Cutting Rubber Tires Cleanly

[Chris1992]

Hi everyone, so I'm currently building a scale replica of my real world car, and have managed to find some scale wheels and tires that match the look perfectly, but the only problem is they are far too wide! This isn't a problem for the wheels themselves as I can cut them with a craft knife easily, however I am unsure how to tackle the tires. I really don't want to make a mess of it, so I just thought I'd ask first in case anyone has any tips. 

Thanks guys,

Chris

[Ace-Garageguy]

I've narrowed quite a few, and this is what I've come up with that works best for me:

1) MEASURE CAREFULLY

2) MARK the first and second cuts with a little white ink from a gel-pen

3) MOUNT the tire to a wheel or a wheel back that has enough of a projection so you can chuck it up in a cordless drill

4) Rotate the assembly slowly in the drill, making sure it's not wobbling

5) While rotating slowly, continue the marks you made earlier with the gel-pen all around the tire

6) With a VERY SHARP, NEW X-Acto or similar, cut on the lines using gentle pressure, while rotating.

7) Cut ALMOST all the way through.

8) Demount the tire and finish the cuts freehand.

9) You can true the edges, if necessary, by sanding on a piece of WET sandpaper (180-600 grit, depending on the material the tire is made of) stuck to a very flat surface.

 

 

[Casey]

I recall reading about a tire cutting method using a horizontal single edge razor blade, mounted to a block, which was somehow height adjustable. No results when I searched here on the forum, so it may have been elsewhere on the web. Maybe the mention will trip someone's memory, as I seem to recall it was a great idea and gave good results. I want to say it was posted by someone who built heavy trucks, but don't hold me to that. 

Here's a kinda-sorta similar post?:

 

 

[Fat Brian]

3 hours ago, Casey said:

I recall reading about a tire cutting method using a horizontal single edge razor blade, mounted to a block, which was somehow height adjustable. No results when I searched here on the forum, so it may have been elsewhere on the web. Maybe the mention will trip someone's memory, as I seem to recall it was a great idea and gave good results. I want to say it was posted by someone who built heavy trucks, but don't hold me to that. 

Here's a kinda-sorta similar post?:

 

 

I remember the same method but likewise don't remember where I saw it. Basically, a razor blade was held horizontally between two adjustable shims and clamped to a table leaving just the corner of the blade exposed. The tire was laid flat against the table and rotated carefully across the exposed blade making a straight and repeatable clean cut.

[BigTallDad]

As a follow-up on Ace-Garageguy's approach, here's a drill cradle I made; it allows hands-free operation of a variable speed drill.

I find the Dremel sanding drum to be an almost-perfect size for mounting the tire. Also, consider taping two fresh #11 Xacto blades together (use a scrap styrene strip to widen the gap, if necessary); that approach will give you a consistent amount of material being removed on all of the tires. Lastly, make the cuts near the edge of the tread pattern, not in the center; mount the edge that was cut on the inside of the chassis area.

For sanding, toss the tire in the freezer for an hour or so. Remove the tire and, working quickly, sand it with 600 grit sandpaper.

Edited February 6, 2018 by BigTallDad

[Ace-Garageguy]

5 hours ago, BigTallDad said:

As a follow-up on Ace-Garageguy's approach, here's a drill cradle I made; it allows hands-free operation of a variable speed drill...

I find the Dremel sanding drum to be an almost-perfect size for mounting the tire. Also, consider taping two fresh #11 Xacto blades together (if necessary, use a scrap styrene strip to widen the gap, if necessary); that approach will give you a consistent amount of material being removed on all of the tires. Lastly, make the cuts near the edge of the tread pattern, not in the center; mount the edge that was cut on the inside of the chassis area.

For sanding, toss the tire in the freezer for an hour or so. Remove the tire and, working quickly, sand it with 600 grit sandpaper.

NICE drill cradle. I need to make one of those.

Good tips too.  

NOTE: Also consider making the slices in the tread grooves if possible. Easier to hide the joint.

[Muncie]

another method - this has worked for me - makes good parallel, smooth cuts

tools: flat surface, wide blade fine tooth hobby saw blade, spacer to fit and align the saw parallel to flat surface, double stick tape

1. determine spacer thickness and identify an available material

2. Layout some strips of tape on the flat surface to attach the spacer

3. place saw blade on the spacer and tire on flat surface - it may be easier to cut the tire by drawing the saw toward you instead of pushing it.

4. cut one groove part way thru, turn the tire over to make the second cut.  After two grooves are cut, finish separating the parts of the tire.

5.  on hollow tires, the center tread section can be trimmed and glued inside the tire to reinforce the glued joint in the tread.  

hope this helps - 

 

[peteski]

 Hmmm . . . I don't see any of Ray's photos. Instead, I see the Photobucket nag to upgrade the account.

[BigTallDad]

11 hours ago, peteski said:

 Hmmm . . . I don't see any of Ray's photos. Instead, I see the Photobucket nag to upgrade the account.

I could see them yesterday, and apparently Ace-Garageguy was able to view them.

Today I'm seeing the same  Photobucket nag to upgrade the account that you are. I took a closer look, and PB has changed the extension to some bogus version of JPG. After re-naming the file, I can see it, but it's only thumbnail size...enlarging that image results in a very fuzzy photo.

Nice going, Photobucket!

Edited February 7, 2018 by BigTallDad

[ChrisBcritter]

They look fine to me - if you can't see them, here you go (I took screenshots and directly uploaded them here):

 

[BigTallDad]

16 hours ago, ChrisBcritter said:

They look fine to me - if you can't see them, here you go (I took screenshots and directly uploaded them here):

 

Thank you sir; I was getting ready to do the same screen-shot approach myself, but you saved me the effort.

BTW, the photos are again showing in my original post...go figure!

Edited February 8, 2018 by BigTallDad

[Chris1992]

Thanks for all the help everyone!! 

[peteski]

I still see the Photobucket nag in Rays post, but I see the screen shots just fine - thanks Chris!

Ray, that is a clever idea and well executed (marine-grade plywood?).  I assume that the little crank is to adjust the drill speed?  Nice!