Portable hydraulic shrinker stretcher

[Classic Bodywork]

Hi, this is a new tool I've made recently, I wanted a portable version of the shrinker stretcher and thought hydraulics might be the solution over leverage. Initial tests are positive but trials over time will reveal any weaknesses. Thanks Ben
PORTABLE Homemade Hydraulic Shrinker Stretcher, Car Restoration Tool, classic car

[IntheGroove]

Replace the hand pump with an electric unit like the type used for pump trailers and you'll get the work done quicker...

[Classic Bodywork]

Yes, I have got an electric hydraulic unit and could connect it up. It will definitely speed it up which could increase its usefulness. 👍

[Frank S]

Since it is obvious you are well versed in the dynamics of mechanical advantages, strengths and stresses of materials. I will take as guess that you are equally as well versed in flow speeds. An electric hydraulic pump was mentioned like ones used for dump trailers these would have too high a flow rate to be practical for this application. their max pressure would not be sufficient either. the port-a-power hand pumps have a max output PSI rating of 10,000 PSI or 689.47bar. while most electric units have only 2,500 PSI. 172.37bar. However, there are electric and pneumatic pump units designed for this application Enerpac is one such name brand. I prefer the pneumatic pumps for field work since I always have an air compressor plus they are less expensive. I like the electric units for bench work,

[Classic Bodywork]

Excellent comment Frank S, the electric hydraulic unit I've got is from an old sausage machine, I can't remember what psi the pump produces, the flow rate is probably not controllable enough despite a variable valve.
The point of this machine is not to replace the purely mechanical hand shrinker stretcher. You won't beat the speed/ controllability of that tool. The advantage of the hydraulic version I've built is versatility and portability, speed wasn't a design factor because it's potential use is relatively small for a car body restorer. It will probably only get used a handful of times during a complete body restoration. There could of course be other applications I hadn't thought of yet to which a powered version might be a benefit.
The Pullmax with shrinker stretcher would be the quickest way to shrink or stretch sheet metal but that is of course the least portable option.

[DIYer]

Thanks Classic Bodywork! We've added your Portable Shrinker Stretcher to our Autobody category,
as well as to your builder page: Classic Bodywork's Homemade Tools. Your receipt:

Portable Shrinker Stretcher by Classic Bodywork

tags: autobody, metalworking

[Jon]

Congratulations Classic Bodywork - your Portable Shrinker Stretcher is the Homemade Tool of the Week!

This is a well thought-out shrinker stretcher, and it's good to see that homemade hacksaw attachment in action building it.

Some more good builds from this week:

Kiridashi Knife by Mazay
Modular Fixture System by Mook
Bandsaw Outrigger Table by Improvised DIY
Engine Crane by th62
Drill Guide by dgbreggin
Vise by Kwandotechnic

Classic Bodywork - we've added your tool entry to our All Homemade Tool of the Week winners post. And, you'll now notice the wrench-on-pedestal award in the awards showcase in your postbit, visible beneath your username:



And, you'll be receiving a $100 cash prize, in your choice of Amazon (US-only), PayPal, or bitcoin. Please PM me your current email address and prize choice and I'll get it sent over right away.

Nice work!

[Classic Bodywork]

Wow, thanks so much, that's really great, didn't expect that at all. What a great community and website this is.
PayPal would be great and my email is btdixey@hotmail.com
Thanks again Ben

[torana]

Hi, this is a new tool I've made recently, I wanted a portable version of the shrinker stretcher and thought hydraulics might be the solution over leverage. Initial tests are positive but trials over time will reveal any weaknesses. Thanks Ben
PORTABLE Homemade Hydraulic Shrinker Stretcher, Car Restoration Tool, classic car

Some time ago, I made a remote pop rivet tool by cutting the head off an air pop rivet tool and connecting the rivet pulling head to the air cylinder with a hydraulic hose, after bleeding out it works well. you might try that approach using the air hydraulic cylinder to drive the stretcher or shrinker. this will allow rapid application of the jaws in succession. Give it a try, I might do the same although I do not have a need for a shrinker or stretcher. i might find one, though!

[Classic Bodywork]

Hi, nice idea yes it would allow fast application I'll have to research how the air pop riveter works as I don't know. Do you know what force it can apply ?