Ooops , bent it !

I was installing some turnbuckle/chain sway control on the 3 point hitch on my "new" tractor , and I was inattentive (I f***ed up) and bent the tension rods on my HF hydraulic jack press while pressing some bolts out of the lower lift arms. I want to replace rather than straighten and I'm thinking 4140 might be a good choice . I've replaced the 12 ton jack it had originally with a 20 ton unit ... The original rods are 3/4" , I don't know what they're made of . I can get enough 4140 in 3/4" for a not-outrageous price to have a couple of feet left over for future projects . I figure the max tension load on each will be around 20,000 pounds which should be well within the limits of 4140 . Threads will be single point cut NF . Unless someone can recommend a better alloy for this ... I only want to do this once !

First off. I don't know what high tension rods you are referring to. I have jack style 12 and 20 ton presses. I don't think they have those. Which leads us into the next part.

The cross pins that support the table on the press can support the full force of the hydraulic. I can tell you first hand you will either tear the upright construction steel or bend the top cross member before those fail. I've done both. The cross pins on both of my 20 ton presses are about 0.780in. Not much more than 3/4. 3/4 should be fine.

The rods I'm talking about go from the top cross member of the frame to the cross member that the top of the jack pushes on . The plate/"ram" the jack sits on slides on those rods . I'm going to order that 4140 , 6 feet for 63 bucks delivered . Shipping costs as much as the material !

Oops wrong. That price was only for 3' Sorry. Looks like McMaster is the better deal afterall.

Looks like my post for McMaster didn't show up. It was 50 bucks and 40 bucks shipping at Mcmaster Carr.

This is for a piece 6 feet long , that 63 bucks was before they added sales tax . which brought the total to 70 bucks . I'll probably order a piece of hex stock to make new nuts , depends on how they look when I get it disassembled .

Actually , I have a piece of 4140 round stock that I can use to make the nuts . I can make them either hex or square and larger outside dimension than the originals . I've already beefed up the top cross bar on the frame , I'll probably replace the cross bar the jack pushes on with some heavier wall stock I have on hand ...

Yep 6' piece is 50 bucks at McMaster. It was MSC that did a bait and switch showing me 3 foot pieces when I clicked on 72" length.

For small quantity I always check those two even though they have a reputation for being high. Sometimes single piece stock is reasonable. Other sources are usually much better when you start getting into even modest quantity. I buy a variety of stuff from both of those vendors. Some stuff from Zoro too, but Zoro is usually only best if I have one of their discount coupons. Almost never on metal stock.

I'm pretty functional, often making square drives that will fit a particular 12 point wrench or socket, but there is certainly an elegant look to a well made hex with a nice chamfer.

------------------------- A hex head fitted fairly closely to a 6 point socket holds up better than alternatives when cut from mild steel. Most of my sawmill has 9/16" hex heads on 3/8" bolts or milled into the ends of the 3/4"-10 track and log leveling screws. I keep a disassembled T handle drive and a gear wrench in my pocket for them, as there are only a few safe flat spots around the work area to leave things and whatever falls is lost in sawdust.

The log leveling adjusters in particular are turned often while heavily loaded to fine tune for log taper. Unlike small commercial bandsaw mills with attached toeboards the log supports are separate from and log weight doesn't deflect the track the saw head rolls on. Mine can be set up level or gravity assisted on uneven sloping ground.

I am aware, but a square drive is faster and easier to machine for often single use tools. A year ago I made a brake caliper tool with two pins and a square drive for my son's Malibu. You have to turn the caliper back in when installing new rotors and pads. He parked it a couple months ago and will be getting rid of it. I won't even remember what that tool is for a few years from now. Okay, I'll probably remember, but it only got used once, and with the ever growing web of self repair denial in the industry (all industries) its unlikely it will ever get used again.

I am aware, but a square drive is faster and easier to machine for often single use tools. A year ago I made a brake caliper tool with two pins and a square drive for my son's Malibu. You have to turn the caliper back in when installing new rotors and pads. He parked it a couple months ago and will be getting rid of it. I won't even remember what that tool is for a few years from now. Okay, I'll probably remember, but it only got used once, and with the ever growing web of self repair denial in the industry (all industries) its unlikely it will ever get used again. Bob La Londe

---------------------------- The quick fix is two or more axial drill holes in one end located by eye for an HF adjustable pin spanner wrench. Cross-drilling for a rod is quick if the center can be blocked. Neither can stand as much torque as flats. The best high torque driver I've found for a square is a large pipe tap wrench which balances the forces. Two bars or square tubes with the ends overlapped and joined by bolts can work well too, as long as the bolt holes don't weaken it much.

The two bars can also be recessed with the two halves of a hex, with opposing points on the parting line. There is just enough clearance above to mill the angled faces with an end mill. Instead of a complex and hard to measure layout I cut a square notch the width and depth for one hex flat and milled the angled faces to meet it in the corners. It was done when the two bars would close tight on the hex. I made it to break loose and reshape distorted 3/8" brake line flare nuts, it works on 7/16" as well.

Usually such tools are small enough for my sample kit so after using them I clean them up neatly enough to show to engineers.

A couple of years ago we used a disk parking brake screw retractor in auto shop night school. The students wanting to learn maintenance all drove older cars.

I'm old school that way. I still have a flat piece of bar stock with a hole drilled and tapped through it for a long bolt in my tool box for compressing brake calipers. I also have home made strut spring compressors mde from two pieces of all-thread with two pieces of pipe slid over each piece. Then a couple lightish tie down hooks welded to the piece of pipe. I laughed when my brother in law tried to tell me (former GM/Delphi guy) you had to have a ten thousand dollar hydraulic machine to work on struts. I think I surprised him a few times.

Still speaking of the BIL. When he went on about how only people with lots and lots of money could do CNC machines I walked him out to my shop and showed him my Taig. He showed real surpise at that one. Another time I had a starter go out on an old Force Outboard and he tried to convince that the chances of one from another motor working were between slim and none. I walked him back out to the shop an hour later and fired up the motor in front of him. Brilliant guy in some ways. An actual educated engineer, but outside of his scope he couldn't see it... Or maybe he just took what some other engineer told him at face value. He left Delphi around the time of the big Government Motors fiasco with GM and went to work running a plant that had CNC machines you couldn't fit in my building making jet engine parts. Maybe Boeing? I forget. Somewhere up in the Pacific Northwest.

I am not particularly neat or fancy about one off tools. I have a lot of them I made and a fair number I bought that I literally only used once. Driver for the head bolts on the 1.7L VW engine they but in the Dodge Omni. Offset open end wrench for the carburetor mounting bolts on a Ford Grenada with the little six cylinder (not the 300, but the same design smaller one). Similar offset wrench for fire sprinkler heads. Various brake tools. A couple different clutch alignment tools.

The brake caliper unscrewer was just a piece of stainless round bar with two holes for press fit pins drilled in one side, and a square milled on the other. It worked, and didn't take long to make. Less time than driving to the store to buy one. I do have a Harbor Freight adjust able spanner. Actually both types, although I am not sure they both came from harbor Freight, but the made for purpose tool worked far better.

I also have home made strut spring compressors mde from two pieces of all-thread with two pieces of pipe slid over each piece. Then a couple lightish tie down hooks welded to the piece of pipe. I laughed when my brother in law tried to tell me (former GM/Delphi guy) you had to have a ten thousand dollar hydraulic machine to work on struts. I think I surprised him a few times.

----- I've had a lot of trouble with a cheap strut spring compressor and maybe should have made my own that fitted better. The whole strut assembly wasn't that much more expensive so I bought them, likewise the whole headlight assemblies instead of trying to keep the lens clear. I've taken to replacing the maximum instead of the minimum while fairly inexpensive parts are still available. Since retirement the car and truck deteriorate more from age (rubber, plastic, rust) than wear.

----- Still speaking of the BIL. When he went on about how only people with lots and lots of money could do CNC machines I walked him out to my shop and showed him my Taig. He showed real surpise at that one. Another time I had a starter go out on an old Force Outboard and he tried to convince that the chances of one from another motor working were between slim and none. I walked him back out to the shop an hour later and fired up the motor in front of him. Brilliant guy in some ways. An actual educated engineer, but outside of his scope he couldn't see it... Or maybe he just took what some other engineer told him at face value. He left Delphi around the time of the big Government Motors fiasco with GM and went to work running a plant that had CNC machines you couldn't fit in my building making jet engine parts. Maybe Boeing? I forget. Somewhere up in the Pacific Northwest.

-------------------------- Engineers vary a lot, some narrow and good with formulas but nothing beyond their education, others with a wide range of skills and interests. I suspect many in management had been poor at design. I tried to learn how to fit with each. The best fit was when they determined what was needed and I how to build it. I had to reestablish my ability with each new one, sometimes by greatly simplifying an overly complex solution by having a wider box to think in. Being able to show them machined metal models helped a lot.