3D printed crankcase splitting tool

[gregsl]

I was/am in need of a way of splitting the case on my Husqvarna 345fx brushcutter rebuild.....

I've designed parts to be 3d printed before so I decided id design a case splitter for this model. I am hoping it is going to be strong enough for the job, but then again I'll likely only need to use it once.

The part is at the printers now and I should have it soon. It's a 3/8 bolt that is 3 inches long. The whole part is about 2 inches tall..

Going to design and print some other tools including a T handle for my darn 4mm Allen key!

 

[fin460]

neat technology

 

[Chris-PA]

What material is it made from?

 

[gregsl]

What material is it made from?

It's going to be made out of PLA (poly lactic acid) which is stronger than ABS plastic. I will post more pics after I pick up the part.

 

[LegDeLimber]

My first thought on this was, well what if you were to put a steel insert that spanned most of the length of the tool....
Then thought, well you'll have almost just built a steel one.
Then thought of washers for spreading the load.....
then I thought " awww dangit leg, stop thinking so much ",
just hang on a moment and watch to see how the off the shelf Nut & Bolt combo holds up.

Yeah the printers are getting interesting. I keep thinking reproduction parts
and some modding trick stuff too.

 

[Chris-PA]

It's going to be made out of PLA (poly lactic acid) which is stronger than ABS plastic. I will post more pics after I pick up the part.

OK, good luck - that isn't what I would chose for such a tool. As an engineer who designed products, and who has used what used to be referred to as rapid prototyping methods rather than "3D printing", this is the thing that makes me shrug: materials matter. One must pick a material that has suitable properties for the intended purpose.

If you have access to a casting facility, perhaps you could use it to make a one-off mold. Of course, you may need to increase the size to compensate for the shrinkage of the material as it cooled so that the final part ends up the right size.

 

[gregsl]

My first thought on this was, well what if you were to put a steel insert that spanned most of the length of the tool....
Then thought, well you'll have almost just built a steel one.
Then thought of washers for spreading the load.....
then I thought " awww dangit leg, stop thinking so much ",
just hang on a moment and watch to see how the off the shelf Nut & Bolt combo holds up.

Yeah the printers are getting interesting. I keep thinking reproduction parts
and some modding trick stuff too.

I thought of the steel insert... I didn't want to spend too much time on this. I'm probably only going to need it once and it is only costing me a couple bucks to print...

 

[gregsl]

OK, good luck - that isn't what I would chose for such a tool. As an engineer who designed products, and who has used what used to be referred to as rapid prototyping methods rather than "3D printing", this is the thing that makes me shrug: materials matter. One must pick a material that has suitable properties for the intended purpose.

If you have access to a casting facility, perhaps you could use it to make a one-off mold. Of course, you may need to increase the size to compensate for the shrinkage of the material as it cooled so that the final part ends up the right size.

I hear ya, I wouldn't have chosen PLA as a material either but it's the only material the university uses in their printers.

Ideally I would like to machine it out of aluminum but that would be overkill.

As for the suitable properties for the intended purpose, I agree with you. But I'm limited to what's available to me.

G

 

[Chris-PA]

That's what most Americans said when somebody started importing Chinese chainsaws.

Funny, but I don't recall "most Americans" posting in that thread. However one particular idiot couldn't seem to stay away, and he turned out to be wrong in just about everything he wrote. It doesn't surprise me in the least that you think you speak for "most Americans" though.

 

[gregsl]

So I picked it up from the print lab today. It feels pretty solid and there was minimal shrinkage. The surface finish is a bit rough but I could care less as long as it works.

There are two sanding mandrels in the background. Intended to be wrapped in scotchbrite a la mastermind method of cylinder dressing.

 

[Jeff Lary]

Cool tool I guess

 

[JB Weld]

Looks great! Let us know how it works.

 

[gregsl]

Worked like a charm! It didn't even flex at all. I was really surprised by how strong this was.

Definetly going to design and print a stihl crankcase splitter next.

I will probably make two of them so I can test the limits of one of them.

 

[Philbert]

Make three and mail me one!

Philbert

 

[gregsl]

Make three and mail me one!

Philbert

I'll see how they turn out. I'll design it tomorrow morning and post it on here for some feedback. Then I'll send some to get printed.

 

[Chris-PA]

Well, despite my scepticism on the appropriateness of the material, you designed and made a useful tool - good job!

What CAD package did you use?

 

[watsonr]

And how much $$$ was it to print that tool?

 

[gregsl]

Well, despite my scepticism on the appropriateness of the material, you designed and made a useful tool - good job!

What CAD package did you use?

Thanks! Your post got me thinking about materials and intended uses... and textbooky stuff! I'll PM you some of my thoughts around this.

I used FreeCad version 14. As the name implies, its completely free! I suppose I could get AutoCad somehow but FreeCad does the trick for me.

G

 

[gregsl]

And how much $$$ was it to print that tool?

Less than $5.... would be about $8 for a nicer surface finish. oh, and $0.59 cents for a 3/8" bolt and $.09 cents for a nut, lol

 

[JB Weld]