I'm getting ready to broach my first keyway with an actual broach . My question is about the shims , and how thick they need to be .
Measuring the difference between the first and last tooth on the
broach I get .062" and I'm wondering if that is the correct thickness
for the shims .
On 26/03/2024 16:42, Snag wrote:
I'm getting ready to broach my first keyway with an actual broach . My
question is about the shims , and how thick they need to be .
Measuring the difference between the first and last tooth on the
broach I get .062" and I'm wondering if that is the correct thickness
for the shims .
Is it a shop made broach or bought. All my Dumont broaches come with appropriate shims to cut the keyway to the correct depth.
On 3/26/2024 12:58 PM, David Billington wrote:
On 26/03/2024 16:42, Snag wrote:
I'm getting ready to broach my first keyway with an actual broach .
My question is about the shims , and how thick they need to be .
Measuring the difference between the first and last tooth on the
broach I get .062" and I'm wondering if that is the correct thickness
for the shims .
Is it a shop made broach or bought. All my Dumont broaches come with
appropriate shims to cut the keyway to the correct depth.
It's a couple of broaches only from eBay . I machined a guide slug
for it from some 416 SS I bought to "have some on hand in case I need
it" and pushed it with my 12/20* ton HF press .
.050" galvanized sheet I have on hand (being a Pack Rat is often a Good Thing) and it worked out quite well . I'll never broach another keyway
on the lathe ...
*12 ton frame with a 20 ton air operated jack on it . I have beefed
up the frame where it was necessary .
"Snag" wrote in message news:ututu3$1u2oj$1@dont-email.me...
I'm getting ready to broach my first keyway with an actual broach .
My question is about the shims , and how thick they need to be .
Measuring the difference between the first and last tooth on the broach
I get .062" and I'm wondering if that is the correct thickness for the
shims .
Snag
-----------------------------
My 3/16" keyway broach came with an 0.050" shim. For the others I shear strips of scrap sheetmetal and add one between passes until the key
fits. My guide bushings are all shop-made to eyeballed depth.
Thinner shims leave less unsupported broach, but if the shim is too thin
to hold the bend the broach may pull it through.
On 3/26/2024 12:58 PM, David Billington wrote:
On 26/03/2024 16:42, Snag wrote:
I'm getting ready to broach my first keyway with an actual broach .
My question is about the shims , and how thick they need to be .
Measuring the difference between the first and last tooth on the
broach I get .062" and I'm wondering if that is the correct
thickness for the shims .
Is it a shop made broach or bought. All my Dumont broaches come with
appropriate shims to cut the keyway to the correct depth.
It's a couple of broaches only from eBay . I machined a guide slug
for it from some 416 SS I bought to "have some on hand in case I need
it" and pushed it with my 12/20* ton HF press . I made shims from some .050" galvanized sheet I have on hand (being a Pack Rat is often a
Good Thing) and it worked out quite well . I'll never broach another
keyway on the lathe ...
*12 ton frame with a 20 ton air operated jack on it . I have beefed
up the frame where it was necessary .
On 26/03/2024 20:40, Snag wrote:
On 3/26/2024 12:58 PM, David Billington wrote:
On 26/03/2024 16:42, Snag wrote:
I'm getting ready to broach my first keyway with an actual broach .
My question is about the shims , and how thick they need to be .
Measuring the difference between the first and last tooth on the
broach I get .062" and I'm wondering if that is the correct
thickness for the shims .
Is it a shop made broach or bought. All my Dumont broaches come with
appropriate shims to cut the keyway to the correct depth.
It's a couple of broaches only from eBay . I machined a guide slug
for it from some 416 SS I bought to "have some on hand in case I need
it" and pushed it with my 12/20* ton HF press . I made shims from some
.050" galvanized sheet I have on hand (being a Pack Rat is often a
Good Thing) and it worked out quite well . I'll never broach another
keyway on the lathe ...
*12 ton frame with a 20 ton air operated jack on it . I have beefed
up the frame where it was necessary .
Maybe some of the information in the Dumont catalogue would be of use.
It gives the broach lengths and the thickness and number of shims
required. https://kar.ca/pdf/catalog/en/Dumont_Catalog.pdf
On 3/27/2024 9:53 AM, David Billington wrote:
On 26/03/2024 20:40, Snag wrote:
On 3/26/2024 12:58 PM, David Billington wrote:
On 26/03/2024 16:42, Snag wrote:
I'm getting ready to broach my first keyway with an actual broach
. My question is about the shims , and how thick they need to be .
Measuring the difference between the first and last tooth on the
broach I get .062" and I'm wondering if that is the correct
thickness for the shims .
Is it a shop made broach or bought. All my Dumont broaches come
with appropriate shims to cut the keyway to the correct depth.
It's a couple of broaches only from eBay . I machined a guide slug
for it from some 416 SS I bought to "have some on hand in case I
need it" and pushed it with my 12/20* ton HF press . I made shims
from some .050" galvanized sheet I have on hand (being a Pack Rat
is often a Good Thing) and it worked out quite well . I'll never
broach another keyway on the lathe ...
*12 ton frame with a 20 ton air operated jack on it . I have
beefed up the frame where it was necessary .
Maybe some of the information in the Dumont catalogue would be of
use. It gives the broach lengths and the thickness and number of
shims required. https://kar.ca/pdf/catalog/en/Dumont_Catalog.pdf
I figure the shim should be the same thickness as the difference
between the first and last tooth - mine measure .062 . This will keep
the "pilot" on the end in contact with the bottom of the groove being
cut . I noticed a variation in the depth on that keyway I cut
yesterday ... I think because the broach was not bottomed out in the
groove in the pilot bushing .
On 27/03/2024 17:25, Snag wrote:
On 3/27/2024 9:53 AM, David Billington wrote:
On 26/03/2024 20:40, Snag wrote:
On 3/26/2024 12:58 PM, David Billington wrote:
On 26/03/2024 16:42, Snag wrote:
I'm getting ready to broach my first keyway with an actual broach
. My question is about the shims , and how thick they need to be . >>>>>> Measuring the difference between the first and last tooth on the
broach I get .062" and I'm wondering if that is the correct
thickness for the shims .
Is it a shop made broach or bought. All my Dumont broaches come
with appropriate shims to cut the keyway to the correct depth.
It's a couple of broaches only from eBay . I machined a guide slug
for it from some 416 SS I bought to "have some on hand in case I
need it" and pushed it with my 12/20* ton HF press . I made shims
from some .050" galvanized sheet I have on hand (being a Pack Rat
is often a Good Thing) and it worked out quite well . I'll never
broach another keyway on the lathe ...
*12 ton frame with a 20 ton air operated jack on it . I have
beefed up the frame where it was necessary .
Maybe some of the information in the Dumont catalogue would be of
use. It gives the broach lengths and the thickness and number of
shims required. https://kar.ca/pdf/catalog/en/Dumont_Catalog.pdf
I figure the shim should be the same thickness as the difference
between the first and last tooth - mine measure .062 . This will keep
the "pilot" on the end in contact with the bottom of the groove being
cut . I noticed a variation in the depth on that keyway I cut
yesterday ... I think because the broach was not bottomed out in the
groove in the pilot bushing .
I've seen that with mine before like yesterday where the top of the
broach was leaning towards me a bit, cutting edges forward, so I
corrected it for the second pass for a 4mm key. I'll check my broaches tomorrow and see how the shim thickness correlates to the height
increase along the broach and report back.
On 3/27/2024 12:42 PM, David Billington wrote:
On 27/03/2024 17:25, Snag wrote:
On 3/27/2024 9:53 AM, David Billington wrote:
On 26/03/2024 20:40, Snag wrote:
On 3/26/2024 12:58 PM, David Billington wrote:
On 26/03/2024 16:42, Snag wrote:
I'm getting ready to broach my first keyway with an actual
broach . My question is about the shims , and how thick they
need to be . Measuring the difference between the first and last >>>>>>> tooth on the broach I get .062" and I'm wondering if that is the >>>>>>> correct thickness for the shims .
Is it a shop made broach or bought. All my Dumont broaches come
with appropriate shims to cut the keyway to the correct depth.
It's a couple of broaches only from eBay . I machined a guide
slug for it from some 416 SS I bought to "have some on hand in
case I need it" and pushed it with my 12/20* ton HF press . I made
shims from some .050" galvanized sheet I have on hand (being a
Pack Rat is often a Good Thing) and it worked out quite well .
I'll never broach another keyway on the lathe ...
*12 ton frame with a 20 ton air operated jack on it . I have
beefed up the frame where it was necessary .
Maybe some of the information in the Dumont catalogue would be of
use. It gives the broach lengths and the thickness and number of
shims required. https://kar.ca/pdf/catalog/en/Dumont_Catalog.pdf
I figure the shim should be the same thickness as the difference
between the first and last tooth - mine measure .062 . This will
keep the "pilot" on the end in contact with the bottom of the groove
being cut . I noticed a variation in the depth on that keyway I cut
yesterday ... I think because the broach was not bottomed out in the
groove in the pilot bushing .
I've seen that with mine before like yesterday where the top of the
broach was leaning towards me a bit, cutting edges forward, so I
corrected it for the second pass for a 4mm key. I'll check my
broaches tomorrow and see how the shim thickness correlates to the
height increase along the broach and report back.
This was a case of I started the cut on the lathe , cranking the
carriage forward and back . I think the taper would have
self-corrected if I'd used a .062" shim instead of the .050" .
On 27/03/2024 18:55, Snag wrote:
On 3/27/2024 12:42 PM, David Billington wrote:
On 27/03/2024 17:25, Snag wrote:
On 3/27/2024 9:53 AM, David Billington wrote:
On 26/03/2024 20:40, Snag wrote:
On 3/26/2024 12:58 PM, David Billington wrote:
On 26/03/2024 16:42, Snag wrote:
I'm getting ready to broach my first keyway with an actual
broach . My question is about the shims , and how thick they
need to be . Measuring the difference between the first and last >>>>>>>> tooth on the broach I get .062" and I'm wondering if that is the >>>>>>>> correct thickness for the shims .
Is it a shop made broach or bought. All my Dumont broaches come
with appropriate shims to cut the keyway to the correct depth.
It's a couple of broaches only from eBay . I machined a guide
slug for it from some 416 SS I bought to "have some on hand in
case I need it" and pushed it with my 12/20* ton HF press . I made >>>>>> shims from some .050" galvanized sheet I have on hand (being a
Pack Rat is often a Good Thing) and it worked out quite well .
I'll never broach another keyway on the lathe ...
*12 ton frame with a 20 ton air operated jack on it . I have
beefed up the frame where it was necessary .
Maybe some of the information in the Dumont catalogue would be of
use. It gives the broach lengths and the thickness and number of
shims required. https://kar.ca/pdf/catalog/en/Dumont_Catalog.pdf
I figure the shim should be the same thickness as the difference
between the first and last tooth - mine measure .062 . This will
keep the "pilot" on the end in contact with the bottom of the groove
being cut . I noticed a variation in the depth on that keyway I cut
yesterday ... I think because the broach was not bottomed out in the
groove in the pilot bushing .
I've seen that with mine before like yesterday where the top of the
broach was leaning towards me a bit, cutting edges forward, so I
corrected it for the second pass for a 4mm key. I'll check my
broaches tomorrow and see how the shim thickness correlates to the
height increase along the broach and report back.
This was a case of I started the cut on the lathe , cranking the
carriage forward and back . I think the taper would have
self-corrected if I'd used a .062" shim instead of the .050" .
This is what I measured.
Broach list Dumont No 10 set
Size Start End Diff Teeth /Tooth Shim 1/8" 0.390 0.421 0.031 16 0.0021 0.031 x 1
3/16" 0.377 0.429 0.052 16 0.0035 0.050 x 1
1/4" 0.587 0.651 0.064 22 0.0030 0.062 x 1
3/8" 0.569 0.633 0.064 22 0.0030 0.062 x 2
The /Tooth is Diff /(Teeth - 1) . Looks like your original assumption
about the shim thickness is correct.
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