Hydraulic Jack as thumbnail die press tests

[jlrussell4]

p.s Has anyone ever looked into being able to allow logged on users to Instant Message one another if they care to? I know you can send a private message etc etc but if logged on back and forth questions and answers or just chat could be good for some

Dee,

If posters went to instant messaging to discuss their metalshaping, we wouldn't be sharing with the rest of the community. There are times I wish we didn't even have P.M.'s. Way too much is discussed off line that could benefit the metalshaping community. I know for a fact that some of the problems we have had on this forum came from feelings stirred up on P.M.'s. On the other hand, there are somethings that are best discussed with P.M.s I guess it's just up to the individuals involved.

P.S. my question was directed to David Coffer who said he didn't like his recip. machine.

[jlrussell4]

D.C.,

I thought you were using this as a shrinker only. Now I understand your disappointment.

[kit]

Originally Posted by Dawai

Jim,

1, it has no "give" if it can't shape, it stalls.
2, it has no "stored energy" (perhaps a flywheel would solve that)
I've been working to solve the issues for about a year now. It's spit parts out at me a few times now. I've downsized the eccentric twice now.

I'd put a small Yoder style head on it personally that would address all those issues, I've used the same thumb nail dies on a helve, a fixed stroke machine and the Yoder style machine, no contest, the Yoder runs them way best.

[Dawai]

Jim,

I've cut the thumb down twice now on the dies trying to get them to work with thicker metal. It makes a nice ripple about 1/8" tall.. pull it back in thick metal and it chokes. I gauge it to close the metal but not stretch it.

I have some test pieces I ran last week I can photo.. on 19-22 it rolls a edge like nobodies business. If a man had room to leave it set up just for that metal. It'd be fine. one of them cases where my ocd is not good. (faster horses.. younger women.. more money)

A "spring stored energy" tool is better in my book. A mini helve, or yoder, or munga man style machine.

I have worked on the non marking brake-pad shrinker jaws too here.. they work.. they get really hot and stress the metal thou.. meaning perhaps they slip too much.. You want "clean" metal on them, not lightly oiled. I got a idea on a overhead helve or yoder they will shrink like crazy.. When that amounts to something we can all use I'll post it.. (after the rotten tomato looking foot goes down)

[jones_d56]

For a "Homemade" machine a slight amount of flex in the frame might not be such a bad thing or even some form of hard rubber behind the back of top and bottom dies?

It would allow less powerful motors and or construction to continue running without any chance stopping / jamming or breaking...if they find it harder going in areas where the metal is slightly thicker, especially if without quick adjustment to alter stroke length /pressure?

Probably it would take a few more strokes to work an area but.. beggars like me can't be choosers...!

D

[Dawai]

Dee, on the reciprocating machine, I thought about leaving the stroke longer and just "spring loading" the bearings where if it could not shape it'd lift the bearing blocks. IT needs a flywheel to carry it through too I think.. mass.. no room for it on this frame..

Mass and inertia.. if you hung a weight on it's bearing plate do much better at "that" aspect.

I sometimes "wonder" if the real deal would not be a "rounded" thumb, and a pivot arm like a helve, It'd bend the tuck metal in a circular motion like a roller.. Kinda like the guy was doing with the hammer working the dent out.. pull the metal as it hits. You'd be fighting that as you withdrew the metal to shrink it thou.

The tucking rollers worked so well by angular pulling, drawing the metal inward. Perhaps I should just be working on a planishing hammer behind it..

I got a ditch to dig this morning to the chicken lot... if my foot is still working I may spend some time in the shop playing.

There is no crazy ideas, but a lot of people who are closed minded.

[jones_d56]

Just asking... has anyone had any luck using a reciprocating sabre saw or much much better still the sds type rotary hammer drill as the driving force for above small homemade frame dies / thumbnail etc?

I picked up both these in a second hand shop for £10 the pair.

Both have variable speed...

The sabre saw has a long stroke 25-30mm (little over 1 inch) and not designed to be so strong , could space it above with adjustable travel through, put piece of hard rubber similar to pic i just found? between head and dies, better though the sds rotary hammer drill...

It has about max 22mm stroke (little under 1 inch or 3 barley corns... or the width of a thumb at the base of ones nail, seems a little vague to me, but i digress) anyway because it uses air between the driving head and the piston it will compress and never stall or jam etc... they are fairly robust used to break lumps of concrete, come in small medium and well large! again a buffer of rubber could be used between head and dies should it be required?

Would be quick if louder than i would like... but, well I wondered if anyone has experience in the real world of similar that i can read about, rather than in my head?

D

[Dawai]

A demolition hammer- ie hammer drill.. that has a switch to "hammer only" I discovered has a piston and is a jack hammer like inside. (Richard K sent me on that quest). it is pretty logical that it would work well. There is a drawing-pdf on the internal workings on the harborfreight website.

The smaller hammer drills have like a star unit inside them.. They will not hammer only.

The sabre saw, sawzall.. the eccentric is nowhere near strong enough inside, the brands I used over the years, milwaukee, Dewalt even have a shear pin inside that breaks first..

I've repaired over the years hundreds of these.

[jones_d56]

Dawai
Yes the sds Rotary Hammer Drill's use the Rotary stop feature, as i mentioned, i felt the piston transferring pressure though the air chamber to the head would act as a cushion to stop stalling / jamming and this also gives a very handy variable depth because of this compression of the air in the piston tube...

If one takes the drill (on rotary stop) and keeps it about 10-15mm away from concrete etc... to long stroke tends to bounce the drill off the concrete but as you move forward the air chamber compresses more taking up slack and the percussion stroke decreases etc...
(thanks for the harbour freight diagram, i hadn't found a cutaway type plan and was guessing its internals somewhat) not far off though

The idea seemed to me like a possible use (after all its not so different from a air planisher on steroids), I rather thought that i would have found lots of people using something similar???

what did you mean by (Richard K sent me on that quest)? did he or your good self have a go in the past? any feedback positive?

D

[jones_d56]

Had another good find....
home wood work lathe with tailstock and drills and face plates chisels and more...£50 s/hand
5 speed
I will shorten the length of the bed anyway (won't be turning spindles!), and perhaps could (in the short term, until i find a good motor and pillow blocks etc) bolt it on top of my frame to power an eccentric using the outboard end, as most designs of reciprocating machines do... then remove it as use it as a Lathe!

or I could still use it as the lathe if i stand on a tall box!

D