Tom O
Ultra Member
Haas tips and tricks has a video that drills and retracts then spins in the opposite way to clear the nest before continuing drilling.
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20 ton jewelry press
- Thread starter Janger
- Start date
Tom Kitta
Ultra Member
Well, I try it and see how it works on manual machine - but it is a bit more then 2 sec operation - it takes a bit more to stop the spindle, change speed, change direction, spun it up, watch chips fly away after 2 sec, turn off, stop it, reverse, set new speed. I think it may be just easier to brush the chips away with a brush.
historicalarms
Ultra Member
The one I am referencing has a hyd ram & porta-power type oil pump. the spring is inside the ram.
When I built my devoted 20T brake (non-adjustable) I couldn't source the right springs for the longest time cheaply. Then I found a trampoline company in Calgary (Manchester) that had a great assortment. They worked like a charm.
Presses are great tools. If you use an air over hydraulic jack like I do, remove the trigger lock that comes with many of them. Guys crush their arms off due to those stupid things. Big safety hazard.
Presses are great tools. If you use an air over hydraulic jack like I do, remove the trigger lock that comes with many of them. Guys crush their arms off due to those stupid things. Big safety hazard.
John you have far too much unused floor space in that garage of yours. It's disgraceful
That's looking good.
OK dumbass question time. According to this, 1" threaded rod can hold 4,900 pounds tension. So 4 of them = 19,600 pounds. 20 tons on the jack is 40,000 pounds (so it exceeds rod rating)
https://www.engineeringtoolbox.com/loads-hanging-rods-d_1341.html
This link says 36,350 pounds for 1" so 145,400 pounds for 4 rods, so 72 tons capability
http://www.barnhillbolt.com/page/specs/ATR.pdf
Do the alloys vary that much or what am I missing? What grade are you using?
OK dumbass question time. According to this, 1" threaded rod can hold 4,900 pounds tension. So 4 of them = 19,600 pounds. 20 tons on the jack is 40,000 pounds (so it exceeds rod rating)
https://www.engineeringtoolbox.com/loads-hanging-rods-d_1341.html
This link says 36,350 pounds for 1" so 145,400 pounds for 4 rods, so 72 tons capability
http://www.barnhillbolt.com/page/specs/ATR.pdf
Do the alloys vary that much or what am I missing? What grade are you using?
Brian Ross
Active Member
I'm not sure about the first reference. Regular 1018 steel has a tensile strength of about 60000 psi. So the second reference seems to be right on and it looks like it is plenty strong for the press. Grade 8 threaded rod has a tensile strength of about 150000 psi - much stronger than mild steel.
historicalarms
Ultra Member
the content of this thread at the moment is sort of apropos, last week I bought a couple grade 8 bolts for a specific project in mind . I had a couple of lesser hardness bolts on the bench at the same time, one of these I wanted to cut a "measurement mark into with a file but by mistake I picked up one of the grade 8 bolts and hit it with the file and the file bit in quite readily . Not what I expected, to say the least, so I dug up an old grade 8 bolt from a Caterpillar D8 from mid 60's era...that file slid like glass over the "old bolt" of supposed same grade.
That looks like a useful app Rudy, can you share the link?
The max tensile value of the first link I referenced is very low by comparison, that's what made me wonder. Maybe 'threaded hangar rod' means something different? It looks like a somewhat encompassing engineering site but I notice no reference to specifying Grade/SAE number, hence the question. Sorry for the tangent, figured it would be useful discussion since we are buying this stuff to deal with relatively heavy forces & ideally don't want things to go sideways.
The max tensile value of the first link I referenced is very low by comparison, that's what made me wonder. Maybe 'threaded hangar rod' means something different? It looks like a somewhat encompassing engineering site but I notice no reference to specifying Grade/SAE number, hence the question. Sorry for the tangent, figured it would be useful discussion since we are buying this stuff to deal with relatively heavy forces & ideally don't want things to go sideways.
Dabbler
ersatz engineer
Threaded hanger rod is non-graded rod that for purposes of discussion should be considered SAE grade 2 (although it is probably less). When figuring out tensile on any threaded rod, use the numbers for a bolt of the same diameter.
Note that in almost every case, UNF rods are stronger than UNC threads, as it is the minimum cross section that fails, and seldom the threads. UNF threads leave more cross section after threading.
For rule of thumb, I use 120K psi multiplied by the surface area for grade 8 and 80K for grade 5. These de-rated values allow for the thread form, and give reasonable results. For Grade 2, most manufacturers don't give good quality control in grade 2 fasteners, I use 30K instead of 60K. Grade 2 might as well be ungraded.
On a side note. Most metric fasteners are Grade 7 or better. (7 is sort of an orphan designation) I use 100K times the surface area for all metric fasteners, regardless of declared grade. (unless it is chinesuim, then I use 30K again)
It is silly that we are all still using lbs-force instead of Newtons. I trained in Newtons, but just feel more comfortable describing thing in the now-defunct units lbs-force.
Note that in almost every case, UNF rods are stronger than UNC threads, as it is the minimum cross section that fails, and seldom the threads. UNF threads leave more cross section after threading.
For rule of thumb, I use 120K psi multiplied by the surface area for grade 8 and 80K for grade 5. These de-rated values allow for the thread form, and give reasonable results. For Grade 2, most manufacturers don't give good quality control in grade 2 fasteners, I use 30K instead of 60K. Grade 2 might as well be ungraded.
On a side note. Most metric fasteners are Grade 7 or better. (7 is sort of an orphan designation) I use 100K times the surface area for all metric fasteners, regardless of declared grade. (unless it is chinesuim, then I use 30K again)
It is silly that we are all still using lbs-force instead of Newtons. I trained in Newtons, but just feel more comfortable describing thing in the now-defunct units lbs-force.
Chicken lights
Forum Pony Express Driver
Why do you say that?It is silly that we are all still using lbs-force instead of Newtons. I trained in Newtons, but just feel more comfortable describing thing in the now-defunct units lbs-force.
Inch pounds and foot pounds make more sense to me then a Newton metre.
I’ve got a Newton metre torque wrench that’s just a paper weight, more or less.
This is a good discussion. I appreciate the thoughts on safety. I bought the rods and nuts from a reputable supplier ($80 ish) and the rods are rated B7. That is apparently better than Grade 5 but not as good as Grade 8. The rods are stamped on the end B7 and are 1" NC. Definitely not the cheapie stuff from Princess with no rating or grade at all. I would assume material like that is not even grade 2.
I found a chart https://www.almabolt.com/pages/catalog/bolts/proofloadtensile.htm
Comparing relative strengths on the chart - grade five 1"-8 has a proof load of 51500 lbs. I think this means 4 rods * 51500 lbs = 206,000 lbs. The jack can provide 20 tons * 2000 lbs/ton = 40,000 lbs. I believe this means the rods would fail at 100 tons and that is 80 tons more than the jack can provide. I don't know where safety factors come in and I'm not an engineer so I'm just making some assumptions. This is a tested and published plan - my spouses teacher made one of these as well and has been using it for years. I hope this is adequate. I'm going to add a safety curtain too. One point in the plan they put two nuts on the load taking sides of the rod. I assume this is a locking type of arrangement not adding much to the strength.
The same chart says grade 2 is 20,000 lbs per 1" rod. Quite a bit less.
@historicalarms - Do those Grade 8 bolts you think are weak have the right markings on the head? Where did you buy them? What are the markings on the old bolts?
I found a chart https://www.almabolt.com/pages/catalog/bolts/proofloadtensile.htm
Comparing relative strengths on the chart - grade five 1"-8 has a proof load of 51500 lbs. I think this means 4 rods * 51500 lbs = 206,000 lbs. The jack can provide 20 tons * 2000 lbs/ton = 40,000 lbs. I believe this means the rods would fail at 100 tons and that is 80 tons more than the jack can provide. I don't know where safety factors come in and I'm not an engineer so I'm just making some assumptions. This is a tested and published plan - my spouses teacher made one of these as well and has been using it for years. I hope this is adequate. I'm going to add a safety curtain too. One point in the plan they put two nuts on the load taking sides of the rod. I assume this is a locking type of arrangement not adding much to the strength.
The same chart says grade 2 is 20,000 lbs per 1" rod. Quite a bit less.
@historicalarms - Do those Grade 8 bolts you think are weak have the right markings on the head? Where did you buy them? What are the markings on the old bolts?
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That does look handy. It seems to be called iEngineer on the apple iOS app store. It's even Free! EDIT-> Metric screw tables are $2.79
that is exactly what the app is called. I have not paid the $2.79, thus only have access to the SAE side...
John, here is what the app says for a 1”-8 UNC Grade 5 bolt
seems a bit of a variance for sure, no idea why (maybe different testing standards?)
regardless, I think you are safe in any case with 4 of them and a 20ton jack.
historicalarms
Ultra Member
Both the old cat bolt & the new bolt had the same 5 head ridges and both are fine tread. The new bolt came in a twofer package from a local hardware store , packaged with a "SAE fine tread Grade Eight label." I have grade 2 & 5 bolts in my bolt bin and the new bots seem to be a bit harder than the gr 5 but nowhere near as hard as the old gr 8 .