

-Mike M.

--
-Mike Måne @
http://moonrcprojects.googlepages.com

[Ben Holko]

I don't plan on doing endless pirouettes or miles and miles on concrete, so they should take a long time to wear out on grass and dirt. As they do wear 1-2mm the steel will begin to contact and slow down the wear process significantly.

Ben


________________________________

http://moonrcprojects.googlepages.com <http://moonrcprojects.googlepages.com/>

[Clark Ward Jr]

How does the chamfering of the outside (noncontact) edge on the gear
teeth help feeding? This is definately outside my area of knowledge
and you've done stunning work!

I also enjoyed the music you put in the video ;)

--
Clark in Georgia

[Ben Holko]

It is the inside edge that is chamfered, that is the edge that touches the
metal components. Without that a tiny deflection and the track could throw
off the sprocket or bind up.

The outside edge is not modified and remains square.