• To anyone looking to acquire commercial radio programming software:

    Please do not make requests for copies of radio programming software which is sold (or was sold) by the manufacturer for any monetary value. All requests will be deleted and a forum infraction issued. Making a request such as this is attempting to engage in software piracy and this forum cannot be involved or associated with this activity. The same goes for any private transaction via Private Message. Even if you attempt to engage in this activity in PM's we will still enforce the forum rules. Your PM's are not private and the administration has the right to read them if there's a hint to criminal activity.

    If you are having trouble legally obtaining software please state so. We do not want any hurt feelings when your vague post is mistaken for a free request. It is YOUR responsibility to properly word your request.

    To obtain Motorola software see the Sticky in the Motorola forum.

    The various other vendors often permit their dealers to sell the software online (i.e., Kenwood). Please use Google or some other search engine to find a dealer that sells the software. Typically each series or individual radio requires its own software package. Often the Kenwood software is less than $100 so don't be a cheapskate; just purchase it.

    For M/A Com/Harris/GE, etc: there are two software packages that program all current and past radios. One package is for conventional programming and the other for trunked programming. The trunked package is in upwards of $2,500. The conventional package is more reasonable though is still several hundred dollars. The benefit is you do not need multiple versions for each radio (unlike Motorola).

    This is a large and very visible forum. We cannot jeopardize the ability to provide the RadioReference services by allowing this activity to occur. Please respect this.

Drilling for NMOil - to Punch or to Drill?

Status
Not open for further replies.

RadioDaze

Member
Joined
Oct 5, 2006
Messages
2,034
Location
Orange County, California, USA
I've read posts that suggest using a 3/4" steel punch gives a cleaner hole than a hole saw for an NMO mount. Would someone please identify a source for a good, properly-sized punch?

Feel free to go off-topic and tell me why a different method is just as good. Maybe all I need is a potato, sewing needle, ice cube and alcohol.
 

FFPM571

Member
Premium Subscriber
Joined
Mar 11, 2003
Messages
1,706
Location
Nashvillle
If antenna manufacturers wanted you to use a hole punch they would sell them. Antenna manufacturers sell antenna hole saws that are designed to the the exact size you need.
 

SteveC0625

Order of the Golden Dino since 1972
Premium Subscriber
Joined
Oct 24, 2009
Messages
2,795
Location
Northville, NY (Fulton County)
I've read posts that suggest using a 3/4" steel punch gives a cleaner hole than a hole saw for an NMO mount. Would someone please identify a source for a good, properly-sized punch?

Feel free to go off-topic and tell me why a different method is just as good. Maybe all I need is a potato, sewing needle, ice cube and alcohol.
It is called a "chassis punch" and was very commonly used back when electronic folk built their own gear on aluminum or steel boxes. They're available from any good tool supplier, and you can usually find a bargain on one on Ebay without too much searching. Greenlee was a well known manufacturer.

There's lots of debate about using a chassis punch versus one of the better hole saws marketed specifically for this task. I don't think there is a single right way for this and I have both in my toolkit.

One downside to using a chassis punch is that you have to be able to reach the underside of the hole to assemble the punch prior to use. That usually means dropping the headliner enough to reach in there to place the bottom half of the punch. That can be a major task given today's vehicles with air bags all over the place. Many installers have learned how to use a hole saw to maximum advantage in this situation. It's generally faster and less labor intensive.
 

cmdrwill

Member
Joined
Mar 30, 2005
Messages
3,984
Location
So Cali
Correct, chassis punch. Greenlee is one manufacturer. And I DO some times use the chassis punch.
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
23,617
Location
Hiding in a coffee shop.
If it makes a clean 3/4 inch hole it'll be just fine, doesn't matter if it's a hole saw or a chassis punch. Never understood why some are so against punches. I think some just don't know what they are and it frightens them.

A new chassis punch will likely cost more than a new hole saw.
Hole saws are great when you can't get to both side, as said above.
Chassis punches make really clean holes. It's a slower process, so might be a good choice where you have to be really careful about paint jobs.

Important thing to note is that you need to be 100% sure you are getting a 3/4" diameter chassis punch and NOT a 3/4 "Trade size" punch. The "Trade Size" punches are designed for 3/4" electrical conduit fittings and are not 3/4" diameter. A 1/2" trade size punch is 7/8" and while it might seem "close enough", it isn't.

Sources, McMaster/Carr, Grainger, a really good hardware store (not Home Depot/Lowe's unless they are specially ordering)

I noticed when I was at the local hardware store last weekend that DeWalt was selling hole saws specifically designed for metal drilling. 3/4" was about $12.00. The "real" Larsen/Anetennex/Laird, etc hole saws are bit more expensive.

Be careful with "cone" bits or "Christmas Tree" bits as if you are not careful they'll tear up the metal. They also require a lot of clearance on the underside.
 

Project25_MASTR

Millennial Graying OBT Guy
Joined
Jun 16, 2013
Messages
4,164
Location
Texas
As stated. There are really 3 different methods.

Step bit (aka Unibit): If you do a lot of drilling into 1/4" or less metal...you really need to own one of these (they eat steel for breakfast). If you get them too hot they'll burn and stop cutting. Gotta be careful when drilling roofs with them (I'd actually recommend drilling up and not down) and check every step to ensure you don't overdrill. ~$40

Hole Punch (GreenLee Knock Out): Works. As stated it requires access to the underside of the vehicle's roof. Also requires a pilot hole to be drilled (so you still have to drill the roof). Quite pricey though.I don't remember what size hole the pilot is but I want to say it's 3/8" (which could come in handy as there are quite a few 3/8" antenna mounts as well). Also has the longest lasting life. Personally I think this would be the better solution for aluminum bodied vehicles. ~$50

NMO Hole Saw: Think I know of two brands (one is Laird which is what I own). This is designed to be used from the top of the vehicle. The NMO mount covers all areas of paint which this rubs away. Saw blades are replaceable but like any hole saw...you worry about the cut quality going into it. ~$35

Here's a gif for option 3 (on my POV).
NMO_zpsk2zel4ea.gif
 

W5SAB

Member
Joined
Feb 5, 2016
Messages
21
I'd go with a cheap step bit through Amazon or ebay. It's quick, does clean edges, and will let you get the minimum size hole you need

Sent from my XT1585 using Tapatalk
 

N4GIX

Member
Premium Subscriber
Joined
May 27, 2015
Messages
2,124
Location
Hot Springs, AR
While rummaging through my Jensen Toolkit looking for my crimper, I found my NMO Hole Saw. I long ago lost count of how many holes I've cut with it over the time I owned the GE Service Station in Kingsville, TX.
 

RadioDaze

Member
Joined
Oct 5, 2006
Messages
2,034
Location
Orange County, California, USA
I have used a step bit on small aluminum project enclosures, with a drill press. But I'd feel safer with a dedicated hole saw with a nice, sharp virgin blade from an antenna company, even at the higher price.

Mostly, I'd feel safest with it being done by a pro shop, if I can find one around here.
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
23,617
Location
Hiding in a coffee shop.
Mostly, I'd feel safest with it being done by a pro shop, if I can find one around here.

You should not have an issue finding a radio shop in your area that can do this for you. While it's not hard to do on your own, a shop will have all the right tools and experience to do it right. They'll be able to properly crimp the connector on the end. While you are there, have them put your antenna on an analyzer and make sure it's tuned correctly. It'll cost you more in the short term, but getting it all set up correctly comes with a good piece of mind.
 

eng5

Member
Premium Subscriber
Joined
Aug 31, 2005
Messages
66
If you go with the punch, make sure you're using one that makes a 3/4" hole, not one that makes a hole for a 3/4" conduit. They're different.
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
I use the Antenex bit that is made specially for a NMO 3/4 hole. As another member noted it strips some of the paint away so there is better contact of the ground portion of the mount. It does a great job of drilling the holes. One of the local two-way radio shops use them so I figured they were the best to use.
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
23,617
Location
Hiding in a coffee shop.
I use the Antenex bit that is made specially for a NMO 3/4 hole. As another member noted it strips some of the paint away so there is better contact of the ground portion of the mount. It does a great job of drilling the holes. One of the local two-way radio shops use them so I figured they were the best to use.

The NMO mounts ground from underneath, not the top. I've got an Antenex hole saw and it does nothing to the paint side of the hole. That should't be stripped back as it needs a nice clean place for the o-ring to seal. If your's is peeling the paint off when you use it I suspect there is something wrong with it.
 

cmdrwill

Member
Joined
Mar 30, 2005
Messages
3,984
Location
So Cali
Orange County, that is south of me and over the hill. If you want to go up to San Gabriel Valley I still do the antenna mounts. Drill or punch, I have both.
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
The NMO mounts ground from underneath, not the top. I've got an Antenex hole saw and it does nothing to the paint side of the hole. That should't be stripped back as it needs a nice clean place for the o-ring to seal. If your's is peeling the paint off when you use it I suspect there is something wrong with it.

From what I have seen it does score a tad bit top paint away. The brass ring on the NMO connector will make better contact and there's an o-ring seal there to prevent corrosion. My trunk is painted on the underside so there would not be any ground contact fron the NMO's mount.
 

Project25_MASTR

Millennial Graying OBT Guy
Joined
Jun 16, 2013
Messages
4,164
Location
Texas
From what I have seen it does score a tad bit top paint away. The brass ring on the NMO connector will make better contact and there's an o-ring seal there to prevent corrosion. My trunk is painted on the underside so there would not be any ground contact fron the NMO's mount.


The underside of the mount has teeth. As you tighten…the teeth bite and ground. All of my mounts ground and I've never bothered to strip paint from the underside.


Sent from my iPhone using Tapatalk
 

jim202

Member
Joined
Mar 7, 2002
Messages
2,729
Location
New Orleans region
The underside of the mount has teeth. As you tighten…the teeth bite and ground. All of my mounts ground and I've never bothered to strip paint from the underside.


Sent from my iPhone using Tapatalk

This question has gone on for years. There is no better right or wrong answer. But i will say that the antenna hole saw was developed for 2 reasons. One is speed on install and the second is to that the head liner is not damaged during the install.

I have run a radio shop for a number of years and time is money. If you have to drop the head liner in some of these vehicles, it takes a while to do it. Plus you stand the chance to break or damage some of the plastic hardware that holds up the head liner. I normally open up the area above one of the rear doors to take a look to see just where the rib supports are. I use a flashlight and generally have to poke a piece of wood in to hold the small space open just enough to look in there. Normally it's just the rubber seal that you can pull away from the top of the door opening.

Using a chassis punch, you have to drill a hole large enough to get the threaded bolt through. It's real easy to slip and have the drill go in too far and tear up the head liner. Then you have to have enough opening to be able to get your arm in there to reach in enough to get to the hole you drilled. If you can reach that far, you hold the smaller section of the punch and it takes a second person to twist the bolt on the top half of the punch. So now your required to pay for two people to do the job that one install tech can do himself.

Once the bottom half of the punch is on, you can tighten it up and punch the hole. Depending on just how sharp the punch is, you may or may not have a clean hole. Chances are there is a slight upward flare on the edge of the hole going to the top of the vehicle. This may or may not seal tightly depending on how much of a flare you end up with.

So do as you please. Those that vote for the punch must have all the time in the world and someone to help them. Plus they don't care about the effort and time it takes to drop the head liner enough to reach the punch location. Then have to put it all back up with no damage.
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
23,617
Location
Hiding in a coffee shop.
So do as you please. Those that vote for the punch must have all the time in the world and someone to help them. Plus they don't care about the effort and time it takes to drop the head liner enough to reach the punch location. Then have to put it all back up with no damage.

Not every antenna is mounted in the center of the roof. I've done installs where some will be easily reachable by one person. I've done some where I was mounting to a bracket, existing hardware, etc.
The hole saw is certainly my preferred tool, however there are some instances where the punch can work just as well if not better.

Most recently I was fabricating a bunch of mounts to go on a UTV roll bar. These were custom mounts that attached to an existing roll bar to hold an NMO mount. Due to the size of the bracket, it was easier to do a punch.

The OP's question was "Feel free to go off-topic and tell me why a different method is just as good. Maybe all I need is a potato, sewing needle, ice cube and alcohol."
It wasn't an argument about who should be using what tool, only looking at the pro's and con's of both.
 

Project25_MASTR

Millennial Graying OBT Guy
Joined
Jun 16, 2013
Messages
4,164
Location
Texas
Not every antenna is mounted in the center of the roof. I've done installs where some will be easily reachable by one person. I've done some where I was mounting to a bracket, existing hardware, etc.
The hole saw is certainly my preferred tool, however there are some instances where the punch can work just as well if not better.

Most recently I was fabricating a bunch of mounts to go on a UTV roll bar. These were custom mounts that attached to an existing roll bar to hold an NMO mount. Due to the size of the bracket, it was easier to do a punch.

The OP's question was "Feel free to go off-topic and tell me why a different method is just as good. Maybe all I need is a potato, sewing needle, ice cube and alcohol."
It wasn't an argument about who should be using what tool, only looking at the pro's and con's of both.

I would have to agree. When fabricating brackets it can be much easier to use a punch. When using existing holes (whether it be from a previous 3/8" or 1/2" cellular antenna install) or whatever, it is often easier to use a punch as your pilot hole for your NMO saw is already too big. Every project has a best solution on both the method of making the hole and the type of mount (thick surface, high frequency, etc) for the job and it varies with application.
 

prcguy

Member
Joined
Jun 30, 2006
Messages
15,228
Location
So Cal - Richardson, TX - Tewksbury, MA
I'm in the LA Harbor area, if the OP wants to drive here I will be happy to put a 3/4" hole in for an antenna. I have hole saws and Greenlee punches.
prcguy

Orange County, that is south of me and over the hill. If you want to go up to San Gabriel Valley I still do the antenna mounts. Drill or punch, I have both.
 
Last edited:
Status
Not open for further replies.
Top