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by davidll1984 Wed Jun 07, 2023 9:22 am
Cox Engine of The Month
Screws for your engines..
Page 1 of 1
Screws for your engines..
In "general"... do you have spare hardware for "mounting" your various engines? Do you know the mounting-screw-size for all of the different engines that you have.. and might run someday? Do you have these screws with matching blind-nuts, lock-nuts and/or threaded-inserts for the various screw-sizes? It's always best to have the correct size hardware for safety-sake when mounting an engine.
Do you have spare machine-screws in odd sizes/head-styles; just in case you decide to rebuild an engine that has damaged screws? How about spare prop-screws/nuts?
There's few things worse in this hobby...... than not having what you need.. when you need it.
Being the obsessive personality that I am; I "try" to keep an inventory of the hardware that I might need, even if it's just a "list" of screw-sizes by engine-type, for a handy reference.
It's becoming more difficult to source small machine-screws these days.. especially in custom head-styles. If they're #4 or smaller.. you won't find them "down the street" at the hardware store.
It's time well-spent; to research and examine what you "have" and what you "may need".. if you have plans for any of your model-engines in the future. There are suppliers on the internet, that stock "hard to find" hardware. It's wise to look ahead.. and shop-around for the best prices/selection, so you might STOCK-UP NOW... in order to prevent frustration later-on. Think about the hobby items that you spend $ on.. "more kits".. "more engines".. "more building-stock".. $25.. $50.. $100+
Why not spend some time and $$ on the hardware that will help get the engines that you already have, running and mountable into an airframe? Small hardware organizers can be had for $1 at the "dollar-store".. (you can find them..) and they are worth the $$
Here's some of the hardware items that I like to have handy... (not only screws..)




and remember.... you can always cut and dress a machine-screw "shorter" if you can't source the exact length that you need.
Do you have spare machine-screws in odd sizes/head-styles; just in case you decide to rebuild an engine that has damaged screws? How about spare prop-screws/nuts?
There's few things worse in this hobby...... than not having what you need.. when you need it.
Being the obsessive personality that I am; I "try" to keep an inventory of the hardware that I might need, even if it's just a "list" of screw-sizes by engine-type, for a handy reference.
It's becoming more difficult to source small machine-screws these days.. especially in custom head-styles. If they're #4 or smaller.. you won't find them "down the street" at the hardware store.
It's time well-spent; to research and examine what you "have" and what you "may need".. if you have plans for any of your model-engines in the future. There are suppliers on the internet, that stock "hard to find" hardware. It's wise to look ahead.. and shop-around for the best prices/selection, so you might STOCK-UP NOW... in order to prevent frustration later-on. Think about the hobby items that you spend $ on.. "more kits".. "more engines".. "more building-stock".. $25.. $50.. $100+

Here's some of the hardware items that I like to have handy... (not only screws..)




and remember.... you can always cut and dress a machine-screw "shorter" if you can't source the exact length that you need.
Re: Screws for your engines..
You've got a great collection of useful stuff. I tend to save bits and pieces of everything --- the only downside is when I need it, I can't find it.
Re: Screws for your engines..
andrew wrote:You've got a great collection of useful stuff. I tend to save bits and pieces of everything --- the only downside is when I need it, I can't find it.
Thanks Andrew. I try to keep my materials organized.. but I lose things too. My shop has become terribly cluttered. One thing that I try to do is to always put things "back" where they came from.. even if it's just one leftover #2 flat-washer. I label EVERYTHING....

Re: Screws for your engines..
A few years back I found some different sources for bulk small fasteners and bits of kit
RTL at the time had a Black Friday discount that was too good to pass up
Check out
https://www.rtlfasteners.com/
Take a peek of the Master Builder assortment
I got it for $89 on Black Friday two years ago
create account
Wait for deep discount e-mails
RTL at the time had a Black Friday discount that was too good to pass up
Check out
https://www.rtlfasteners.com/
Take a peek of the Master Builder assortment
I got it for $89 on Black Friday two years ago
create account
Wait for deep discount e-mails
fredvon4- Top Poster
Posts : 3988
Join date : 2011-08-26
Age : 67
Location : Lampasas Texas
Re: Screws for your engines..
andrew wrote:You've got a great collection of useful stuff. I tend to save bits and pieces of everything --- the only downside is when I need it, I can't find it.
No wait I’m the King of can’t find it
crankbndr- Diamond Member
- Posts : 2988
Join date : 2011-12-10
Location : Homestead FL
dckrsn- Diamond Member
Posts : 2750
Join date : 2010-10-21
Age : 70
Location : Long Island, New York
Re: Screws for your engines..
That's a nice selection there Bob. Years ago, a friend of mine got me a small bagful of 5-40 x 1.25" round-head slotted machine screws for my Cox .049 engines. They came from Electronic Fasteners, Inc. in Waltham, MA. There were approx. 50 screws.. and I'm down to less than a dozen in the bag. They're a tad long for mounting a Tee Dee spinner.. so I usually shorten them with a Dremel-tool/cut-off wheel. They are however; handy for building marine-drives.. where a longer screw may be needed.
I more recently sourced a bagful (100) of 5-40 hex-nuts from Fastenal.

I used to buy packages of 2-56 assorted-length round-head slotted-screws and nuts from Radio Shack but sadly...... most of the stores have closed. I use that size mostly for mounting the Dubro small-size steel L/G straps on my 1/2A "profile" airplanes. The straps come with #2 sheet-metal screws.. which I save for other purposes.
I use a lot of "tiny" flat-washers.. and I'm finding that it's easier to make my own by using thin sheet-plastic and drilling the required ID.. then using a paper-punch to punch them out.
Re: Screws for your engines..
It's a bit of a curse coming from an early background in engineering labs with exhaustive stock of all this hardware.
Anyone on here from the Poughkeepsie, NY area, Sarjos is my go-to place. They're even open on Sat a.m., you can't beat that.
All 2-56, 4-40 hardware in stock - blind nuts, locking nuts - they have it all.
I like buying well ahead, too, like you. Having the right hardware is a luxury much enjoyed.
I do buy from RTL when they are AMA East, though. Nice to have them supplying the hobby.
Anyone on here from the Poughkeepsie, NY area, Sarjos is my go-to place. They're even open on Sat a.m., you can't beat that.
All 2-56, 4-40 hardware in stock - blind nuts, locking nuts - they have it all.
I like buying well ahead, too, like you. Having the right hardware is a luxury much enjoyed.
I do buy from RTL when they are AMA East, though. Nice to have them supplying the hobby.
PeterJGregory- Gold Member
- Posts : 144
Join date : 2014-07-28
Age : 60
Location : Hudson Valley, New York
Re: Screws for your engines..
Thanks Peter. May be up that way to walk the bridges soon.PeterJGregory wrote:It's a bit of a curse coming from an early background in engineering labs with exhaustive stock of all this hardware.
Anyone on here from the Poughkeepsie, NY area, Sarjos is my go-to place. They're even open on Sat a.m., you can't beat that.
All 2-56, 4-40 hardware in stock - blind nuts, locking nuts - they have it all.
I like buying well ahead, too, like you. Having the right hardware is a luxury much enjoyed.
I do buy from RTL when they are AMA East, though. Nice to have them supplying the hobby.
I'll give it a shot. Meanwhile, here's the site.
https://sarjo.com/
Bob
dckrsn- Diamond Member
Posts : 2750
Join date : 2010-10-21
Age : 70
Location : Long Island, New York
Re: Screws for your engines..
I previously mentioned being low on 5-40 machine-screw stock.. so I decided to order some hardware that I've wanted/needed for a while now.
5-40 black-oxide cap-screws to mount Cox .049 propeller. I chose to buy a qty. of 100 at 1" length.. and trim/cut the length to suit the app. These were sourced from "Fastenall" and are made in USA (Connecticut) by HoloKrome.

They fit beautifully with precision.. no slop whatsoever.

I was once told..... that installing the "longest-length" possible prop-screw; would strengthen the nose of the crankcase in the event of a model-aircrafts' nose-in crash on a hard-packed surface. I also have 5-40 hex-nuts.. and install them prior to trimming a screw shorter. The nut removes any burr(s) when it's removed afterward. I usually use a Dremel-tool with a cut-off wheel to shorten the length of small machine-screws. Installing two nuts of the same screw-size makes it easy to clamp the work in the edge of a bench-vise for cutting the screw.

I also ordered some 3-48 black oxide cap-screws in 1" length.. and 3-48 nylon-insert locknuts. These are the correct size for mounting Cox .049/.051 Tee Dee/Medallion engines.

Again; I ordered longer-length screws.. and will cut their length to suit.
Lastly.. I ordered some steel flat-washers. #2 size.. and also 0-80 which would be a precision-fit on .0625" music-wire.
I find many of these items to be indispensable when it comes to building 1/2A size model airplanes.
5-40 black-oxide cap-screws to mount Cox .049 propeller. I chose to buy a qty. of 100 at 1" length.. and trim/cut the length to suit the app. These were sourced from "Fastenall" and are made in USA (Connecticut) by HoloKrome.

They fit beautifully with precision.. no slop whatsoever.

I was once told..... that installing the "longest-length" possible prop-screw; would strengthen the nose of the crankcase in the event of a model-aircrafts' nose-in crash on a hard-packed surface. I also have 5-40 hex-nuts.. and install them prior to trimming a screw shorter. The nut removes any burr(s) when it's removed afterward. I usually use a Dremel-tool with a cut-off wheel to shorten the length of small machine-screws. Installing two nuts of the same screw-size makes it easy to clamp the work in the edge of a bench-vise for cutting the screw.

I also ordered some 3-48 black oxide cap-screws in 1" length.. and 3-48 nylon-insert locknuts. These are the correct size for mounting Cox .049/.051 Tee Dee/Medallion engines.

Again; I ordered longer-length screws.. and will cut their length to suit.
Lastly.. I ordered some steel flat-washers. #2 size.. and also 0-80 which would be a precision-fit on .0625" music-wire.
I find many of these items to be indispensable when it comes to building 1/2A size model airplanes.
Re: Screws for your engines..
I have always found the prop screw of my TD020 engines with spinner hubs/rubber spinners too short...(I am not talking about the ones with the aluminum spinner)..living in an SI environment in Europe and not having screws made based on the imperial metrics used in the US, I had to look for foreign sources of longer prop screws, and found Bernie's Cox 049 Engine Mounting 3-48 X 1/2" Socket Head Screws excellent as a replacement. Longer than the stock slot head screw that comes with the rubber spinner on TD020-s, this is also a socket head that allows better prop tightening than the slot head stock one, let alone the reinforcement it adds to the engine nose Roddie just mentioned.....
I wish I could have the same solution but bigger size for my 049 engines that Roddie just introduced above. I have one socket head screw in one of my TD09-s.
The slot headed prop screws not only get their slots dented sooner or later, but when the screwdriver tip slips out of the slot head, it will dart most likely into your other hand holding the engine..
Long live socket head screws...
I wish I could have the same solution but bigger size for my 049 engines that Roddie just introduced above. I have one socket head screw in one of my TD09-s.
The slot headed prop screws not only get their slots dented sooner or later, but when the screwdriver tip slips out of the slot head, it will dart most likely into your other hand holding the engine..
Long live socket head screws...
balogh- Top Poster
Posts : 4433
Join date : 2011-11-06
Age : 64
Location : Budapest Hungary
Re: Screws for your engines..
Just sent an email to Bernie encouraging him to offer socket head prop screws for all COX engine sizes on his webshop counter...but Matt is also welcome to offer them...I for one would definitely be a buyer of these items.
balogh- Top Poster
Posts : 4433
Join date : 2011-11-06
Age : 64
Location : Budapest Hungary
Re: Screws for your engines..
Although we would agree that the socket head screws are great, we have discontinued them due to extremely poor sales. We finally got rid of the last ones in 2017 and, looking back at our sales, it took us 3 years to sell 25 packs of two for the short .049 version and 2.5 years to sell 50 packs of two for the long .049 version (black and stainless steel combined).
049 screws outsell 020 version by at least 10 to 1 and the ratio is much higher for the other engine sizes, meaning that 25 packs of 020 screws will probably take us 5 years to sell.
049 screws outsell 020 version by at least 10 to 1 and the ratio is much higher for the other engine sizes, meaning that 25 packs of 020 screws will probably take us 5 years to sell.
Re: Screws for your engines..
balogh wrote:Just sent an email to Bernie encouraging him to offer socket head prop screws for all COX engine sizes on his webshop counter...but Matt is also welcome to offer them...I for one would definitely be a buyer of these items.
I have a good idea!!
Why not look at it the other way around. The best way to solve this bolt issue is to produce a batch of crankshafts with an M3 thread. This gives 2 advantages:
1) M3 is available all over the world
2) The pitch of M3 thread is finer than the the pitch of 5-40.
OVERLORD- Diamond Member
- Posts : 1686
Join date : 2013-03-19
Age : 56
Location : Normandy, France
Re: Screws for your engines..
Try McMaster-Carr. They have just about any type of screw your heart might desire. Actually, they have just about anything. I buy screws in bulk, cable for C/L flying, teflon spaghetti tubing to use with CA bottles, shim stock, taps and dies, etc.
Their site is: McMaster.com
Their site is: McMaster.com
Re: Screws for your engines..
andrew wrote:Try McMaster-Carr. They have just about any type of screw your heart might desire. Actually, they have just about anything. I buy screws in bulk, cable for C/L flying, teflon spaghetti tubing to use with CA bottles, shim stock, taps and dies, etc.
Their site is: McMaster.com
I know this company. I inquired with them in March 2015 about buying bolts and shipping. This is the answer I got:
"Hi Lieven,
Thank you for considering McMaster-Carr for your purchase. However, due to the cost of complying with extensive US export regulations, McMaster-Carr accepts international purchases only from our established customers overseas.
Jason"
This is a "I-can't-be-bothered" answer. If a person can't buy something, how can he become an established customer??
OVERLORD- Diamond Member
- Posts : 1686
Join date : 2013-03-19
Age : 56
Location : Normandy, France
Re: Screws for your engines..
A quick search came up with a fairly local supplier I've never come across before.
http://www.microfasteners.com.au/
Looks like they have a pretty good range of small machine and socket head screws in quite a few thread types. They even have a range in the common U.S. measurement of gauge/TPI (eg. 4/40) which is relatively unfamiliar to us out here.
I'm well familiar with that response Lieven. In todays "global community" type of world, there's nothing to be scared of in sending things overseas, but I have found that American sellers appear to be the most cautious about selling to "far-flung" foreign places. No offence USA folks, but it's true. It seems that a lot of people think that Australia is some little back-water place that's so far away that it may as well be on the moon. We stopped delivering the mail by horeseback a while back now.
But seriously, I try to source the best deal for my customers on car parts and often turn to overseas suppliers. My most recent "big" purchase was a part for a Jeep Grand Cherokee. Plenty of U.S. Jeep suppliers had the part at around $400 AUD, but wouldn't ship. The same part from Jeep Australia was $2,000. Found one at a Jeep supplier in Greece for under $1,000 and had it in my hand in six days, only a couple of days more than they claimed it would take to get from Sydney.
Go figure
Who's making all that extra money in the middle? To an American I paid $600 too much, but to my customer I saved him $1,000. A win for customer, a win for me, a win for the Greek seller but a big lose for the U.S. suppliers. It's really not that difficult.
Hey, don't get me wrong. I love my American (and other CEF) mates. You're all very special to me, generous and are always willing to help if asked, but business just doesn't seem to have caught up with the global market.
http://www.microfasteners.com.au/
Looks like they have a pretty good range of small machine and socket head screws in quite a few thread types. They even have a range in the common U.S. measurement of gauge/TPI (eg. 4/40) which is relatively unfamiliar to us out here.
OVERLORD wrote:
This is a "I-can't-be-bothered" answer.
I'm well familiar with that response Lieven. In todays "global community" type of world, there's nothing to be scared of in sending things overseas, but I have found that American sellers appear to be the most cautious about selling to "far-flung" foreign places. No offence USA folks, but it's true. It seems that a lot of people think that Australia is some little back-water place that's so far away that it may as well be on the moon. We stopped delivering the mail by horeseback a while back now.
But seriously, I try to source the best deal for my customers on car parts and often turn to overseas suppliers. My most recent "big" purchase was a part for a Jeep Grand Cherokee. Plenty of U.S. Jeep suppliers had the part at around $400 AUD, but wouldn't ship. The same part from Jeep Australia was $2,000. Found one at a Jeep supplier in Greece for under $1,000 and had it in my hand in six days, only a couple of days more than they claimed it would take to get from Sydney.
Go figure

Hey, don't get me wrong. I love my American (and other CEF) mates. You're all very special to me, generous and are always willing to help if asked, but business just doesn't seem to have caught up with the global market.
Oldenginerod- Top Poster
- Posts : 3831
Join date : 2012-06-15
Age : 60
Location : Drouin, Victoria
Re: Screws for your engines..
OVERLORD wrote:andrew wrote:Try McMaster-Carr. They have just about any type of screw your heart might desire. Actually, they have just about anything. I buy screws in bulk, cable for C/L flying, teflon spaghetti tubing to use with CA bottles, shim stock, taps and dies, etc.
Their site is: McMaster.com
............
This is a "I-can't-be-bothered" answer. If a person can't buy something, how can he become an established customer??
A Catch 22 situation if you know what I mean

balogh- Top Poster
Posts : 4433
Join date : 2011-11-06
Age : 64
Location : Budapest Hungary
Re: Screws for your engines..
andrew wrote:Try McMaster-Carr. They have just about any type of screw your heart might desire. Actually, they have just about anything. I buy screws in bulk, cable for C/L flying, teflon spaghetti tubing to use with CA bottles, shim stock, taps and dies, etc.
Their site is: McMaster.com
Hi Andrew, I have ordered from McMaster-Carr.. but only via a "ship-to" address of an established company where I could receive the parcel. It used to be that McM-C. wouldn't even ship to a "domestic" residential address. It shouldn't make any difference.. but could possibly be from a time where they required their customers to have an account.. and use a purchase-order. My last order was at least five years ago.. and was shipped to a machine-shop where I was currently working. I didn't need to have an account/P.O. but I have yet to list a residential ship-to address.
Were you able to have your goods shipped to your home address?
Re: Screws for your engines..
Roddie --
I expect you're quite right. All the times I had ordered from McMaster, I had the parcels shipped to my office address and we did have an established account. It never occurred to me that local or private buys were disallowed.
I have not ordered since I retired --- I hate finding that out.
andrew
I expect you're quite right. All the times I had ordered from McMaster, I had the parcels shipped to my office address and we did have an established account. It never occurred to me that local or private buys were disallowed.
I have not ordered since I retired --- I hate finding that out.
andrew
Re: Screws for your engines..
I have stuff from McMaster shipped to my home address. Ordered a bunch of stuff from them for my 3D printer - metric hardware. All my metric tap sets for fixing my OS engines came from McMaster too.
I was looking at their 2-56 filister head selection but they only go to 1" long. Looks like Amazon has packs of 100 in the lengths I need for the stunt tanks. They need to be trimmed though as they are a fuzz too long.
I was looking at their 2-56 filister head selection but they only go to 1" long. Looks like Amazon has packs of 100 in the lengths I need for the stunt tanks. They need to be trimmed though as they are a fuzz too long.
Jason_WI- Top Poster
Posts : 3123
Join date : 2011-10-09
Age : 47
Location : Neenah, WI

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