From bjtatum1 at att.net  Sat Apr  5 17:57:24 2014
From: bjtatum1 at att.net (Byron Tatum)
Date: Sat, 5 Apr 2014 14:57:24 -0700 (PDT)
Subject: [HBR] HQ-160 Osc Issue
Message-ID: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>

Hello-
? I apologize for the off-topic post, but I was hoping someone here may have a suggestion for me in trying to resolve an issue with an HQ-160 receiver. Here is the issue: The receiver has a bad?"raspy" note when listening to CW, and a bad?warbly raspy?sound when copying SSB. The problem is much worse on 10 meters than on 40 meters.
?I suspected the tuning osc may be the culprit, since the problem worsens on the upper bands. So, I warmed up an R-390A and listened to the 3.49 MC xtal osc (used on two upper bands only) and it has a nice pure note. I listened? to the harmonic of the BFO (910 KC) and it has a nice pure note. Then, I listened to the tuning osc at around 31.9 MC (HQ-160 tuned to 10 meter band) and it sounds terrible in the R-390A. The tuning osc in HQ-160 is around 3.3 MC above the receive freq. When listening to the tuning osc on the R-390A it has the same raspy note that the HQ-160 does when receiving a 10 meter carrier. The tuning osc note gets much better as the HQ-160 is taken down into the lower bands. It is still objectionable on 20 meters,on 40 meters it is noticeable but not terribly irritating.
?I?have done these things so far:
?? 1. Converted power supply to solid state and?added another choke, making it a choke input with new electrolytics. Checked for ripple, is around 2.5 mV on regulated 105 VDC.
?? 2. The tube sockets are riveted in place, and soldered on one side. I resoldered all of them with a 300 watt Weller.
?? 3. I installed?0.01 uFD bypass?caps on fil terminals of RF Amp, OSC and first mixer tube sockets.
?? 4. Cleaned all bandswitch contacts carefully, retightened all mounting and grounding screws on RF tuner assembly, and cleaned tuning caps contacts.
???5. Checked resistors in affected area to insure all in tolerance.
?After just about giving up I took a second HQ-160 that is still all-original?(one that I am nearly through cleaning up) and listened to its tuning osc on 10 meters at 31.9 MC in the R-390A. Low and behold, it had the exact same raspy sound and the other HQ-160. 10 meter on-air signals sounded nearly the same too.
?? So, I am starting to think that the HQ-160 has something inheritent in its design to cause the raspy tuning osc note? I got out an HQ-170 that I did a lot of things too a couple of years back and it sounds great on 10 meter SSB. When you look at the large massive coils and tuning capacitor assembly of the HQ-160 it appears to be of much better quality than the little canned coils of HQ-170. At least, that is my first take on it.
?? Any suggestions appreciated,
????????????????? Byron WA5THJ??

From waltah at earthlink.net  Sat Apr  5 22:50:38 2014
From: waltah at earthlink.net (Walt Hutchens)
Date: Sat, 5 Apr 2014 22:50:38 -0400
Subject: [HBR] HQ-160 Osc Issue
In-Reply-To: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>
Message-ID: <887919487.20140405225038@earthlink.net>

Byron said:

> So, I am starting to think that the HQ-160 has something inheritent
> in its design to cause the raspy tuning osc note?

You're not the only one to deal with this:

http://www.antiqueradios.com/forums/viewtopic.php?f=5&t=243032

However, I think that discussion heads in the wrong direction since
most of the focus is on the second converter -- 3.3 Mcs down to 455kcs
or something like that.  By listening to the 1st oscillator in the
R390A and finding it raspy, you've proven that's the place to start
work.

Also, substituting newer 'hotter' tubes in old sets isn't a good idea.
The challenge at HF is to handle signals of tens or hundreds of
MILLIvolts without trashing the whole band: Any new tube type requires
design adjustment that will rarely be simple. The 6BA6-6BE6 combo is
perfectly adequate for a receiver of this type and vintage.

Several things come to mind:

First I would check voltages in the oscillator and mixer stages with a
DVM looking not just for a correct number but also for a twitchy value
as that suggests that you're near the problem. Then, in order:

1. Bad rotor contacts on the tuning cap.  This problem, however,
usually varies substantially as you tune and may even go away
momentarily at certain dial settings (that you can never find again!)
Fool around with a screwdriver, shorting the rotor shaft to the frame
to take evidence on this one.

Crashing noises as you tune that cannot be eliminated by cleaning the
contacts suggest skipping to #5, VHF parasitics.

2. Bad oscillator or mixer tube. MANY of the NOS tubes have itty-bitty
chunks of cathode material adrift in there. Tapping lightly with a
screwdriver on the 6BE6 and 6C4 might be interesting -- any
substantial change when listening to the note suggests trying a
replacement in that socket.

3. Bad capacitors.  Every capacitor in an oscillator or mixer circuit
can cause this symptom and it will be dramatically worse at higher
frequencies because the amount of phase shift caused by whatever is
going on inside the cap requires a much larger frequency jump on
higher bands.

This is the most likely problem; I mention it third because the
best way to troubleshoot it is to replace the caps, one-by-one.

Sometimes a DVM will show that a bad cap acts like a battery due to
electrolytic corrosion: Any cap that shows even mV after the set has
been off overnight is a good place to start with replacement.

Those black plastic-encased paper caps in the BC-348 and other wartime
sets are famous for that.  .2V on those things, no load.

Use a fiber rod to press lightly on each cap while listening to the osc.
signal.  Pressure on any cap will move the oscillator around, but
anything sudden or crunchy sounding is proof beyond reasonable doubt.

If none of the above nails a specific cap then replace all the caps in
the oscillator and mixer circuits -- bypasses too. They're all
carrying RF so they can all cause a frequency shift if unstable.

Don't worry about temperature coefficients at first: Find the problem
with any cap that will handle the voltage and is close to the right
value, then go looking for the exact right part.

4. Bad resistor.  Why sure ... the old carbon composition resistors
all die badly, and sometimes with a poor contact between the lead and
the core.   If changing caps doesn't fix it then go through all the
resistors using modern carbon film units.

Here again pressing gently on the various parts may find a bad actor.

5. VHF oscillation in the 6C4 circuit.  That tube will perk to
somewhere close to 200 Mcs in a good circuit so long leads (as in an
HF set) could cause trouble.   Touching various points in the circuit
with the lead of a wooden pencil (use HV care ...) will often identify
these sorts of bad actor circuits.

In a new design a VHF parasitic would be a pretty good bet but in a
factory set with those 22 ohm resistors in the grid and plate
circuits, not so much. But I would poke it with the pencil lead before
spending a lot of time on replacing parts.

Drift and mechanical instability in sets of this vintage on the high
bands (compared to an R-390A or modern set) is probably built in. But
a note such that SSB cannot be understood and CW is raspy -- no.
That's a findable problem.

Walt
KJ4KV

Walt Hutchens


From whitebear1122 at comcast.net  Sun Apr  6 17:35:58 2014
From: whitebear1122 at comcast.net (Whitebear1122)
Date: Sun, 6 Apr 2014 16:35:58 -0500
Subject: [HBR] HBR-13 Progress
In-Reply-To: <887919487.20140405225038@earthlink.net>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>
	<887919487.20140405225038@earthlink.net>
Message-ID: <863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net>

Thought I'd stop by and mention that I'm still making progress on the HBR-13 receiver, albeit slow progress.  I finished drilling the BFO cabinet over the weekend.  I have all the holes drilled and punched and the box mounted to the chassis.  I tend to overanalyze things to it took forever to make sure the BFO tune cap was lined up with the front panel bushing.  I'm a firm believer of "measure 100 times, cut 2 or 3 times"  hi hi 

I've come to the conclusion that I hate using a hand drill for anything on the HBR.  I drilled most of the holes with the drill press at work and they are all positioned fine.  The hand drilled holes are always off.  I might start looking around for a used drill press and keep it in the garage.  The milling machine at work has been a godsend and I"ve been able to learn how to use it and do all the chassis and front panel milling.  

A couple weeks back I brought a question to this list about the oddball screw size for the Eddystone 3 section variable capacitor.  Thanks again for the responses that solved the problem.  Walt Hutchins sent me 4 of those screws so I was good to go.  Last week I cut and built up a small stack of 1/8" aluminum bar to support the 3 section variable rather than standing it off the chassis on the two end screws.  This was done at Brecks recommendation.  The variable capacitor is well supported now and rock stable.  Yesterday I attached it to the RF sub chassis and it all fits and the variable shaft lines up with the Eddystone dial.  

Today I would like to line up and attach the rf sub chassis to the main chassis.  The only mechanicals left are main on the rear chassis where I have to drill holes for the AC power cord, fuse, and Cinch Jones terminal block for antenna, speaker, and mute. 

So I may be able to start wiring in another week or so.

I am curious (or apprehensive) to find out this radio performs after it's built.  I followed Ted Crosby's HBR-13 design with the exception of the IF transformers.  For the 1610 KC IF transformers I'm using two 1410 KC transformers from a BC-454 junker unit.  The plan is to change out the internal fixed capacitor and raise it to 1610.  I also acquired a set of 1650 KC IF transformers from a junker Hallicrafters SX-100 and have them in standby mode incase the 454's don't work out.  For the 100 KC IF's, I'm using 4 85 KC transformers from junker BC-453.  

I currently have a plexiglass front panel attached to the chassis and the Eddystone slide rule dial mounted.  It is intriguing to be able to look into the radio through the front panel and see some of the guts.  I haven't figured out what knobs to use.  I have some Daka knobs like the ones Ted Crosby used on his HBR but I'm not so sure they look that great on the 13.  

Anyone else building an HBR at the moment?

My long term plan for the past 40 years has been to build my own receiver, transmitter, vfo, and amplifier.   It's always been the mechanicals that held me back but I seem to have figured that out now.  IF the HBR-13 works then I'm moving on and building a transmitter.  

73, Scott WA9WFA

From mmarris at notecraft.com  Sun Apr  6 17:46:55 2014
From: mmarris at notecraft.com (Martin Marris)
Date: Sun, 6 Apr 2014 17:46:55 -0400
Subject: [HBR] HBR-13 Progress
In-Reply-To: <863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>	<887919487.20140405225038@earthlink.net>
	<863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net>
Message-ID: <001501cf51e1$bafb8150$30f283f0$@notecraft.com>

>> might start looking around for a used drill press and keep it in the
garage.<<

I agonized over that one for months. A good used drill press is still fairly
pricey. In the end I bought a Chinese-made Harbor Freight floor-standing
drill press for about $300 and I'm very pleased with it. I replaced the
stock chuck with a high-end Jacobs chuck that will accept the smallest drill
bits (that was another $100).

IMO, unless you're going to be using a drill press a lot, the HB model is
fine.

Good luck with your complete homebrewed station! I am working on a similar
all-tube station project, but with lower-end circuits -- more like a "Novice
station on steroids."

Martin, KB1WSY



From mmarris at notecraft.com  Sun Apr  6 17:49:52 2014
From: mmarris at notecraft.com (Martin Marris)
Date: Sun, 6 Apr 2014 17:49:52 -0400
Subject: [HBR] HBR-13 Progress
In-Reply-To: <001501cf51e1$bafb8150$30f283f0$@notecraft.com>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>	<887919487.20140405225038@earthlink.net>	<863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net>
	<001501cf51e1$bafb8150$30f283f0$@notecraft.com>
Message-ID: <001601cf51e2$248ccde0$6da669a0$@notecraft.com>

Sorry, typo, I meant that the "HF" (Harbor Freight) new drill press is fine.

-----Original Message-----
From: hbr-bounces at mailman.qth.net [mailto:hbr-bounces at mailman.qth.net] On
Behalf Of Martin Marris
Sent: Sunday, April 06, 2014 17:47
To: 'HBR Receiver List'
Subject: Re: [HBR] HBR-13 Progress

>> might start looking around for a used drill press and keep it in the
garage.<<

I agonized over that one for months. A good used drill press is still fairly
pricey. In the end I bought a Chinese-made Harbor Freight floor-standing
drill press for about $300 and I'm very pleased with it. I replaced the
stock chuck with a high-end Jacobs chuck that will accept the smallest drill
bits (that was another $100).

IMO, unless you're going to be using a drill press a lot, the HB model is
fine.

Good luck with your complete homebrewed station! I am working on a similar
all-tube station project, but with lower-end circuits -- more like a "Novice
station on steroids."

Martin, KB1WSY


______________________________________________________________
HBR mailing list
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Please help support this email list: http://www.qsl.net/donate.html



From waltah at earthlink.net  Sun Apr  6 19:52:22 2014
From: waltah at earthlink.net (Walt Hutchens)
Date: Sun, 6 Apr 2014 19:52:22 -0400
Subject: [HBR] HBR-13 Progress
In-Reply-To: <001601cf51e2$248ccde0$6da669a0$@notecraft.com>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>
	<887919487.20140405225038@earthlink.net>
	<863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net>
	<001501cf51e1$bafb8150$30f283f0$@notecraft.com>
	<001601cf51e2$248ccde0$6da669a0$@notecraft.com>
Message-ID: <1803960564.20140406195222@earthlink.net>

Martin said:

> I meant that the "HF" (Harbor Freight) new drill press is fine.

They have a small (tabletop) model that goes for under $100 and works
fine for many jobs. I bought mine at a fleamarket maybe 20 years ago.  

However I find I can do more accurate work with a hand drill in most
cases.  It's all about control and when I'm cranking that thing I can
stop instantly if something is going off.

The key is accurate layout, centerpunching, and supporting the work
area so the drill doesn't walk downhill due to the chassis bending.
AND sharp drills ...

It might be a bit slower but when considering the higher frequency of
exactly right, the difference is small.

Walt
KJ4KV


From whitebear1122 at comcast.net  Sun Apr  6 20:03:13 2014
From: whitebear1122 at comcast.net (Whitebear1122)
Date: Sun, 6 Apr 2014 19:03:13 -0500
Subject: [HBR] HBR-13 Progress
In-Reply-To: <1803960564.20140406195222@earthlink.net>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>
	<887919487.20140405225038@earthlink.net>
	<863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net>
	<001501cf51e1$bafb8150$30f283f0$@notecraft.com>
	<001601cf51e2$248ccde0$6da669a0$@notecraft.com>
	<1803960564.20140406195222@earthlink.net>
Message-ID: <58795DC1-BFE0-4D36-AEA6-8FD67A6C22D1@comcast.net>

When using the hand drill on the chassis I use a center punch and put a divit into the aluminum and then come in with the drill at slow speeds.  The larger the drill bit size the greater error I have.  You bring up a good point on the sharp bits though.  I'm using my ancient bits which are likely contributing to the problem.  I'll buy some new bits this week.

On my 17" x 12"x 3" chassis I put a piece of 4"x4" cedar inside the chassis to drill against, then I use some Quick Grips to hold the chassis to the bench.  Center the drill bit on the divit and drill.  

Are you able to get accurate location for large bits like 3/8" or 1/2"?  The small ones are good but I seem to get more error with the larger ones.  

73, Scott WA9WFA
On Apr 6, 2014, at 6:52 PM, Walt Hutchens <waltah at earthlink.net> wrote:



From waltah at earthlink.net  Sun Apr  6 20:55:36 2014
From: waltah at earthlink.net (Walt Hutchens)
Date: Sun, 6 Apr 2014 20:55:36 -0400
Subject: [HBR] HBR-13 Progress
In-Reply-To: <58795DC1-BFE0-4D36-AEA6-8FD67A6C22D1@comcast.net>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>
	<887919487.20140405225038@earthlink.net>
	<863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net>
	<001501cf51e1$bafb8150$30f283f0$@notecraft.com>
	<001601cf51e2$248ccde0$6da669a0$@notecraft.com>
	<1803960564.20140406195222@earthlink.net>
	<58795DC1-BFE0-4D36-AEA6-8FD67A6C22D1@comcast.net>
Message-ID: <6560834.20140406205536@earthlink.net>

Whitebear1122 said:

> Are you able to get accurate location for large bits like 3/8" or
> 1/2"?  The small ones are good but I seem to get more error with the larger ones.

With the big ones on a soft aluminum chassis results aren't going to
be very good.  Depending on the precision that's needed I may use a
reamer or a file to enlarge a 5/16" hole.  At 1/2" and up I have
socket punches for most sizes and I drill a bit oversize for the punch
screw and center it using the marks that are (usually) on the sides of
the punch.

Walt
KJ4KV


From bear57 at telus.net  Sun Apr  6 21:20:24 2014
From: bear57 at telus.net (Lorne Barber)
Date: Sun, 6 Apr 2014 18:20:24 -0700
Subject: [HBR] HBR-13 Progress
In-Reply-To: <58795DC1-BFE0-4D36-AEA6-8FD67A6C22D1@comcast.net>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com>	<887919487.20140405225038@earthlink.net>	<863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net>	<001501cf51e1$bafb8150$30f283f0$@notecraft.com>	<001601cf51e2$248ccde0$6da669a0$@notecraft.com>	<1803960564.20140406195222@earthlink.net>
	<58795DC1-BFE0-4D36-AEA6-8FD67A6C22D1@comcast.net>
Message-ID: <007b01cf51ff$8debe0b0$a9c3a210$@net>

Hi Scott, I have had decent success starting off with a small bit and
working my way up to the size required, after center punching of course.
A good point on sharp bits, I am as guilty as anyone trying to get "one
more" hole from a dull bit.
Good luck es 73.
Lorne
VE7BOX

-----Original Message-----
From: hbr-bounces at mailman.qth.net [mailto:hbr-bounces at mailman.qth.net] On
Behalf Of Whitebear1122
Sent: April-06-14 5:03 PM
To: HBR Receiver List
Subject: Re: [HBR] HBR-13 Progress

When using the hand drill on the chassis I use a center punch and put a
divit into the aluminum and then come in with the drill at slow speeds.  The
larger the drill bit size the greater error I have.  You bring up a good
point on the sharp bits though.  I'm using my ancient bits which are likely
contributing to the problem.  I'll buy some new bits this week.

On my 17" x 12"x 3" chassis I put a piece of 4"x4" cedar inside the chassis
to drill against, then I use some Quick Grips to hold the chassis to the
bench.  Center the drill bit on the divit and drill.  

Are you able to get accurate location for large bits like 3/8" or 1/2"?  The
small ones are good but I seem to get more error with the larger ones.  

73, Scott WA9WFA
On Apr 6, 2014, at 6:52 PM, Walt Hutchens <waltah at earthlink.net> wrote:


______________________________________________________________
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From aaf-radio-1 at aafradio.org  Sun Apr  6 21:41:40 2014
From: aaf-radio-1 at aafradio.org (Mike Hanz)
Date: Sun, 06 Apr 2014 21:41:40 -0400
Subject: [HBR] HBR-13 Progress
In-Reply-To: <6560834.20140406205536@earthlink.net>
References: <1396735044.48698.YahooMailNeo@web181506.mail.ne1.yahoo.com><887919487.20140405225038@earthlink.net><863E272A-E22C-4F32-BBAC-891314DD3462@comcast.net><001501cf51e1$bafb8150$30f283f0$@notecraft.com><001601cf51e2$248ccde0$6da669a0$@notecraft.com><1803960564.20140406195222@earthlink.net><58795DC1-BFE0-4D36-AEA6-8FD67A6C22D1@comcast.net>
	<6560834.20140406205536@earthlink.net>
Message-ID: <53420254.2060603@aafradio.org>

But by *far* the most accurate method is to use a step drill, starting 
with a #0 or #1 center drill.  I use center drills often with a hand 
drill to start quick jobs too easy to put on the milling machine - it 
will provide a consistent center, even when all you have is two 
orthogonal scratch marks on the workpiece.  No center punch 
required...and in fact the punch can move the center a noticeable 
amount, so I almost never use one.  Irwin makes the best step drills, 
but there are Chinese copies that will get you through a few projects 
before they get too dull and require a cutting edge touchup with a 
grinding wheel.  Use kerosene or WD-40 as a cutting edge coolant in 
aluminum, especially in the soft 5052-H32 alloy favored for chassis 
material - it's gummy and needs a coolant even more than harder alloys.

            73,
  - Mike  KC4TOS
  www.aafradio.org

On 4/6/2014 8:55 PM, Walt Hutchens wrote:
> Whitebear1122 said:
>> Are you able to get accurate location for large bits like 3/8" or
>> 1/2"?  The small ones are good but I seem to get more error with the larger ones.
> With the big ones on a soft aluminum chassis results aren't going to
> be very good.  Depending on the precision that's needed I may use a
> reamer or a file to enlarge a 5/16" hole.  At 1/2" and up I have
> socket punches for most sizes and I drill a bit oversize for the punch
> screw and center it using the marks that are (usually) on the sides of
> the punch.


From Ejparagi at aol.com  Mon Apr  7 08:21:52 2014
From: Ejparagi at aol.com (Ejparagi at aol.com)
Date: Mon, 7 Apr 2014 08:21:52 -0400 (EDT)
Subject: [HBR] HBR-13 Progress
Message-ID: <9d57.521422a.4073f260@aol.com>

Hi Scott,
 
Another suggestion for holes in the 1/4 to 1/2 inch range is the use of  
brad point drills (sometimes referred to as "spur" drills), commonly used on  
wood and sheet metal.  They are also referred to as "sheet metal  drills."  
Harbor Freight and Sears have sets of these that go to  a half inch in 
diameter.  They have a very sharp point that is easily  centered on even shallow 
prick punch marks (steeper angle than a center  punch).  I have used them in 
both hand held drills and drill presses with  good results.  You might want 
to buy only two or three sizes that would  receive the most use from a 
local hardware store if you have a well stocked one  nearby.
 
Working up to a hole with successively larger conventional drills also  
works well as someone already mentioned.  You could buy a couple of  good 1/16 
inch or 3/32 inch drills for accurately locating the intended hole and  then 
use your existing larger bits to work up to the desired diameter.  Use  a 
center punch to start conventional drill bits.  I used this method for  
years, sometimes augmented by a taper reamer until I could afford step drills  
and spur drills.  By the way, I added to my tool collection over the years  by 
asking for specific tools for birthday and Christmas gifts.  Make a list  
and add to it when you think of tools that would be of use to you so you are  
prepared when someone asks for gift suggestions.
 
Sounds like you are making good progress, and that is what it's all  about.
 
73 es GL,
Ed
WB9RMA
 
 
 
 
In a message dated 4/6/2014 8:03:21 P.M. Eastern Daylight Time,  
whitebear1122 at comcast.net writes:

When  using the hand drill on the chassis I use a center punch and put a 
divit into  the aluminum and then come in with the drill at slow speeds.  The 
larger  the drill bit size the greater error I have.  You bring up a good 
point  on the sharp bits though.  I'm using my ancient bits which are likely  
contributing to the problem.  I'll buy some new bits this week.

On  my 17" x 12"x 3" chassis I put a piece of 4"x4" cedar inside the 
chassis to  drill against, then I use some Quick Grips to hold the chassis to the  
bench.  Center the drill bit on the divit and drill.  

Are  you able to get accurate location for large bits like 3/8" or 1/2"?  
The  small ones are good but I seem to get more error with the larger ones.   

73, Scott WA9WFA
On Apr 6, 2014, at 6:52 PM, Walt Hutchens  <waltah at earthlink.net>  wrote:


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From tshoppa at wmata.com  Mon Apr  7 08:29:08 2014
From: tshoppa at wmata.com (Shoppa, Tim)
Date: Mon, 7 Apr 2014 12:29:08 +0000
Subject: [HBR] HBR-13 Progress
In-Reply-To: <9d57.521422a.4073f260@aol.com>
References: <9d57.521422a.4073f260@aol.com>
Message-ID: <303A17BD5F8FA34DA45EEC245271AC0B94A3B5A4@JGEX2K10MBX2.wmata.local>

For anything bigger than 1/8 but less than 3/4 inch in sheet metal,  I start with a 1/8 hole then I use a "step drill". E.g.  http://www.mcmaster.com/#step-drills/=rfkfol

Home Depot also sells step drills. The Unibit brand is pretty good.

Harbor Freight also sells step drills. I bought some once when I lent out my real Unibit. They harbor freight stuff will work but they just feel like crap.

I have a mix of Greenlee (inch) and Mouser (Metric) punches for sizes bigger than 3/4 inch (e.g. tube sockets) in aluminum and plastic.

Tim.

-----Original Message-----
From: hbr-bounces at mailman.qth.net [mailto:hbr-bounces at mailman.qth.net] On Behalf Of Ejparagi at aol.com
Sent: Monday, April 07, 2014 8:22 AM
To: hbr at mailman.qth.net
Subject: Re: [HBR] HBR-13 Progress

Hi Scott,
 
Another suggestion for holes in the 1/4 to 1/2 inch range is the use of brad point drills (sometimes referred to as "spur" drills), commonly used on wood and sheet metal.  They are also referred to as "sheet metal  drills."  
Harbor Freight and Sears have sets of these that go to  a half inch in diameter.  They have a very sharp point that is easily  centered on even shallow prick punch marks (steeper angle than a center  punch).  I have used them in both hand held drills and drill presses with  good results.  You might want to buy only two or three sizes that would  receive the most use from a local hardware store if you have a well stocked one  nearby.
 
Working up to a hole with successively larger conventional drills also works well as someone already mentioned.  You could buy a couple of  good 1/16 inch or 3/32 inch drills for accurately locating the intended hole and  then use your existing larger bits to work up to the desired diameter.  Use  a center punch to start conventional drill bits.  I used this method for years, sometimes augmented by a taper reamer until I could afford step drills and spur drills.  By the way, I added to my tool collection over the years  by asking for specific tools for birthday and Christmas gifts.  Make a list and add to it when you think of tools that would be of use to you so you are prepared when someone asks for gift suggestions.
 
Sounds like you are making good progress, and that is what it's all  about.
 
73 es GL,
Ed
WB9RMA
 
 
 
 
In a message dated 4/6/2014 8:03:21 P.M. Eastern Daylight Time, whitebear1122 at comcast.net writes:

When  using the hand drill on the chassis I use a center punch and put a divit into  the aluminum and then come in with the drill at slow speeds.  The larger  the drill bit size the greater error I have.  You bring up a good point  on the sharp bits though.  I'm using my ancient bits which are likely contributing to the problem.  I'll buy some new bits this week.

On  my 17" x 12"x 3" chassis I put a piece of 4"x4" cedar inside the chassis to  drill against, then I use some Quick Grips to hold the chassis to the bench.  Center the drill bit on the divit and drill.  

Are  you able to get accurate location for large bits like 3/8" or 1/2"?  
The  small ones are good but I seem to get more error with the larger ones.   

73, Scott WA9WFA
On Apr 6, 2014, at 6:52 PM, Walt Hutchens  <waltah at earthlink.net>  wrote:


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From aaf-radio-1 at aafradio.org  Mon Apr  7 09:11:54 2014
From: aaf-radio-1 at aafradio.org (Mike Hanz)
Date: Mon, 07 Apr 2014 09:11:54 -0400
Subject: [HBR] HBR-13 Progress
In-Reply-To: <303A17BD5F8FA34DA45EEC245271AC0B94A3B5A4@JGEX2K10MBX2.wmata.local>
References: <9d57.521422a.4073f260@aol.com>
	<303A17BD5F8FA34DA45EEC245271AC0B94A3B5A4@JGEX2K10MBX2.wmata.local>
Message-ID: <5342A41A.8000501@aafradio.org>

Seems to be a delayed echo on this list. :-) Anyway, the step drills go 
up to 1.375" in hole diameter, and as I mentioned yesterday in 
recommending them, are accurate in hitting the desired finish location.  
It also provides a perfectly circular hole, and with a deft hand, 
deburrs the top edge when you're finished.

It is absolutely mandatory to clamp your workpiece on the drill press 
and use an appropriate speed limit as you increase the size - there are 
speed and feed rate tables for machining online, like this one: 
http://www.americanmachinetools.com/images/lathe_table_6.jpg Otherwise 
you risk burning the cutting edge with too high a speed and that's not a 
good thing.

           73,
  - Mike  KC4TOS
www.aafradio.org

On 4/7/2014 8:29 AM, Shoppa, Tim wrote:
> For anything bigger than 1/8 but less than 3/4 inch in sheet metal,  I start with a 1/8 hole then I use a "step drill". E.g.  http://www.mcmaster.com/#step-drills/=rfkfol
> Home Depot also sells step drills. The Unibit brand is pretty good.
> Harbor Freight also sells step drills. I bought some once when I lent out my real Unibit. They harbor freight stuff will work but they just feel like crap.
> I have a mix of Greenlee (inch) and Mouser (Metric) punches for sizes bigger than 3/4 inch (e.g. tube sockets) in aluminum and plastic.


From brianburns1066 at gmail.com  Sun Apr 20 13:28:13 2014
From: brianburns1066 at gmail.com (Brian Burns)
Date: Sun, 20 Apr 2014 10:28:13 -0700
Subject: [HBR] The I.F transformer problem
Message-ID: <CAMNk5SoRqwx0NyLmOF61YBKWfvEaAu3x3SR5MafCkaPODYGnpw@mail.gmail.com>

Hello All,

I'm new to the HBR list, but have long been interested in ham receiver
design and construction. As K6UCD in 1955 I built one of Byron Goodman's
band imaging receivers for 80 and 40 meters. It was the double conversion
design with a 1700 kc first IF. In that era it was no problem to order up a
Millen transformer for that frequency, though it took an agonizing six
weeks for it to be delivered!

So, having been re-enthused with ham radio after all these years, against
my better judgement, I thought I would like to build another receiver.

I have spent quite a bit of time looking at old handbooks, back issues of
QST, and arguing with fans of regens about the practicality of those old
timers for ham use. I've wanted to see what has risen to the top as some of
the better designs from the tube era. The problem of course is that all of
the superhets specify IF transformers, and//or coils from J.W. Miller,
Millen, etc.

Max Robinson of the funwithtubes list suggested a work-around taken from
one of the NC-300 models, for a capacitively coupled pair of torodial
coils; see attached schematic in .pdf. I'm not sure if this list permits
attachments. If not, I can email you a copy.

So, if there are currently sources for IF transformers, or if anyone has
used Max's scheme, I would really appreciate hearing about it.

Cheers,

Brian Burns   Ex: W5BRO, K6UCD

From brianburns1066 at gmail.com  Mon Apr 21 11:51:08 2014
From: brianburns1066 at gmail.com (Brian Burns)
Date: Mon, 21 Apr 2014 08:51:08 -0700
Subject: [HBR] Max's schematic
Message-ID: <CAMNk5SrkBQzjxvEC7_MU8gm8y4DRgx4zY2tc0LfUyeOxX0Sutw@mail.gmail.com>

Hello All,



Apparently my attachment of Max Robinson?s schematic exceeded the list?s
allowable size for postings. So, if you would like a .pdf copy of his I.F.
?filter? circuit, just email me off list at:



brian at lessonsinlutherie.com



Cheers,



Brian Burns

