MadModder
The Shop => Our Shop => Topic started by: PekkaNF on September 20, 2015, 08:56:46 AM
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I Have a small cheap 2 metric on bottlejack. Sometimes a small toejack would be nice. Doeas anybody has a simple, but effective toe jack palns or picture to share?
I have seen some some pictures of very crude ones, that put load on hydraulic slinder rod/seal. I don't like that. Then I have seen a picture of the one that must be a functional, but a bit overkill with all machined slides etc. I can relae to that, but this is chinese jack, I'm not going to chrome it.
Thanks,
Pekka
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Pekka
Have a look for oxtools YouTube vids in one early one he does just what you are doing note he does a mod to a potapac one in a recent one so look back a bit
Stuart
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That one?
Pekka
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Yep
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Here is a simple one I made. Someone copied it and found that it was better to have a baseplate with the 'toe' cut out to go under the machine.
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Last week was busy, but made a sketch of traditional hydraulic toe jack. Bought cheap 2t bottle jack and checked it. I could not trust it to support any load near my fingers - clogs, wedges and timber.
Therefore "Plan B": Screw jack type.
First scissor jack I checked seemed to have nice thread but plastic nut...don't get me wrong, I think that plastic can be used an lot of stuff but I would not buy cheap lift and use it, sooooooooo I looked up on table of the metric screws and whilst M10 seems to be a little marginal to lift one end of the 1t machine, M12 seemed to have enough security. Some more doodling and quick visit to local nut n' bolt shop produced 180 mm thread length M12 bolts with 19 mm AF hex. I wanted to have normal hex head - easier to use standard ratchet wrench and avoid using bar, etc.
Hard look on the corner of my dungeon and with a bit digging I found 50 mm C-channel, 40*100 mm L-section, flat bar and round bar. All hot rolled and least somewhat weldable. Hardest part was to decide how to mount the screw to minimize side load - all tables assume that the bolt/nut is mostly in pure tension (no bending). Decided to use classic round dowel nut/pivot design. Now this 180 mm length does not look too long anymore....on my disposable all welded structure there were no problems to reach effective 100 mm lifting height for dolly, but half way I got this idea of making it more professional and easier to repair and I'm watching my daylight disapearing. Also I found that one 25 mm bar that has carbon inclusions and eats my drills....now I have to paint/mark it to be used only where crappier iron will do.
Got to the point where I'm having most parts ready.
pekka
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Just got home - and it is about to hit the hay or tomorow will be even more proverbial....
Here is a consideration: How well stick weld will hold hot rolled parts together: I need to weld the bushing into "toe" to allow a degree of movement for the barrel nut. Longer the weld, stroger it will be, but at the expence of the lifting height.
The part is now near 30 mm long, two beads, both sides? If I could cut it 20 mm long it probably would allow just enough height.
Or I could buy 8.8 grade all thread and weld long nut to it if it really comes to that. But I like standard parts.
Pekka
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Bit more progress. One hour goes fast.
There is some extra material on column. One retainer and some minor features left, but at 100 mm lifting length is a bit marginal.
Pekka
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Following along with interest Pekka :thumbup:
Rob
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That swivel bolt is bit overkill, but haven't been able to locate (locally) DIN 6319 Spherical washers, those would give a bit more headroom and allow enough of flex, play and inaccuracy:
https://www.ganter-griff.de/en/products/3.2-Mounting-positioning-leveling-via-clamping-bolting-and-supporting-parts/DIN-6319-Spherical-washers-Steel
DIN 6319 CD pair to bottom end and DIN 6319 D/G washer and DIN 6330 nut on the top end?
I'm sketching/piling up crap stock metals for dolly, have to build them too and it would be nice if these were compatible. Although not too bad to lift a bit with tiny toe jack, put stabilizing 2*4" onder the machine, lift other end and continue with bigger toe jacks (that I can borrow, but those are big/heavy and 30 km away - not handy for every and each move and maintenance).
Small tools and baby steps, all under 2t.
Pekka
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Pickeled hot rolled parts in vinegar overnight...better, but still some slag left. Looks like in the summer overnight is enough.
Took a picture and then sprayed them with steam washer, almost all came out, but dunk them overnight.
Pekka
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First jack has been waiting welding - my brother normally welds stuff for me. He has better welding machines and training. I have only 160A inverter, 3,25mm sticks are max.
Pekka
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Should work good.
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Yep, but nicer on a big MIG and he was a certified high pressure tube/vessel welder a little while. My welding is not that great and this is a lifting contraption and used very close to expensive machinery and my life and limb.
I rather have somebody who actually can weld to weld it, even if he must use my welder.
Pekka
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I feel the same there has to be a comfort zone. I'm starting out welding as part of this hobbyitis thing One day I'll try cutting and etching to see just what kind of penetration I'm getting. Welding is about the last thing I need to do almost anything its a strange feeling to walk through a store or pawnshop not seeing anything to buy!
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Uhm, Safety sally here.. but would that thread really hold up to sustained weight for a while? I stripped galvanized M16 rod when changing the big block springs on my -66 street car.. that was a bit of a shocker.. (he he he.)
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Good point, but you probably bought cheap screw rod....they are not meant for any real load. I'm using 8.8 hardware from reputable source.
P.S. did you change your pants when spring expressed it's true nature?
Pekka
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No i used proper 8.8 hardened rolled screws actually because otherwise the nuts just binds when compressing the spring.
And yeah when it snapped i kinda needed to make a wipe check and smoke a pipe. :palm:
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I thought that I found perfect DIN parts for MK2-model...only thing is that seems to hard to get from Finland (one tool shop nearby lists them), but should go there personnaly to get them....four shops in Germany sells small amouts to private persons, some have miniminum order value of 300€, some don't deliver outside of germany, some have minimum one box (50 or 100 pcs)...
Dang. Would like to buy 10-20 pcs. each. I would have some other uses them too.
Sechskantmutter DIN6330B | 1,5d hoch M12 SW19
Kegelpfanne einsatzgehärtet | für M12 DIN6319D
Kugelscheibe einsatzgehärtet | für M12 DIN6319C
Kegelpfanne vergütet | für M12 DIN6319G
Pekka
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Like waching paint to dry :D
On Monday I visited brother and he welded parts together. I tested it today and it seemd to work. There were some scratches at the back of the column. Filed some corners down and now it looks like it would work.
Still thinkking how to shape toe. It is pretty long now and will not help stability.
I'm wondering if paint would hold on it. Probably light phosphating would work better.
Pekka
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Let's beat this to death. Dead beat?
Sprayed it with 33% phosphorous accid, let it set for an hour, put it oven to dry and painted with firs spray can I found. It's very blue.
Pekka
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So the phosphoric acid spray was just a simple phosphate passivation?
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So the phosphoric acid spray was just a simple phosphate passivation?
Yesh...I used normal cheap spray can (ex. ant repellent pump can), sprayed, wiped clean (there is some iron-um-sirate-no-what?) and put it oven. Lew mailed on one thread "light phosphating" and it's done in industrial scale with very weak solution and hot. I have found out that even it is very small change, it gives a good key to paint and when left unpainted holds lubricant better than freshly milled surface.
Pekka