Optimizing Danmar M6 2 Post Lift

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sweet victory
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Optimizing Danmar M6 2 Post Lift

Post by sweet victory » Tue Feb 05, 2019 6:31 pm

I've been thoroughly enjoying having a 2 post lift in my home garage these past few months. It's seriously been awesome. If you've been on the fence about the quick jack or this, the Danmar M6 is what you want. (Not the maxjax)

Out of the box it's a good set up, but there is definitely room for improvement. I would say these the biggest area for improvement is the hydraulic system and the lifting pads.

My first project will address the lifting pads. For a truck, SUV, or most other vehicles, I'm sure this lifting pad works just fine. That's not really the case with the 996, as I've needed to add hockey pucks to make the lift arms clear the bottom of the body. I hate adding spacers between the car and the lift pads since you risk having those spacers slide out. As OCD as I am, it turns into a bit of a circus. After getting the hydraulic lines hooked up, the process goes something like this:
  • Position arms under car
  • Crawl around and place hockey pucks
  • Lift arms a few inches
  • Crawl around each corner for placement check
  • Lower arms
  • Crawl around each other to adjust
  • lift arms a few inches
  • Crawl around each corner for placement check
  • Lift car to desired height
I want to eliminate most of this. I would like to use the existing holes in the Porsche lifting points as a locator for a new lifting pad. This pad could slide upwards and downwards in the lift arm, that way the arm could be swung under the vehicle, and the lifting pad could slide up and locate into the lifting point to ensure a perfect, first time placement. I want it to be tall enough that it will be close to the bottom of the vehicle for ease of locating the pad to the lift point, but short enough that it will still clear the bottom of the side skirts on a lowered Porsche. I played around with the idea of making one height adjustable via threaded rod, but decided against it. So, a few minutes on Solidworks and McMaster and this is what I ended up with. The end that slides into the lift arm is ~ 2.1" long, and should be long enough so that I can slide the lifting pad upwards to ensure its lined up with the hole.

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After I got the initial design figured out, I made a second model that was optimized for 3D printing. I hallowed out the part and shortened the base to save materials and printer time.

Image


Here is what the first print looks like. It's difficult to tell, but I've decided to use a sealing washer as a consumable buffer between the lifting pad and the Porsche lift point. This is a nylon reinforced piece of rubber vulcanized to a steel washer. If you think this is too weak, let me put things in perspective. This washer is design for a 1" fastener. 30ftlbs of torque on a 1.00" fastener is going to produce a ~2200lb axial load. I'm not too worried about the washer, and it can be easily replaced for very little.

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Here is what the original lift pad looks like:

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Here is what the prototype lift pad look like:

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And here, you can see we will need a revision X2 for this part. :oops:

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I've shortened the part by roughly 5/8". I think that should do the trick.

Image
2001 996 C2 Aero

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Einsteiger
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Re: Optimizing Danmar M6 2 Post Lift

Post by Einsteiger » Tue Feb 05, 2019 7:48 pm

Nice. Hope they work out well.

Speaking of pucks, I bought a set of these from a guy on Rennlist who makes them. Very high quality. Smaller than a regular hockey puck, and machined to fit into the 996 jack ports. They should stay put a little better than the NHL version. :P
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Re: Optimizing Danmar M6 2 Post Lift

Post by sweet victory » Tue Feb 05, 2019 8:36 pm

I saw those on rennlist a while back. They look great for floor jacks, but not quiet what I wanted for my lift. A mechanical retainer built into the lift is what I was after. Those pucks will only retain themselves while you raise the jack. Should there be an earth quake or something, I don't want to be pulverized. :cry:
2001 996 C2 Aero

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Re: Optimizing Danmar M6 2 Post Lift

Post by Einsteiger » Wed Feb 06, 2019 7:21 am

being able to 'peg' them into the lift would be a huge plus. It's surprizing that the mfr has not come up with something for Porsche....they should know by now we'll buy anything for the 996 :)
Last edited by Einsteiger on Wed Feb 06, 2019 7:27 am, edited 1 time in total.
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Re: Optimizing Danmar M6 2 Post Lift

Post by gnat » Wed Feb 06, 2019 7:24 am

You aren't lifting the car with bits you printed on a home 3D printer are you? Hopefully that's just a prototype to use as a model for a machine shop?

I know it's possible to tweak the prints to have some tough stuff and done in something like PETG it might be reliable and strong enough, but it's nothing I trust the safety of the car to (much less myself underneath it).

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Re: Optimizing Danmar M6 2 Post Lift

Post by sweet victory » Wed Feb 06, 2019 7:33 am

No, the prints are just to verify the fit. I'll be turning these out of 6061 on a cnc lathe at work.
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Re: Optimizing Danmar M6 2 Post Lift

Post by Einsteiger » Wed Feb 06, 2019 7:46 am

...and then start working on your patent application. ;)
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Re: Optimizing Danmar M6 2 Post Lift

Post by sweet victory » Wed Feb 06, 2019 7:53 am

Not sure if you can patent a peg. :lol:
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Re: Optimizing Danmar M6 2 Post Lift

Post by gnat » Wed Feb 06, 2019 7:54 am

sweet victory wrote:
Wed Feb 06, 2019 7:33 am
No, the prints are just to verify the fit. I'll be turning these out of 6061 on a cnc lathe at work.
It's awesome how much time and money 3D printing saves for prototyping situations like this.

Due to my lack of patience there are many projects I've never bothered with due to the time and effort involved getting things just right. I'm finding I'm starting to tackle more and more with my 3D printer where I can do the hard work in software and then wait a few hours to see it and test it out. Then I can tweak a few settings for me production prints to have the desired strength and look.

One of these days I'll get into CNC work too when I have the space to build a good sized machine.

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Re: Optimizing Danmar M6 2 Post Lift

Post by gnat » Wed Feb 06, 2019 8:01 am

sweet victory wrote:
Wed Feb 06, 2019 7:53 am
Not sure if you can patent a peg. :lol:
You can patent anything that isn't already patented or has prior art.

You might lose on a challenge, but it's not really costly to file the patent.

If you start selling it and it becomes popular, however, expect some shop in China to not give a shit about our patent law and undercut you with a cheap knock off that may or may not kill someone when their welded aluminum pipe collapses...

I vote that you put the design info up somewhere like Thingverse and (if you are interested) produce sets in small quantities for a reasonable price (material, power, time, and beer) for those interested.

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