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DT July 11th 10 01:51 AM

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


Ed Huntress July 11th 10 01:54 AM

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



Gunner Asch[_6_] July 11th 10 02:36 AM

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

Bob Engelhardt July 11th 10 04:07 AM

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

[email protected] July 11th 10 04:16 AM

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


Ignoramus7096 July 11th 10 04:33 AM

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


Wes[_5_] July 12th 10 10:11 AM

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

DT July 13th 10 02:04 AM

Made a special press for broaching
 
In article ,
says...

When you pushed the broach though, did you let up once or twice to allow the
broach to recenter itself?



I'm back, I was gone for a day. I did press it in stages to allow everything
to self center. Especially when you are broaching a thin part (mine was 5/8")
there is opportunity for the broach to tilt as only one or two teeth are
contacting at once.

This was a quicky solution and it worked, but it needs upgrading. I will add a
3" channel strongback at 90 degrees to the existing upright, that should
stiffen the press quite a bit. The way it was, every time a tooth cleared the
bottom of the workpiece, the flexing allowed the broach to jump ahead until
the next tooth engaged.

--
DT




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