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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Made a special press for broaching
As part of a custom machine I have been fabricating (later) I needed to
broach 1/4" keyways in 1 1/8" holes in two steel flywheels and two collars. I figured no problem, just call up a buddy where I used to work and see if they can press them in the shop. To my surprise they no longer have an arbor press with a high enough throat to press the 12" long broach. Several friends have home hydraulic presses, but they have short strokes and you need to do a lot of resetting to get a broach through, at least two presses and maybe three for each pass of the broach, two passes per hole. That's a lot of fussing around. Hmm. So, I sez, let's build a press just for broaching. I have two possible hydraulic sources. The first is one of those cheap, 4 ton manual Porta-Power sets. But they are very high pressure (10,000 psi) and use small diameter cylinders. I didn't think I could find a sub 1" cylinder with a 12" stroke. Even then it would be a lot of pumping. My other source is an old 12 volt hydraulic system that operated a Corvair convertable top. I built it into a tire bead breaking machine about 35 years ago and it works fine for that, but I no longer use it. I put a gauge on it and it just hit 300 psi as it stalled out. A quick email to DuMont and they said I needed 700 pounds of force for a 1/4" broach in 5/8" mild steel. A 2" piston would give me around 950 pounds. I looked on the HGR Surplus web site and they have lots of pistons. I drove over and immediately found a 2" diameter, 12" stroke cylinder, brand new for $19.99. Cylinders are real cheap at HGR, most are $10 or $20. Since I already had a C frame for the tire machine, I just cut it down to the correct height and bored a few holes and mounted the cylinder on top. The hydraulic pump mounts on the upright and the existing steel braided lines were just right. I'm good to go, only a few hours of work. I cycled her back and forth for a while to bleed the air then give it a shot. It does flex too much, I'll have to add a strongback to the 4" channel frame. And I actually had to start the car I had it hooked to, the extra couple of volts gave me just enough to push through, but it is at the absolute limit with a 1/4" broach. Every keyway broached perfectly, and those shaft collars were tough steel. Here is a photo: http://home.wideopenwest.com/~dthomp.../broaching.jpg Dennis |
#2
Posted to rec.crafts.metalworking
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Made a special press for broaching
"DT" wrote in message ... As part of a custom machine I have been fabricating (later) I needed to broach 1/4" keyways in 1 1/8" holes in two steel flywheels and two collars. I figured no problem, just call up a buddy where I used to work and see if they can press them in the shop. To my surprise they no longer have an arbor press with a high enough throat to press the 12" long broach. Several friends have home hydraulic presses, but they have short strokes and you need to do a lot of resetting to get a broach through, at least two presses and maybe three for each pass of the broach, two passes per hole. That's a lot of fussing around. Hmm. So, I sez, let's build a press just for broaching. I have two possible hydraulic sources. The first is one of those cheap, 4 ton manual Porta-Power sets. But they are very high pressure (10,000 psi) and use small diameter cylinders. I didn't think I could find a sub 1" cylinder with a 12" stroke. Even then it would be a lot of pumping. My other source is an old 12 volt hydraulic system that operated a Corvair convertable top. I built it into a tire bead breaking machine about 35 years ago and it works fine for that, but I no longer use it. I put a gauge on it and it just hit 300 psi as it stalled out. A quick email to DuMont and they said I needed 700 pounds of force for a 1/4" broach in 5/8" mild steel. A 2" piston would give me around 950 pounds. I looked on the HGR Surplus web site and they have lots of pistons. I drove over and immediately found a 2" diameter, 12" stroke cylinder, brand new for $19.99. Cylinders are real cheap at HGR, most are $10 or $20. Since I already had a C frame for the tire machine, I just cut it down to the correct height and bored a few holes and mounted the cylinder on top. The hydraulic pump mounts on the upright and the existing steel braided lines were just right. I'm good to go, only a few hours of work. I cycled her back and forth for a while to bleed the air then give it a shot. It does flex too much, I'll have to add a strongback to the 4" channel frame. And I actually had to start the car I had it hooked to, the extra couple of volts gave me just enough to push through, but it is at the absolute limit with a 1/4" broach. Every keyway broached perfectly, and those shaft collars were tough steel. Here is a photo: http://home.wideopenwest.com/~dthomp.../broaching.jpg Dennis 'Nice piece of work, Dennis. This is a little late to comment about it, but if you're going to use a multi-tooth broach in an open hole, a pull broach might be a lot easier for home construction. The hole provides the only guidance you need. -- Ed Huntress |
#3
Posted to rec.crafts.metalworking
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Made a special press for broaching
On Sat, 10 Jul 2010 20:51:23 -0400, DT
wrote: As part of a custom machine I have been fabricating (later) I needed to broach 1/4" keyways in 1 1/8" holes in two steel flywheels and two collars. I figured no problem, just call up a buddy where I used to work and see if they can press them in the shop. To my surprise they no longer have an arbor press with a high enough throat to press the 12" long broach. Several friends have home hydraulic presses, but they have short strokes and you need to do a lot of resetting to get a broach through, at least two presses and maybe three for each pass of the broach, two passes per hole. That's a lot of fussing around. Hmm. So, I sez, let's build a press just for broaching. I have two possible hydraulic sources. The first is one of those cheap, 4 ton manual Porta-Power sets. But they are very high pressure (10,000 psi) and use small diameter cylinders. I didn't think I could find a sub 1" cylinder with a 12" stroke. Even then it would be a lot of pumping. My other source is an old 12 volt hydraulic system that operated a Corvair convertable top. I built it into a tire bead breaking machine about 35 years ago and it works fine for that, but I no longer use it. I put a gauge on it and it just hit 300 psi as it stalled out. A quick email to DuMont and they said I needed 700 pounds of force for a 1/4" broach in 5/8" mild steel. A 2" piston would give me around 950 pounds. I looked on the HGR Surplus web site and they have lots of pistons. I drove over and immediately found a 2" diameter, 12" stroke cylinder, brand new for $19.99. Cylinders are real cheap at HGR, most are $10 or $20. Since I already had a C frame for the tire machine, I just cut it down to the correct height and bored a few holes and mounted the cylinder on top. The hydraulic pump mounts on the upright and the existing steel braided lines were just right. I'm good to go, only a few hours of work. I cycled her back and forth for a while to bleed the air then give it a shot. It does flex too much, I'll have to add a strongback to the 4" channel frame. And I actually had to start the car I had it hooked to, the extra couple of volts gave me just enough to push through, but it is at the absolute limit with a 1/4" broach. Every keyway broached perfectly, and those shaft collars were tough steel. Here is a photo: http://home.wideopenwest.com/~dthomp.../broaching.jpg Dennis Very nicely done! Either add another lenght of challen at 90' to the back of the press..or simply add a pair of 3/16' x 1' bars down each side of the press. This will prevent bending of both the back and the top and bottom of the press. The secret would be installing them at a distance you can get other work pieces into the press without the bars interfering..such as a large gear. Personally..I think Id make a totally new assembly using a better configuration, but..shrug. Very well done Sir!! Gunner One could not be a successful Leftwinger without realizing that, in contrast to the popular conception supported by newspapers and mothers of Leftwingers, a goodly number of Leftwingers are not only narrow-minded and dull, but also just stupid. Gunner Asch |
#4
Posted to rec.crafts.metalworking
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Made a special press for broaching
Nice. I love doin' stuff like that. Very satisfying.
I went to HGR Surplus: http://www.hgrindustrialsurplus.com/ _12 acres_ of surplus stuff!! Jeez, I could spend a week there. Bob |
#5
Posted to rec.crafts.metalworking
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Made a special press for broaching
On Jul 10, 8:51*pm, DT wrote:
I looked on the HGR Surplus web site and they have lots of pistons. I drove over and immediately found a 2" diameter, 12" stroke cylinder, brand new for $19.99. Cylinders are real cheap at HGR, most are $10 or $20. Here is a photo: * http://home.wideopenwest.com/~dthomp.../broaching.jpg Dennis Nice. I want to get a couple of hydraulic cylinders so went to the HGR website. Lots of cylinders, but most are one of a kind and have no specs listed. So that was disappointing. Oh well................ Dan |
#6
Posted to rec.crafts.metalworking
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Made a special press for broaching
awesome project.
i On 2010-07-11, DT wrote: As part of a custom machine I have been fabricating (later) I needed to broach 1/4" keyways in 1 1/8" holes in two steel flywheels and two collars. I figured no problem, just call up a buddy where I used to work and see if they can press them in the shop. To my surprise they no longer have an arbor press with a high enough throat to press the 12" long broach. Several friends have home hydraulic presses, but they have short strokes and you need to do a lot of resetting to get a broach through, at least two presses and maybe three for each pass of the broach, two passes per hole. That's a lot of fussing around. Hmm. So, I sez, let's build a press just for broaching. I have two possible hydraulic sources. The first is one of those cheap, 4 ton manual Porta-Power sets. But they are very high pressure (10,000 psi) and use small diameter cylinders. I didn't think I could find a sub 1" cylinder with a 12" stroke. Even then it would be a lot of pumping. My other source is an old 12 volt hydraulic system that operated a Corvair convertable top. I built it into a tire bead breaking machine about 35 years ago and it works fine for that, but I no longer use it. I put a gauge on it and it just hit 300 psi as it stalled out. A quick email to DuMont and they said I needed 700 pounds of force for a 1/4" broach in 5/8" mild steel. A 2" piston would give me around 950 pounds. I looked on the HGR Surplus web site and they have lots of pistons. I drove over and immediately found a 2" diameter, 12" stroke cylinder, brand new for $19.99. Cylinders are real cheap at HGR, most are $10 or $20. Since I already had a C frame for the tire machine, I just cut it down to the correct height and bored a few holes and mounted the cylinder on top. The hydraulic pump mounts on the upright and the existing steel braided lines were just right. I'm good to go, only a few hours of work. I cycled her back and forth for a while to bleed the air then give it a shot. It does flex too much, I'll have to add a strongback to the 4" channel frame. And I actually had to start the car I had it hooked to, the extra couple of volts gave me just enough to push through, but it is at the absolute limit with a 1/4" broach. Every keyway broached perfectly, and those shaft collars were tough steel. Here is a photo: http://home.wideopenwest.com/~dthomp.../broaching.jpg Dennis |
#7
Posted to rec.crafts.metalworking
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Made a special press for broaching
DT wrote:
Here is a photo: http://home.wideopenwest.com/~dthomp.../broaching.jpg When you pushed the broach though, did you let up once or twice to allow the broach to recenter itself? Reason I asked is I used a hydraulic press once and tried to just take one long stroke. There was angular misalignment and the broach snapped. Nice solution to your problem at hand! Wes |
#8
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Made a special press for broaching
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