I'm trying to do some DC/pulse testing on a phemt, partly to validate a Spice model. The RF data sheets are mostly useless for time domain use. The danged thing keeps oscillating on a regular surfmount adapter, and that makes measurements weird. So I hacked this. https://www.dropbox.com/s/s8i90zlrgxdrzu2/Phemt_Dremel_1.jpg?raw=1 SOT-143 is about my resolution limit for handheld dremeling. It probably doesn't need the vias... the edge launch SMA connectors connect both sides pretty well. Our general impression is that you can drive these things really hard and get unexpected results, at suitably low duty cycles. We take Abs Max ratings as polite suggestions. -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
dremel phemt
Started by ●July 4, 2021
Reply by ●July 4, 20212021-07-04
On Sun, 04 Jul 2021 14:23:41 -0700, jlarkin@highlandsniptechnology.com wrote:>I'm trying to do some DC/pulse testing on a phemt, partly to validate >a Spice model. The RF data sheets are mostly useless for time domain >use. > >The danged thing keeps oscillating on a regular surfmount adapter, and >that makes measurements weird. So I hacked this. > >https://www.dropbox.com/s/s8i90zlrgxdrzu2/Phemt_Dremel_1.jpg?raw=1 > >SOT-143 is about my resolution limit for handheld dremeling. It >probably doesn't need the vias... the edge launch SMA connectors >connect both sides pretty well. > >Our general impression is that you can drive these things really hard >and get unexpected results, at suitably low duty cycles. We take Abs >Max ratings as polite suggestions.Shot with the Samsung phone. There's a selfie in there! -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Reply by ●July 5, 20212021-07-05
On 7/4/2021 4:42 PM, jlarkin@highlandsniptechnology.com wrote:> On Sun, 04 Jul 2021 14:23:41 -0700, jlarkin@highlandsniptechnology.com > wrote: > >> I'm trying to do some DC/pulse testing on a phemt, partly to validate >> a Spice model. The RF data sheets are mostly useless for time domain >> use. >> >> The danged thing keeps oscillating on a regular surfmount adapter, and >> that makes measurements weird. So I hacked this. >> >> https://www.dropbox.com/s/s8i90zlrgxdrzu2/Phemt_Dremel_1.jpg?raw=1 >> >> SOT-143 is about my resolution limit for handheld dremeling. It >> probably doesn't need the vias... the edge launch SMA connectors >> connect both sides pretty well. >> >> Our general impression is that you can drive these things really hard >> and get unexpected results, at suitably low duty cycles. We take Abs >> Max ratings as polite suggestions. > Shot with the Samsung phone. There's a selfie in there! > John, I have a soon to be dentist in the family and I got a bag of used dental bits. (Cost about $13K each) They drill just fine, but the problem I have is my Dremel has wobble. This didn't just start with dental bits. Did you have any problem with wobble, did you find better collets, do I need to buy a new Dremel, or is there a higher quality dremel style high speed drill? Thanks, Mikek -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Reply by ●July 5, 20212021-07-05
On Mon, 5 Jul 2021 18:26:51 -0500, amdx <amdx@knology.net> wrote:>On 7/4/2021 4:42 PM, jlarkin@highlandsniptechnology.com wrote: >> On Sun, 04 Jul 2021 14:23:41 -0700, jlarkin@highlandsniptechnology.com >> wrote: >> >>> I'm trying to do some DC/pulse testing on a phemt, partly to validate >>> a Spice model. The RF data sheets are mostly useless for time domain >>> use. >>> >>> The danged thing keeps oscillating on a regular surfmount adapter, and >>> that makes measurements weird. So I hacked this. >>> >>> https://www.dropbox.com/s/s8i90zlrgxdrzu2/Phemt_Dremel_1.jpg?raw=1 >>> >>> SOT-143 is about my resolution limit for handheld dremeling. It >>> probably doesn't need the vias... the edge launch SMA connectors >>> connect both sides pretty well. >>> >>> Our general impression is that you can drive these things really hard >>> and get unexpected results, at suitably low duty cycles. We take Abs >>> Max ratings as polite suggestions. >> Shot with the Samsung phone. There's a selfie in there! >> > �John, I have a soon to be dentist in the family and I got a bag of >used dental bits. > >(Cost about $13K each) They drill just fine, but the problem I have is >my Dremel has wobble. > >This didn't just start with dental bits. > > �Did you have any problem with wobble, did you find better collets, do >I need to buy a new Dremel, or is there a > >higher quality dremel style high speed drill? > > ����������������������������������������� Thanks, MikekI have a fairly ordinary variable-speed Dremel, with a chuck instead of collets. I buy dental burrs on ebay and they last a long time. Small drills will flail around if you spin them too fast, but the dental burrs are designed to run at absurd RPMs and are fine. -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Reply by ●July 5, 20212021-07-05
On 7/5/2021 6:57 PM, jlarkin@highlandsniptechnology.com wrote:> On Mon, 5 Jul 2021 18:26:51 -0500, amdx <amdx@knology.net> wrote: > >> On 7/4/2021 4:42 PM, jlarkin@highlandsniptechnology.com wrote: >>> On Sun, 04 Jul 2021 14:23:41 -0700, jlarkin@highlandsniptechnology.com >>> wrote: >>> >>>> I'm trying to do some DC/pulse testing on a phemt, partly to validate >>>> a Spice model. The RF data sheets are mostly useless for time domain >>>> use. >>>> >>>> The danged thing keeps oscillating on a regular surfmount adapter, and >>>> that makes measurements weird. So I hacked this. >>>> >>>> https://www.dropbox.com/s/s8i90zlrgxdrzu2/Phemt_Dremel_1.jpg?raw=1 >>>> >>>> SOT-143 is about my resolution limit for handheld dremeling. It >>>> probably doesn't need the vias... the edge launch SMA connectors >>>> connect both sides pretty well. >>>> >>>> Our general impression is that you can drive these things really hard >>>> and get unexpected results, at suitably low duty cycles. We take Abs >>>> Max ratings as polite suggestions. >>> Shot with the Samsung phone. There's a selfie in there! >>> >> John, I have a soon to be dentist in the family and I got a bag of >> used dental bits. >> >> (Cost about $13K each) They drill just fine, but the problem I have is >> my Dremel has wobble. >> >> This didn't just start with dental bits. >> >> Did you have any problem with wobble, did you find better collets, do >> I need to buy a new Dremel, or is there a >> >> higher quality dremel style high speed drill? >> >> Thanks, Mikek > I have a fairly ordinary variable-speed Dremel, with a chuck instead > of collets. I buy dental burrs on ebay and they last a long time. > > Small drills will flail around if you spin them too fast, but the > dental burrs are designed to run at absurd RPMs and are fine. > > >I'll look into a chuck, but collets, at least on lathes are supposed to be more accurate. I'm plenty happy with the way they cut. Thanks, Mikek -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Reply by ●July 6, 20212021-07-06
Am 06.07.21 um 01:26 schrieb amdx:> This didn't just start with dental bits. > > Did you have any problem with wobble, did you find better collets, do > I need to buy a new Dremel, or is there a > > higher quality dremel style high speed drill?Here in .de we have Proxxon that seems to be a notch better and cost slightly more. No idea if they are sold in the US. cheers, Gerhard
Reply by ●July 6, 20212021-07-06
On Tue, 6 Jul 2021 08:32:24 +0200, Gerhard Hoffmann <dk4xp@arcor.de> wrote:>Am 06.07.21 um 01:26 schrieb amdx: > >> This didn't just start with dental bits. >> >> �Did you have any problem with wobble, did you find better collets, do >> I need to buy a new Dremel, or is there a >> >> higher quality dremel style high speed drill? > >Here in .de we have Proxxon that seems to be a notch better >and cost slightly more. No idea if they are sold in the US. > >cheers, GerhardI see the Proxxon used in YT videos from Europe. Looks similar (but a bit nicer) than the very consumer-y Dremels. Foredom is the professional choice for jewelers etc. It has a separate motor and flex shaft. https://amzn.to/3jPrFV4 Not sure if there is a Euro or Japanese equivalent. You can get pre-owned Foredom tools and they are still supported by the manufacturer. -- Best regards, Spehro Pefhany
Reply by ●July 6, 20212021-07-06
On Mon, 5 Jul 2021 20:21:57 -0500, amdx <amdx@knology.net> wrote:>On 7/5/2021 6:57 PM, jlarkin@highlandsniptechnology.com wrote: >> On Mon, 5 Jul 2021 18:26:51 -0500, amdx <amdx@knology.net> wrote: >> >>> On 7/4/2021 4:42 PM, jlarkin@highlandsniptechnology.com wrote: >>>> On Sun, 04 Jul 2021 14:23:41 -0700, jlarkin@highlandsniptechnology.com >>>> wrote: >>>> >>>>> I'm trying to do some DC/pulse testing on a phemt, partly to validate >>>>> a Spice model. The RF data sheets are mostly useless for time domain >>>>> use. >>>>> >>>>> The danged thing keeps oscillating on a regular surfmount adapter, and >>>>> that makes measurements weird. So I hacked this. >>>>> >>>>> https://www.dropbox.com/s/s8i90zlrgxdrzu2/Phemt_Dremel_1.jpg?raw=1 >>>>> >>>>> SOT-143 is about my resolution limit for handheld dremeling. It >>>>> probably doesn't need the vias... the edge launch SMA connectors >>>>> connect both sides pretty well. >>>>> >>>>> Our general impression is that you can drive these things really hard >>>>> and get unexpected results, at suitably low duty cycles. We take Abs >>>>> Max ratings as polite suggestions. >>>> Shot with the Samsung phone. There's a selfie in there! >>>> >>> �John, I have a soon to be dentist in the family and I got a bag of >>> used dental bits. >>> >>> (Cost about $13K each) They drill just fine, but the problem I have is >>> my Dremel has wobble. >>> >>> This didn't just start with dental bits. >>> >>> �Did you have any problem with wobble, did you find better collets, do >>> I need to buy a new Dremel, or is there a >>> >>> higher quality dremel style high speed drill? >>> >>> ����������������������������������������� Thanks, Mikek >> I have a fairly ordinary variable-speed Dremel, with a chuck instead >> of collets. I buy dental burrs on ebay and they last a long time. >> >> Small drills will flail around if you spin them too fast, but the >> dental burrs are designed to run at absurd RPMs and are fine. >> >> >> >I'll look into a chuck, but collets, at least on lathes are supposed to >be more accurate.Maybe so, but they are a nuisance to select and install of you want to switch to a drill or something. -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Reply by ●July 6, 20212021-07-06
On Tue, 6 Jul 2021 08:32:24 +0200, Gerhard Hoffmann <dk4xp@arcor.de> wrote:>Am 06.07.21 um 01:26 schrieb amdx: > >> This didn't just start with dental bits. >> >> �Did you have any problem with wobble, did you find better collets, do >> I need to buy a new Dremel, or is there a >> >> higher quality dremel style high speed drill? > >Here in .de we have Proxxon that seems to be a notch better >and cost slightly more. No idea if they are sold in the US. > >cheers, GerhardThe resolution of cutting FR4 freehand limited by the operator hand. The low-end Dremels, 2 or 3 speed, aren't so good. Amazon has the Proxxons. Proxxon has a lot of interesting small tools. -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
Reply by ●July 6, 20212021-07-06
On 7/6/2021 9:34 AM, jlarkin@highlandsniptechnology.com wrote:> On Mon, 5 Jul 2021 20:21:57 -0500, amdx <amdx@knology.net> wrote: > >> On 7/5/2021 6:57 PM, jlarkin@highlandsniptechnology.com wrote: >>> On Mon, 5 Jul 2021 18:26:51 -0500, amdx <amdx@knology.net> wrote: >>> >>>> On 7/4/2021 4:42 PM, jlarkin@highlandsniptechnology.com wrote: >>>>> On Sun, 04 Jul 2021 14:23:41 -0700, jlarkin@highlandsniptechnology.com >>>>> wrote: >>>>> >>>>>> I'm trying to do some DC/pulse testing on a phemt, partly to validate >>>>>> a Spice model. The RF data sheets are mostly useless for time domain >>>>>> use. >>>>>> >>>>>> The danged thing keeps oscillating on a regular surfmount adapter, and >>>>>> that makes measurements weird. So I hacked this. >>>>>> >>>>>> https://www.dropbox.com/s/s8i90zlrgxdrzu2/Phemt_Dremel_1.jpg?raw=1 >>>>>> >>>>>> SOT-143 is about my resolution limit for handheld dremeling. It >>>>>> probably doesn't need the vias... the edge launch SMA connectors >>>>>> connect both sides pretty well. >>>>>> >>>>>> Our general impression is that you can drive these things really hard >>>>>> and get unexpected results, at suitably low duty cycles. We take Abs >>>>>> Max ratings as polite suggestions. >>>>> Shot with the Samsung phone. There's a selfie in there! >>>>> >>>> John, I have a soon to be dentist in the family and I got a bag of >>>> used dental bits. >>>> >>>> (Cost about $13K each) They drill just fine, but the problem I have is >>>> my Dremel has wobble. >>>> >>>> This didn't just start with dental bits. >>>> >>>> Did you have any problem with wobble, did you find better collets, do >>>> I need to buy a new Dremel, or is there a >>>> >>>> higher quality dremel style high speed drill? >>>> >>>> Thanks, Mikek >>> I have a fairly ordinary variable-speed Dremel, with a chuck instead >>> of collets. I buy dental burrs on ebay and they last a long time. >>> >>> Small drills will flail around if you spin them too fast, but the >>> dental burrs are designed to run at absurd RPMs and are fine. >>> >>> >>> >> I'll look into a chuck, but collets, at least on lathes are supposed to >> be more accurate. > > Maybe so, but they are a nuisance to select and install of you want to > switch to a drill or something. > >Yes they are for the dental bits, they have several different size shafts vs one for most of the Dremel accesories I have. Mikek -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
