Hi
Peter:
I
bought some steel that was too hard to saw. I built a big fire
in the back yard and annealed it for hours. When it cooled I
could cut it, but it was still tougher than mild steel.
You
could heat the chuck to soften it, but it would be best to re
harden it and touch up the ground surfaces.
Carl.
On 9/5/2023 12:50 PM, Peter Brooks
wrote:
toggle quoted message
Show quoted text
I tried to bore out and thread one of these to M14 x 1 - on a
Unimat 3 ! ?They are made of tough stuff. Wrecked an M14 tap,
although I had bored it generously.
(BTW surely by definition the minimum tap drill for M14 x 1 would
be 13mm? )
|
This chart is missing the M14x1mm which is 12.75mm
Get
toggle quoted message
Show quoted text
Drill sizes for metric tapping
From: Carl <carl.blum@...>
Sent: Tuesday, September 5, 2023 12:49 PM
To: [email protected] <[email protected]>; calciu1@... <calciu1@...>
Subject: Re: [Unimat] end mill holder
?
Hello:
I was told tap drills in metric are simple: screw size minus pitch, so M14 - 1mm = 13mm tap drill. 12.75 might be 100% thread, but not much stronger than 75%.
Carl.
On 9/5/2023 12:05 PM, Andrei wrote:
12.75 is the drill size for an M14 tap
I got one with a 8mm hole, ER-11, IIRC, with the intent to thread it M12x1 for my SL/DB machines. It's here somewhere! ;) IIRC, M14x1 needs a 13mm tap drill? I have a pair of very nice tungsten carbide 11mm tap drills for
my M12x1 stuff. Works nicely on hardened steel, which most of those things are. For my ER-25 Collet holder that I "made" from one of the longer shank collet chucks, that was a hard skin, but the tap had no problem once the tapping hole was drilled. Made it
pretty easy.?
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)?
|
Drill sizes for metric tapping
toggle quoted message
Show quoted text
From: Carl <carl.blum@...>
Sent: Tuesday, September 5, 2023 12:49 PM
To: [email protected] <[email protected]>; calciu1@... <calciu1@...>
Subject: Re: [Unimat] end mill holder
?
Hello:
I was told tap drills in metric are simple: screw size minus pitch, so M14 - 1mm = 13mm tap drill. 12.75 might be 100% thread, but not much stronger than 75%.
Carl.
On 9/5/2023 12:05 PM, Andrei wrote:
12.75 is the drill size for an M14 tap
I got one with a 8mm hole, ER-11, IIRC, with the intent to thread it M12x1 for my SL/DB machines. It's here somewhere! ;) IIRC, M14x1 needs a 13mm tap drill? I have a pair of very nice tungsten carbide 11mm tap drills for
my M12x1 stuff. Works nicely on hardened steel, which most of those things are. For my ER-25 Collet holder that I "made" from one of the longer shank collet chucks, that was a hard skin, but the tap had no problem once the tapping hole was drilled. Made it
pretty easy.?
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)?
|
I tried to bore out and thread one of these to M14 x 1 - on a Unimat 3 ! ?They are made of tough stuff. Wrecked an M14 tap, although I had bored it generously.
(BTW surely by definition the minimum tap drill for M14 x 1 would be 13mm? )
|
Hello:
I was
told tap drills in metric are simple: screw size minus pitch,
so M14 - 1mm = 13mm tap drill. 12.75 might be 100% thread, but
not much stronger than 75%.
Carl.
On 9/5/2023 12:05 PM, Andrei wrote:
toggle quoted message
Show quoted text
12.75 is the drill size for an M14 tap
I got one with a 8mm
hole, ER-11, IIRC, with the intent to thread it M12x1 for
my SL/DB machines. It's here somewhere! ;) IIRC, M14x1
needs a 13mm tap drill? I have a pair of very nice
tungsten carbide 11mm tap drills for my M12x1 stuff. Works
nicely on hardened steel, which most of those things are.
For my ER-25 Collet holder that I "made" from one of the
longer shank collet chucks, that was a hard skin, but the
tap had no problem once the tapping hole was drilled. Made
it pretty easy.?
Bill in OKC
William R.
Meyers, MSgt, USAF(Ret.)?
|
Ah, I understand! Hey, at least you didn't have to single-point that thread!
I think my best by date was about 38 years ago. But I have seen folks who should know say things that scare me. I'm 68 now. My dad had his first heart attack at age 50. And only missed I think 1 year of having one every year until his death at age 77. I've still (as of this moment, anyway) not had my first heart attack. It is potentially possible that I'm good for another 20 or 30? or even 40 years. And there is one guy who thinks that folks that are alive now may live as long as 1000 years. Maybe if I live that long I'll actually get to be a good machinist...
I wouldn't put any money on it, though!
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!
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 11:12:31 AM CDT, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
Yes I tapped the brass for the set screw, but I also cobbled the set screw together, not trivial on silver steel, which was the material closest to hand at the time. ?So I used a die for that - I die-ed it; fortunately the die won and the silver steel submitted! ?
(And yes, now ample opportunity to do cosmetic surgery on my knuckles if I use it carelessly! ?That’s okay though, I mean I broke two fingers severely, just falling down a 2 inch step soon after - I’m probably approaching my Best Before date.)
On 5 Sep 2023, at 16:51, Bill in OKC too via groups.io <wmrmeyers@...> wrote:
? Had to use a tap to thread the set screw hole. Possibly to thread the spindle end, too, though that can be single-point threaded if you have small enough tooling. IIRC dies are used to put external threads on a piece of material. Taps for internal threads. Unless he made his own set screw, that is. It could also be single-point threaded, but most likely threaded with a die in a home shop.?
I hesitate to say that no one single-point's small set screw holes, but I'm pretty sure it would be rare! Certainly beyond my skill levels!?
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!
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 10:27:53 AM CDT, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
“Die-ing”, not “tapping”. Wrong gender, so easy to confuse nowadays. On 5 Sep 2023, at 16:23, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
? I’m a certified beginner. ?This was one of the first successful things I made.
<image0.jpeg> <image1.jpeg> Yes I know the set screw arrangement is ‘unusual’, but I made it by tapping some silver steel / drill rod.
On 5 Sep 2023, at 16:01, Jeffrey Kropp <jeffreykropp1@...> wrote:
? ? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
Yes I tapped the brass for the set screw, but I also cobbled the set screw together, not trivial on silver steel, which was the material closest to hand at the time. ?So I used a die for that - I die-ed it; fortunately the die won and the silver steel submitted! ?
(And yes, now ample opportunity to do cosmetic surgery on my knuckles if I use it carelessly! ?That’s okay though, I mean I broke two fingers severely, just falling down a 2 inch step soon after - I’m probably approaching my Best Before date.)
toggle quoted message
Show quoted text
On 5 Sep 2023, at 16:51, Bill in OKC too via groups.io <wmrmeyers@...> wrote:
? Had to use a tap to thread the set screw hole. Possibly to thread the spindle end, too, though that can be single-point threaded if you have small enough tooling. IIRC dies are used to put external threads on a piece of material. Taps for internal threads. Unless he made his own set screw, that is. It could also be single-point threaded, but most likely threaded with a die in a home shop.?
I hesitate to say that no one single-point's small set screw holes, but I'm pretty sure it would be rare! Certainly beyond my skill levels!?
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!
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 10:27:53 AM CDT, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
“Die-ing”, not “tapping”. Wrong gender, so easy to confuse nowadays. On 5 Sep 2023, at 16:23, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
? I’m a certified beginner. ?This was one of the first successful things I made.
<image0.jpeg> <image1.jpeg> Yes I know the set screw arrangement is ‘unusual’, but I made it by tapping some silver steel / drill rod.
On 5 Sep 2023, at 16:01, Jeffrey Kropp <jeffreykropp1@...> wrote:
? ? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
toggle quoted message
Show quoted text
On Sep 5, 2023, at 5:27 PM, Mehmood via groups.io <mehmood.naqshbandi@...> wrote: ? “Die-ing”, not “tapping”. Wrong gender, so easy to confuse nowadays. On 5 Sep 2023, at 16:23, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
? I’m a certified beginner. ?This was one of the first successful things I made.
<image0.jpeg> <image1.jpeg> Yes I know the set screw arrangement is ‘unusual’, but I made it by tapping some silver steel / drill rod.
On 5 Sep 2023, at 16:01, Jeffrey Kropp <jeffreykropp1@...> wrote:
? ? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
12.75 is the drill size for an M14 tap
toggle quoted message
Show quoted text
I got one with a 8mm hole, ER-11, IIRC, with the intent to thread it M12x1 for my SL/DB machines. It's here somewhere! ;) IIRC, M14x1 needs a 13mm tap drill? I have a pair of very nice tungsten carbide 11mm tap drills for
my M12x1 stuff. Works nicely on hardened steel, which most of those things are. For my ER-25 Collet holder that I "made" from one of the longer shank collet chucks, that was a hard skin, but the tap had no problem once the tapping hole was drilled. Made it
pretty easy.?
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!
Improvise, Adapt, and Overcome.
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.
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 10:37:02 AM CDT, Andrei <calciu1@...> wrote:
You could buy one of these for 10=15 dollars and then tap the end for 14x1mm and you are done:?
|
|
Find many great new & used options and get the best deals for ER16 Collet Block Chuck Collet Holder Spindle Motor Shaft Clamping Tool Bar at the best online prices at eBay! Free shipping for many products!
www.ebay.com
|
|
I got one with a 8mm hole, ER-11, IIRC, with the intent to thread it M12x1 for my SL/DB machines. It's here somewhere! ;) IIRC, M14x1 needs a 13mm tap drill? I have a pair of very nice tungsten carbide 11mm tap drills for my M12x1 stuff. Works nicely on hardened steel, which most of those things are. For my ER-25 Collet holder that I "made" from one of the longer shank collet chucks, that was a hard skin, but the tap had no problem once the tapping hole was drilled. Made it pretty easy.?
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!
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 10:37:02 AM CDT, Andrei <calciu1@...> wrote:
You could buy one of these for 10=15 dollars and then tap the end for 14x1mm and you are done:?
|
|
Find many great new & used options and get the best deals for ER16 Collet Block Chuck Collet Holder Spindle Motor Shaft Clamping Tool Bar at the best online prices at eBay! Free shipping for many products!
www.ebay.com
|
|
Had to use a tap to thread the set screw hole. Possibly to thread the spindle end, too, though that can be single-point threaded if you have small enough tooling. IIRC dies are used to put external threads on a piece of material. Taps for internal threads. Unless he made his own set screw, that is. It could also be single-point threaded, but most likely threaded with a die in a home shop.?
I hesitate to say that no one single-point's small set screw holes, but I'm pretty sure it would be rare! Certainly beyond my skill levels!?
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!
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 10:27:53 AM CDT, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
“Die-ing”, not “tapping”. Wrong gender, so easy to confuse nowadays.
On 5 Sep 2023, at 16:23, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
? I’m a certified beginner. ?This was one of the first successful things I made.
<image0.jpeg> <image1.jpeg> Yes I know the set screw arrangement is ‘unusual’, but I made it by tapping some silver steel / drill rod.
On 5 Sep 2023, at 16:01, Jeffrey Kropp <jeffreykropp1@...> wrote:
? ? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
There is an old military maxim: If it's stupid, but it works, it ain't stupid!
Sure, you don't want to get your knuckles too close to it in use, but it works, right? That's all you need. And a regular 3-jaw chuck is also something you don't want to get your knuckles too close to! When you're not a beginner anymore, maybe you'll want to make one that you think is better, and it might well be better, but this one works! ;) Best is the enemy of good enough!
You could also try putting a shorter set/grub screw in it. ;) Might help, might not. ;)
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!
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 10:23:15 AM CDT, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
I’m a certified beginner. ?This was one of the first successful things I made.
  Yes I know the set screw arrangement is ‘unusual’, but I made it by tapping some silver steel / drill rod.
On 5 Sep 2023, at 16:01, Jeffrey Kropp <jeffreykropp1@...> wrote:
? ? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
jjg tools on ebay.co.uk offers an er16 collet holder in 12x1 and 14x1?
toggle quoted message
Show quoted text
On Sep 5, 2023, at 5:01 PM, Jeffrey Kropp <jeffreykropp1@...> wrote: ? ? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
You could buy one of these for 10=15 dollars and then tap the end for 14x1mm and you are done:?
|
|
Find many great new & used options and get the best deals for ER16 Collet Block Chuck Collet Holder Spindle Motor Shaft Clamping Tool Bar at the best online prices at eBay! Free shipping for many products!
www.ebay.com
|
|
“Die-ing”, not “tapping”. Wrong gender, so easy to confuse nowadays.
toggle quoted message
Show quoted text
On 5 Sep 2023, at 16:23, Mehmood via groups.io <mehmood.naqshbandi@...> wrote:
? I’m a certified beginner. ?This was one of the first successful things I made.
<image0.jpeg> <image1.jpeg> Yes I know the set screw arrangement is ‘unusual’, but I made it by tapping some silver steel / drill rod.
On 5 Sep 2023, at 16:01, Jeffrey Kropp <jeffreykropp1@...> wrote:
? ? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
I’m a certified beginner. ?This was one of the first successful things I made.
  Yes I know the set screw arrangement is ‘unusual’, but I made it by tapping some silver steel / drill rod.
toggle quoted message
Show quoted text
On 5 Sep 2023, at 16:01, Jeffrey Kropp <jeffreykropp1@...> wrote:
? ? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
theres one on ebay with collets -?
------ Original Message ------
Date 05/09/2023 16:00:41
Subject Re: [Unimat] end mill holder
? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
? ? Mert offered partially-machined end mill holders.
Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
Can you get away with using a drill chuck to hold an end mill? Probably. Maybe. Sometimes. :) On a Unimat the forces are likely to be lower than on larger machines. BUT! The end mills you're using on a Unimat are likely to be small & fragile, so more likely to be damaged. Pull-out is probably the most likely problem. The forces applied pull the cutter into the material being cut, which can overload the cutter, pull the material out of the clamps, and shatter the end mill.?
Drill chucks make lousy end mill holders. They aren't really even all that good at holding drill bits. They grip along a narrow band in 3 locations 120 degrees apart with a curved surface that is very likely to slip. How many times have you seen a drill bit that has spun in the chuck? The shank gets torn up and can no longer get anything like concentricity.?
The fingers used in drill chucks to grip the drill bit shank are hardened, and frequently slip on a drill bit with a relatively short shank. They're used because they easily adjust to any size shank within their range, not because they grip reliably. Can you imagine buying a set of collets made to hold drill bits in .001" increments? Or less? Yikes! You'd need a set of nearly 1000 collets...?
End mills have hardened shanks and a drill chuck cannot reliably grip them. Weldon shank end mills were invented because straight shank end mills can still slip even in? properly sized end mill holders? or collets due to the forces involved. And even Weldon shank end mills in proper holders can be broken.?
There are tables that show the appropriate sizes for Weldon shank end mills & end mill holders, and they're not all that difficult to make. End mills come with a limited number of standardized shanks, so you only need a few end mill holders. Weldon shanks aren't perfect. They pushed the cutter off-center, and off balance. And there are probably dozens of other systems for holding end mills, but not all of them scale well for a Unimat.?
I have personally pulled a Weldon shank 1/2" end mill out of the holder and destroyed it and my part, on a Bridgeport-class milling machine. Was not quite spectacular, but was startling! :) Unimats aren't nearly as powerful, and you're unlikely to be using a half-inch end mill on one, but an eighth-inch end mill isn't nearly as strong and the parts you're making are probably much easier to destroy.?
And making tooling like end mill holders is good practice for more complex projects.
OK. Off my soap box now! ;)
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!
Expect in one hand, expectorate in the other. See which one gets full first.
On Tuesday, September 5, 2023 at 06:43:06 AM CDT, Peter Brooks <peter@...> wrote:
Or of course a drill chuck. Depends what you are trying to do and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier Unimats) are probably easier to find than collet chucks with those threadings.
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Hi
Gang:
It is
easy to drill and tap a drill chuck to fit Unimats, I've done
it to chucks up to 1/2" capacity. I mostly use the 1/4" chuck
converted in 1973.
While
you can hold a milling cutter in a drill chuck, you will not
come close to cutting capacity of the cutter. Most likely the
cutter will move or even be ejected by cutting forces.
Much
better is to make solid cutter holders from 3/4" bar stock.
Drill and tap to match the spindle then bore for your cutter
and add a set screw to clamp the cutter. I have 3/8" and 1/2"
holders that work fine.
Carl.
On 9/5/2023 7:43 AM, Peter Brooks
wrote:
toggle quoted message
Show quoted text
Or of course a drill chuck. Depends what you are trying to do
and how accurate you need to be.
Drill chucks to fit M14 x 1 (Unimat 3 / 4) or M12 x 1 (earlier
Unimats) are probably easier to find than collet chucks with
those threadings.
|
Carl
Bill in OKC too
John Entwistle