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

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


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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

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

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

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

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

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

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

bport -- powerfeed question
 

"tony" wrote in message
...
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

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

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