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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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bport -- powerfeed question
greets all..
having some trouble using/diagnosing the powerfeed on a Jhead bridgeport. i can get it to engage in both directions... "Up" has alot of power, i can't stop the quill by pulling on it. however, downfeed seems to kick out with little resistance. ie, using it to drill holes.. it'll feed down, but as soon as the bit touches the workpiece, out goes the powerfeed. anythoughts? is this thing broken? or am i not engaging it correctly? any help appreciated. -tony |
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bport -- powerfeed question
On Thu, 09 Oct 2003 20:09:33 GMT, "tony" wrote: ===greets all.. ===having some trouble using/diagnosing the powerfeed ===on a Jhead bridgeport. === ===i can get it to engage in both directions... "Up" has ===alot of power, i can't stop the quill by pulling on it. ===however, downfeed seems to kick out with little ===resistance. === ===ie, using it to drill holes.. it'll feed down, but ===as soon as the bit touches the workpiece, out goes ===the powerfeed. === ===anythoughts? is this thing broken? or am i not ===engaging it correctly? === ===any help appreciated. ===-tony === It sounds like the trip lever is out of adjustment. There is a small setscrew used to adjust the quill trip pressure, located on the bottom of the quill. It does not take much of a turn to make a lot of difference. These are part numbers J-42 (trip lever) and the adjustment screw is #J-279 Some other items that can cause this exact problem is: The pivot pins on the linkage that is on the lever on the left side of the machine (cover has 2 screws and has a bronze or brass linkage rod extending out of it) can come out, and not provide sufficient throw to lock quill in power feed. Another cuplrit is the trip plunger. Its a small dumb bell shaped item with two balls about 5/16" in diam on a shaft of about 1/8 " inches in diameter, made in one piece. Looks like - O-O- If the piece between the ball gets broken it does not sense the pressure properly. The item costs about $5.00. Its item number J-39 on the parts listing. If its broke, it can be a real chore to remove the broken piece. Another thing to check is that the quill stop collar item J-36 is securely tightened to the quill. I would clean and relube all the items associated with the powerfeed assembly, and inspect and adjust the downfeed pressure. A little play here and a little play there all adds up, and a little crud or stickyness also makes for a a powerfeed that don';t work right. If you need an IPB on that mill its available on my site. Regards Visit my website: http://www.frugalmachinist.com Opinions expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy. |
#3
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bport -- powerfeed question
Good advice. I'd add that the bridgy powerdown really ain't meant as a power
down for drills of any size. Its a light weight unit meant for boring. Karl |
#4
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bport -- powerfeed question
Right Karl,
I seem to recall that mine is rated for only drilling 3/8 in steel. I never use it for that - preferring to save it what it really is meant for- boring as you said. Bob Swinney "Karl Townsend" wrote in message ink.net... Good advice. I'd add that the bridgy powerdown really ain't meant as a power down for drills of any size. Its a light weight unit meant for boring. Karl |
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bport -- powerfeed question
thanks for the tips everyone..
took the downfeed apart today. turns out it wasn't "kicking out" .. it was always engaged, but the gears (under the front cover, beneath the push/pull knob for direction) were loose. a few turns on the setscrews and i was in business. i also discovered that its not for drilling. at least not big holes. put a 20mm drill in there and.. well it bored about 2mm deep before i had to retighten all the setscrews again. i'll use it for boring, as recommended. just happy to have it working. next job: the broken ("clock") spring in the drill press handle. (sorry dont know the technical name) the spring was broken in two spots.. at the start and end (where the little holes are that fit over the pins).. i took the spring out, cut it a bit, punched new holes (that was tough!) and tried to recoil it. it snapped again, and i shortened it again. its probably 2" shorter on both ends. after fiddling for a few hours i gave up. i just couldnt wind the coil tight enough to get it back under the handle. finally, when i did, i couldn't get it to latch on the retents. as it is, i have to lift the quill by hand (lever) after drilling a hole.. it doesnt snap back up after i'm finished. tips? thanks again, -tony |
#6
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bport -- powerfeed question
"tony" wrote in message ... thanks for the tips everyone.. took the downfeed apart today. turns out it wasn't "kicking out" .. it was always engaged, but the gears (under the front cover, beneath the push/pull knob for direction) were loose. a few turns on the setscrews and i was in business. i also discovered that its not for drilling. at least not big holes. put a 20mm drill in there and.. well it bored about 2mm deep before i had to retighten all the setscrews again. i'll use it for boring, as recommended. just happy to have it working. next job: the broken ("clock") spring in the drill press handle. (sorry dont know the technical name) the spring was broken in two spots.. at the start and end (where the little holes are that fit over the pins).. i took the spring out, cut it a bit, punched new holes (that was tough!) and tried to recoil it. it snapped again, and i shortened it again. its probably 2" shorter on both ends. after fiddling for a few hours i gave up. i just couldnt wind the coil tight enough to get it back under the handle. finally, when i did, i couldn't get it to latch on the retents. as it is, i have to lift the quill by hand (lever) after drilling a hole.. it doesnt snap back up after i'm finished. tips? thanks again, -tony Tony, The spring should be set to balance the weight of the quill - it isn't intended to 'snap back up' Andrew Mawson |
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bport -- powerfeed question
"Andrew Mawson" wrote in message ... The spring should be set to balance the weight of the quill - it isn't intended to 'snap back up' Andrew Mawson Absolutely true! The "feel" of the quill will be compromised if the spring is not set properly. When you have the quill spring tension set right, you can "feel" what a small drill is doing. That can be very important if you do small work. I have mine set such that the weight of the handle when set forward will cause the quill to drop, or hold it in position if you move it to the rear. When doing small work, I even remove the little quill locking handle, which tends to add drag to the quill, costing me some of the feel. It's all in how you use your machine that makes the difference. Harold |
#8
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bport -- powerfeed question
good point. however, as it stands, i have no
spring counterbalancing the quill. releasing the quill lock causes it to drop pretty fast. until i either 1) get used to not having the quill return, or 2) find a way to fix it it'll be painful to watch expensive drills and mills drop dead onto the edges of workpieces. -tony |
#9
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bport -- powerfeed question
until i either 1) get used to not having the quill return, or 2) find a way to fix it In some older HSM publications a counterweight (Sash weight) was shown holding the quill in balance. Paul in AJ AZ |
#10
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bport -- powerfeed question
"tony" wrote in message news good point. however, as it stands, i have no spring counterbalancing the quill. releasing the quill lock causes it to drop pretty fast. until i either 1) get used to not having the quill return, or 2) find a way to fix it it'll be painful to watch expensive drills and mills drop dead onto the edges of workpieces. -tony Oh, yes, definitely. You'll need a spring, no getting around that. The quill is too heavy to not have the spring in place, and you risk damaging not only your cutting tools, but the machine and the parts you'll be making. Trying to salvage an old spring may not be a good idea, either. They break because they've been cycled through their useful life and will simply continue to break time and again. They're like garage door springs in that they experience fatigue through use. A new spring, regardless of cost, is in order. Good luck~ Harold |
#11
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bport -- powerfeed question
Bridgeport OEM parts,
http://www.hqtinc.com Good folks, fair prices, MUCH better than BPT. "tony" wrote in news:YaPhb.263762$R32.8564425 @news2.tin.it: thanks for the tips everyone.. took the downfeed apart today. turns out it wasn't "kicking out" .. it was always engaged, but the gears (under the front cover, beneath the push/pull knob for direction) were loose. a few turns on the setscrews and i was in business. i also discovered that its not for drilling. at least not big holes. put a 20mm drill in there and.. well it bored about 2mm deep before i had to retighten all the setscrews again. i'll use it for boring, as recommended. just happy to have it working. next job: the broken ("clock") spring in the drill press handle. (sorry dont know the technical name) the spring was broken in two spots.. at the start and end (where the little holes are that fit over the pins).. i took the spring out, cut it a bit, punched new holes (that was tough!) and tried to recoil it. it snapped again, and i shortened it again. its probably 2" shorter on both ends. after fiddling for a few hours i gave up. i just couldnt wind the coil tight enough to get it back under the handle. finally, when i did, i couldn't get it to latch on the retents. as it is, i have to lift the quill by hand (lever) after drilling a hole.. it doesnt snap back up after i'm finished. tips? thanks again, -tony |
#12
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bport -- powerfeed question
Don't confuse the quill of a milling machine with the quill of a drill
press. The mill's spring return is not designed to freely raise the quill (snap back) if you turn loose of the handle. The spring acts as an assist only, when raising the quill. In all likelihood if it returns as freely as a drill press this indicates the quill is seriously worn. You can purchase the housing and spring as a unit. Check with a machine tool supply house. Bob Swinney "tony" wrote in message ... thanks for the tips everyone.. took the downfeed apart today. turns out it wasn't "kicking out" .. it was always engaged, but the gears (under the front cover, beneath the push/pull knob for direction) were loose. a few turns on the setscrews and i was in business. i also discovered that its not for drilling. at least not big holes. put a 20mm drill in there and.. well it bored about 2mm deep before i had to retighten all the setscrews again. i'll use it for boring, as recommended. just happy to have it working. next job: the broken ("clock") spring in the drill press handle. (sorry dont know the technical name) the spring was broken in two spots.. at the start and end (where the little holes are that fit over the pins).. i took the spring out, cut it a bit, punched new holes (that was tough!) and tried to recoil it. it snapped again, and i shortened it again. its probably 2" shorter on both ends. after fiddling for a few hours i gave up. i just couldnt wind the coil tight enough to get it back under the handle. finally, when i did, i couldn't get it to latch on the retents. as it is, i have to lift the quill by hand (lever) after drilling a hole.. it doesnt snap back up after i'm finished. tips? thanks again, -tony |
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