Date
1 - 19 of 19
Not a Lathe Question, but I figured one of you folks would know
|
Retired Gunsmith
I have a Shaping Head for my Bridgeport Mill. I am making a Detachable Magazine Bottom Metal for a Weatherby Mark V and I need to broach out the magwell for the magazine. Depth is about 3 inches, as I have not sorted out stop surfaces or magazine retainer yet. I am getting ALOT of tool deflection, and while a slight taper would be useful, this is WAAAYY too much. Can someone provide input on a properly shaped broaching tool? I am currently using a 3/8" square lathe tool, with a ground radius cutting surface on the tip. It was my best guess, and has worked in the past on smaller (shorter) broaching.
Can anyone assist? |
|
|
|
Ondrej Krejci <okrejci@...>
Hello, Does the tool have enough relief? Rectangular bits may be more sturdy. A picture or two would be better for a diagnosis. OK
On Saturday, October 15, 2022 at 12:10:00 PM EDT, Retired Gunsmith via groups.io <ask_derrick@...> wrote:
I have a Shaping Head for my Bridgeport Mill. I am making a Detachable Magazine Bottom Metal for a Weatherby Mark V and I need to broach out the magwell for the magazine. Depth is about 3 inches, as I have not sorted out stop surfaces or magazine retainer yet. I am getting ALOT of tool deflection, and while a slight taper would be useful, this is WAAAYY too much. Can someone provide input on a properly shaped broaching tool? I am currently using a 3/8" square lathe tool, with a ground radius cutting surface on the tip. It was my best guess, and has worked in the past on smaller (shorter) broaching. Can anyone assist? |
|
|
|
Retired Gunsmith
Here are photos of cutter and shaping head. I have torn down setup until I can get tooling resolved, so I can't show what operation looked like. I ground reliefs on back and sides to keep cutter from rubbing on workpiece after taper appeared, but it didn't help.
    Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
|
|
|
|
It seems to me that taper will not be due to the tool itself deflecting - Why would it deflect more at a different part of the cutting stroke than at another? I feel that the place to look is the tool support structure, particularly the variable length part beyond the last fixed support. Maybe that isn't stiff? Also can we be clear on slotting v broaching? A broach is essentially a guided, tapered file. They are best used with a parallel sliding surface on the back unless you are cutting equally all around, such as turning a circular hole into a square hole. Slotting is to all intents and purposes vertical shaping. You can cut a keyway in a hole on any of a broach, slotter or shaper with the right setup. Can you correct for the tapering action by tilting the hole by the same amount? Eddie (I don't shoot, but happy to contribute ideas that can also be used in other applications.)
|
|
|
|
Retired Gunsmith
Here is my part. I drilled holes thru to remove bulk of material and then joined them with an endmill. Now I need to establish final dimensions and shape/broach corners square. I have over .050 taper on each side (top of part is .950 and bottom of opening is .820)
NOTE-
I guess the best description would be vertical shaping. I have always used broaching and shaping interchangeably, because I haven't done either very often. I have had the shaping head for 40 years, and this is the fourth time I have ever used it. I don't have much experience, and hoped the group could add to it.
  Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
|
|
|
|
wmrmeyers@gmail.com
I am not a machinist, though I have some recent training to become one. I'm also not an expert with shapers. Not a gunsmith either though I dream about it sometimes. :) That is how I came to buy my 1st small lathe. I have been a voracious reader on these subjects for some years. You have a lot of stick-out for your cutting tool. Looks like it's relatively narrow, too. Maybe 1/4" to 3/8" cross-section on the tools? You're probably getting a lot of flex in the cutter. Try something larger if you can? Maybe 7/16-5/8" square stock, or as another poster suggested, rectangular stock for your tool? Same width but deeper depth? It will be stiffer and not deflect so much if you could use tooling that was 1/4"x5/16", even. Might be enough, though larger in both dimensions would work a little better for every step larger you can get. Or just take very shallow cuts repeated a lot of times without any feed until you get the straight walls you need? I have a couple forgings with no holes whatsoever, so I'd be interested in seeing how you do it. I don't have a Bridgeport with a slotter/shaper head, but do have a small shaper. It could be done with a file (set of files, really) by someone more skilled than I am. You could even make a properly-sized broach. :) Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement. SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Saturday, October 15, 2022 at 02:25:51 PM CDT, Retired Gunsmith via groups.io <ask_derrick@...> wrote:
Here are photos of cutter and shaping head. I have torn down setup until I can get tooling resolved, so I can't show what operation looked like. I ground reliefs on back and sides to keep cutter from rubbing on workpiece after taper appeared, but it didn't help.
    Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
|
|
|
|
Andrei
Pictures are not the greatest. Is that a parting tool bit sticking out so far? Can you bring it in more?
On my 7" shaper the bits are 7/16". Larger shapers can go to 1 inch tool bits or even more for those 36" monsters.
I have never seen up close a Bridgeport shaping adapter, but maybe it is meant to use the same size bits?
From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of wmrmeyers@... <wmrmeyers@...>
Sent: Saturday, October 15, 2022 10:51 PM To: SouthBendLathe@groups.io <SouthBendLathe@groups.io> Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know I am not a machinist, though I have some recent training to become one. I'm also not an expert with shapers. Not a gunsmith either though I dream about it sometimes. :) That is how I came to buy my 1st small lathe. I have been a voracious reader on these
subjects for some years. You have a lot of stick-out for your cutting tool. Looks like it's relatively narrow, too. Maybe 1/4" to 3/8" cross-section on the tools? You're probably getting a lot of flex in the cutter. Try something larger if you can? Maybe 7/16-5/8"
square stock, or as another poster suggested, rectangular stock for your tool? Same width but deeper depth? It will be stiffer and not deflect so much if you could use tooling that was 1/4"x5/16", even. Might be enough, though larger in both dimensions would
work a little better for every step larger you can get. Or just take very shallow cuts repeated a lot of times without any feed until you get the straight walls you need?
I have a couple forgings with no holes whatsoever, so I'd be interested in seeing how you do it. I don't have a Bridgeport with a slotter/shaper head, but do have a small shaper. It could be done with a file (set of files, really) by someone more skilled
than I am.
You could even make a properly-sized broach. :)
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by:
Good judgement comes from experience. Experience comes from bad judgement.
SEMPER GUMBY!
Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better On Saturday, October 15, 2022 at 02:25:51 PM CDT, Retired Gunsmith via groups.io <ask_derrick@...> wrote:
Here are photos of cutter and shaping head. I have torn down setup until I can get tooling resolved, so I can't show what operation looked like. I ground reliefs on back and sides to keep cutter from rubbing
on workpiece after taper appeared, but it didn't help.
    Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
|
|
|
|
Howdy, That 45° "hook" angle is definitely part of the problem. 5° to 20° is normal for ferrous materials. You´ll need some clearance behind the cutting edge: either by grinding up to where the bit seats in the holder or putting a thin shim at the top of the bit, opposite the upper set screw to cock it slightly forward, into the cut. |
|
|
|
Mike Poore
I assume you have confirmed that the shaper head ways are tight and
that the part is not moving? You might find the books such as "How
to Run a Shaper" helpful on grinding a proper tool. Lighter cuts
could help some as well.
toggle quoted message
Show quoted text
On 10/15/2022 12:09 PM, Retired
Gunsmith via groups.io wrote:
I have a Shaping Head for my Bridgeport Mill. I am making a Detachable Magazine Bottom Metal for a Weatherby Mark V and I need to broach out the magwell for the magazine. Depth is about 3 inches, as I have not sorted out stop surfaces or magazine retainer yet. I am getting ALOT of tool deflection, and while a slight taper would be useful, this is WAAAYY too much. Can someone provide input on a properly shaped broaching tool? I am currently using a 3/8" square lathe tool, with a ground radius cutting surface on the tip. It was my best guess, and has worked in the past on smaller (shorter) broaching. |
|
|
|
Scott Highton
That tool seems to be extended out quite far given its (relatively) small size. That alone would allow for lots of flex as it’s cutting.
Keep the cutting tool as short as possible. The shaping head itself seems to be tall and thin, which could contribute to additional flexing. Take the smallest (thinnest) cuts you can – i.e. general machining practices for best quality. Scott |
|
|
|
mike allen
Like others have said , shortest amount of stickout & a larger
toggle quoted message
Show quoted text
tool bit . Whats the largest tool bit size the attachment can use ? Heres one place that I buy cutters from & you can get a idea of what size bits are out there , I have had no problem with any of the tool bits I've bought from these folks . They have them in all sorts of lengths . Rectangle bits https://www.msdiscounttool.com/catalog/index.php?cPath=3437_1_4218_4219_4220 Square bits https://www.msdiscounttool.com/catalog/index.php?cPath=4222 animal On 10/16/2022 11:54 AM, Scott Highton wrote:
That tool seems to be extended out quite far given its (relatively) small size. That alone would allow for lots of flex as it’s cutting. |
|
|
|
Retired Gunsmith
Tool is 3/8 square. Largest the holder will accommodate without modification. Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
-----Original Message-----
From: mike allen <animal@...> To: SouthBendLathe@groups.io Sent: Sun, Oct 16, 2022 12:21 pm Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know Like others have said , shortest amount of stickout & a larger
tool bit . Whats the largest tool bit size the attachment can use ? Heres one place that I buy cutters from & you can get a idea of what size bits are out there , I have had no problem with any of the tool bits I've bought from these folks . They have them in all sorts of lengths . Rectangle bits https://www.msdiscounttool.com/catalog/index.php?cPath=3437_1_4218_4219_4220 Square bits https://www.msdiscounttool.com/catalog/index.php?cPath=4222 animal On 10/16/2022 11:54 AM, Scott Highton wrote: > That tool seems to be extended out quite far given its (relatively) small size. That alone would allow for lots of flex as it’s cutting. > > Keep the cutting tool as short as possible. The shaping head itself seems to be tall and thin, which could contribute to additional flexing. > > Take the smallest (thinnest) cuts you can – i.e. general machining practices for best quality. > > > Scott > > > > |
|
|
|
Retired Gunsmith
Workpiece is almost 3 inches tall. Tool needs to be that long to go thru the magwell.
I have thought about working in halves, i.e. 1 1/2 inch stroke from top and bottom, but was hoping to find a way to do it all from the same end. Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
-----Original Message-----
From: Scott Highton <scott@...> To: SouthBendLathe@groups.io Sent: Sun, Oct 16, 2022 11:54 am Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know That tool seems to be extended out quite far given its (relatively) small size. That alone would allow for lots of flex as it’s cutting.
Keep the cutting tool as short as possible. The shaping head itself seems to be tall and thin, which could contribute to additional flexing.
Take the smallest (thinnest) cuts you can – i.e. general machining practices for best quality.
Scott
|
|
|
|
Try a less acute angle on the cutting edge, and take tiny cuts, and you should be able to get it. Or grind a 3/8" square shank in a 7/16" or 1/2" cutting tool, and still take tiny bites. :) The larger tool will get you more reach and a slightly stiffer tool. Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement. SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Sunday, October 16, 2022 at 02:28:44 PM CDT, Retired Gunsmith via groups.io <ask_derrick@...> wrote:
Workpiece is almost 3 inches tall. Tool needs to be that long to go thru the magwell.
I have thought about working in halves, i.e. 1 1/2 inch stroke from top and bottom, but was hoping to find a way to do it all from the same end. Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
-----Original Message-----
From: Scott Highton <scott@...> To: SouthBendLathe@groups.io Sent: Sun, Oct 16, 2022 11:54 am Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know That tool seems to be extended out quite far given its (relatively) small size. That alone would allow for lots of flex as it’s cutting.
Keep the cutting tool as short as possible. The shaping head itself seems to be tall and thin, which could contribute to additional flexing.
Take the smallest (thinnest) cuts you can – i.e. general machining practices for best quality.
Scott
|
|
|
|
Retired Gunsmith
Spent the weekend on research.
Seems my shaping head has a home made tool holder (that came with it).
Original setup had Bridgeport proprietary tooling on 5/8 shanks..
Anybody have any of these to sell?
I found old posts on EBAY, but no current ones.
 Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
-----Original Message-----
From: Bill in OKC too via groups.io <wmrmeyers@...> To: SouthBendLathe@groups.io Sent: Sun, Oct 16, 2022 1:23 pm Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know Try a less acute angle on the cutting edge, and take tiny cuts, and you should be able to get it. Or grind a 3/8" square shank in a 7/16" or 1/2" cutting tool, and still take tiny bites. :) The larger tool will get you more reach and a slightly stiffer tool.
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by:
Good judgement comes from experience. Experience comes from bad judgement.
SEMPER GUMBY!
Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Sunday, October 16, 2022 at 02:28:44 PM CDT, Retired Gunsmith via groups.io <ask_derrick@...> wrote:
Workpiece is almost 3 inches tall. Tool needs to be that long to go thru the magwell.
I have thought about working in halves, i.e. 1 1/2 inch stroke from top and bottom, but was hoping to find a way to do it all from the same end.
Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
-----Original Message-----
From: Scott Highton <scott@...> To: SouthBendLathe@groups.io Sent: Sun, Oct 16, 2022 11:54 am Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know That tool seems to be extended out quite far given its (relatively) small size. That alone would allow for lots of flex as it’s cutting.
Keep the cutting tool as short as possible. The shaping head itself seems to be tall and thin, which could contribute to additional flexing.
Take the smallest (thinnest) cuts you can – i.e. general machining practices for best quality.
Scott
|
|
|
|
m. allan noah
Make one from a piece of bar, and a cross hole for a small piece of HSS. allan On Mon, Oct 17, 2022 at 3:19 PM Retired Gunsmith via groups.io <ask_derrick=aol.com@groups.io> wrote:
-- "well, I stand up next to a mountain- and I chop it down with the edge of my hand" |
|
|
|
mike allen
You might ask over on the forsale/wanted Practical
Machinist forum animal On 10/17/2022 12:19 PM, Retired
Gunsmith via groups.io wrote:
|
|
|
|
Andrei
If you have 5/8 to work with, maybe you can use 7/16 tool bits for extra beefiness
From: SouthBendLathe@groups.io <SouthBendLathe@groups.io> on behalf of m. allan noah <kitno455@...>
Sent: Monday, October 17, 2022 3:26 PM To: SouthBendLathe@groups.io <SouthBendLathe@groups.io> Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know Make one from a piece of bar, and a cross hole for a small piece of HSS.
allan
On Mon, Oct 17, 2022 at 3:19 PM Retired Gunsmith via
groups.io <ask_derrick=aol.com@groups.io> wrote:
-- "well, I stand up next to a mountain- and I chop it down with the edge of my hand"
|
|
|
|
Ondrej Krejci <okrejci@...>
Sorry, I left all those 5/8" shank bits at Flowserve in 2005 when I quit. But you can see how they are generally designed, so you can make some from solid HSS or just HRS and weld on some Stellite at the tips. Enjoy, OK
On Monday, October 17, 2022 at 03:19:56 PM EDT, Retired Gunsmith via groups.io <ask_derrick@...> wrote:
Spent the weekend on research.
Seems my shaping head has a home made tool holder (that came with it).
Original setup had Bridgeport proprietary tooling on 5/8 shanks..
Anybody have any of these to sell?
I found old posts on EBAY, but no current ones.
Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
-----Original Message-----
From: Bill in OKC too via groups.io <wmrmeyers@...> To: SouthBendLathe@groups.io Sent: Sun, Oct 16, 2022 1:23 pm Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know Try a less acute angle on the cutting edge, and take tiny cuts, and you should be able to get it. Or grind a 3/8" square shank in a 7/16" or 1/2" cutting tool, and still take tiny bites. :) The larger tool will get you more reach and a slightly stiffer tool.
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by:
Good judgement comes from experience. Experience comes from bad judgement.
SEMPER GUMBY!
Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Sunday, October 16, 2022 at 02:28:44 PM CDT, Retired Gunsmith via groups.io <ask_derrick@...> wrote:
Workpiece is almost 3 inches tall. Tool needs to be that long to go thru the magwell.
I have thought about working in halves, i.e. 1 1/2 inch stroke from top and bottom, but was hoping to find a way to do it all from the same end.
Thanx and Good Shootin'
Derrick Martin
ask_derrick@...
-----Original Message-----
From: Scott Highton <scott@...> To: SouthBendLathe@groups.io Sent: Sun, Oct 16, 2022 11:54 am Subject: Re: [SouthBendLathe] Not a Lathe Question, but I figured one of you folks would know That tool seems to be extended out quite far given its (relatively) small size. That alone would allow for lots of flex as it’s cutting.
Keep the cutting tool as short as possible. The shaping head itself seems to be tall and thin, which could contribute to additional flexing.
Take the smallest (thinnest) cuts you can – i.e. general machining practices for best quality.
Scott
|
|
|
