Model sized nuts

[oldengineguy]

Where can you buy model size nuts that look right on small engines? I am looking for 4-40 &6-32 in particular but could use other sizes if available. Thanks Colin

 

[stevehuckss396]

Go to mcmaster carr's website and search for nuts. They have nuts in many different styles like hex, square, acorn. There are nuts that have a smaller hex than standard. Also they have thinner than standard. all kinds.

 

[Gordon]

McMaster Carr has narrow hex nuts which are smaller than the standard hex.

 

[joerom]

American Model Engineering – Godshall's Custom Machining & Live Steam (godshallscustommachining.com)

 

[trlvn]

Where can you buy model size nuts that look right on small engines? I am looking for 4-40 &6-32 in particular but could use other sizes if available. Thanks Colin

You might want to check Spaenaur in Kitchener, ON. They have an extensive selection of hardware. For example, they have 4-40 hex nuts in steel, brass, stainless steel and aluminum with 2 sizes (across the flats) and 2 thicknesses. Although not all combinations and permutations:

https://spaenaur.com/wp-content/uploads/2018/02/Hex-Nuts-C2-C15.pdf
I believe they sell small quantities at their counter but I've never actually done that.

Craig

 

[GregNixon]

If you really want nuts to look authentic then look at the BA range. Unfortunately these are now being or have been phased out. The nice thing about BA is it scales up and down by a fixed fraction. That means a 0BA screw/nut will have the same look as a 2BA screw nut.

I have seen charts that attempt to replace BA with metric, unc, unef etc. It just doesn't work well. If you have the plans for Westbury's Whippet, have a look at where the head bolts are. BA fits nicely but substitutes run very close to the water jacket.

BA was a metric based. OBA is 6x1.0mm. I used to have the Whippet modelled up in Inventor, I'll have a look for it.

 

[methuselah1]

Shipping shouldn't cost too much. BA is still very much alive in England, and Reeves 2000 sells fasteners of this type. They are made on sliding head automatic lathes, and their quality is a cut above what you can usually buy. They also sell "model engineers' special set screws" which are bolts with a hex head one size smaller.

Taps and dies can be bought readily from many suppliers here; I use a firm called Chronos. They sell high speed steel as well as carbon steel threading tackle; I use the latter, and I can buy a set of three taps and a die for less money than a pack of cigarettes. Carbon steel, if it doesn't get hot, is actually harder than HSS, and as a bonus, it's cheaper, too.

Reeves have been established since the beginning of time, and are the "go to" source for the majority of model locomotive builders in the UK. Chronos started up in the mid 1980s, and I remember when their shop was two garden sheds hidden behind a backstreet. They have since gone from strength to strength, in no small part due the the owners attention to customer service. Dispatch from either of these companies is PROMPT.

Usual disclaimers, of course.

Andrew UK.

 

[davidyat]

I've gotten most of my bolts and screws from Bolt Depot.

boltdepot.com

Grasshopper

 

[GreenTwin]

I have purchased model bolts in the past, but the supplier went out of business.

I bought some hex stock, and started making my own bolts and nuts.
I generally make the bolt head or nut significally taller than a store-bought nut, because the old fasteners were quite a bit taller than modern ones.

STANDARD HEX STOCK
3/16" 0.1875"
7/32" 0.21875"
1/4" 0.250"
5/16" 0.3125"
3/8" 0.375"
7/16" 0.4375"
1/2" 0.50"
9/16" 0.5625"
5/8" 0.625"
11/16" 0.6875"
3/4" 0.75"
13/16" 0.8125"
7/8" 0.875"
15/16" 0.9375"
1" 1.0"

I mount the hex in the lathe, drill with the appropriate tap size drill, tap deep enough for two nuts, and then part off, rounding the top slightly before parting. The bottom of the nut is flat.
Its pretty easy.

In the second photo, the nut on the far left is a commerical unit.

My hex stock.
I seem to recall it is free-machining material, which I guess means it has lead in it.

 

[GreenTwin]

I made some bolts from the same hex stock by turning a blank the desired length of the bolt, threading the blank part, and then parting off the bolt head in the same fashion as parting off the nuts.
Bolts are also pretty easy to make.

Here are some nuts installed.
The taller nuts with the flat bottom give an old-school look to a model, if you are after that sort of look.

.

 

[GreenTwin]

I was looking for the exact numbers that I used to make nuts and bolts for the above engine, and I am not positive of the exact numbers, but I think it was as follows. You can play around with the bolt head size; it is not critical, and also play around with the bolt head/nut height to suit your tastes.
Check me on these numbers; I can't find my official sheet.

5-40, 0.123" diameter shaft (I use 3/16" stock hex, 0.188") (not sure of the head height)

6-32, 0.134" diameter shaft, 0.10" head height (I use 7/32" stock hex stock, 0.218")

8-32, 0.166" diameter shaft, 0.125" head height (I use 1/4" stock hex, 0.25")

10-32, 0.186" diameter shaft, 0.147" head height (I use 5/16" hex stock (0.312").

#12 bolt/nut, I use 3/8" (0.374").

1/4" bolt/nut, I use 7/16" (0.436").

Edit:
For some of the bolts/nuts, you could probaby vary one hex size, if you want a slightly larger or smaller nut/bolt head for a given shaft size.

.

 

[RandyK]

Try Micro Fasteners

 

[comstock-friend]

Here is a chart I put together for bolts and washers. The hex size and height is from Godshalls (dimensions in inches):

Model Hardware​

Model Hex Cap Screws​

Scale Washers​

Drilling​

Size	Hex Used	Head Height	Washer Land	Outside Diameter	Decimal	Thickness	Clearance	Tap Drill	Percentage
#0-80	3/32”	0.040	0	1/8"	0.125	0.015"	1/16"	3/64"	97
#1-72	7/64”	0.055	0	5/32"	0.156	0.020"	48	53	90
#2-56	1/8”	0.064	0	3/16"	0.188	0.025"	43	50	85
#3-48	5/32”	0.075	0.003	7/32"	0.219	0.030"	38	46	80
#4-40	11/64”	0.084	0.004	1/4"	0.250	0.035"	33	43	85
#5-40	3/16”	0.093	0.005	9/32"	0.281	0.040"	30	38	87
#6-32	7/32”	0.104	0.006	5/16"	0.313	0.045"	28	35	83
#8-32	¼”	0.125	0.006	11/32"	0.344	0.050"	19	29	83
#10-32	9/32”	0.140	0.007	3/8"	0.375	0.055"	11	24	84

And yes, I've replaced BA hardware that came with my Stuart kits with hardware based on this chart. They look better (to me).

 

[stevehuckss396]

I think you might have to make your own if you are looking for an exact scale nut or bolt. They can be easy to make and you will be much happier when finished.

 

[oldengineguy]

Thank you all for reply & suggestions. Unfortunately Mc . Carr ,Spae- Naur et.al. only supply nuts that are min .187 af and to look right they need to be .170. I have made nuts & bolts in the past and had hoped to avoid doing that in this case. I need 50. I can't find 11/64 hex rod from the usual suppliers anyway. The only lead that has panned out is joerom American model Engineering, they list what I need. By the time I get them here in CDN.$ they will cost about a buck apiece! It may be time to re-think this project. Thanks again,Colin

 

[petertha]

If you reside in Canada, 99% chance you can stroke McMaster Carr off your list anyways. Its awesome for our American friends but their out-of-country policy for many years has been to ship only to businesses & institutions, not hobbyist mortals. Not even if you say I'm after $500 worth of whatever. They say they cant be bothered with the customs paperwork. There are some I've heard of who have mitigated this, but my guess is some form of oversight & just a matter of time.

I've heard good things about Spaenaur in Canada. They have an extensive catalog. But it seems to be a somewhat convoluted ordering process. There does not seem to be the equivalent of populating an online shopping cart & click buy. I think its forth & back emails which is about 20 years behind the times. I thought this maybe result of pandemic conditions, but actually could be their sales model. If I'm wrong, please somebody correct me. I'd love to give them business.

 

[oldengineguy]

petertha : I am fortunate enough to live 30 KM. from Spae Naur and have dealt with their counter staff for years,but don't know about their shipping first hand. They deliver locally next day ,and I know they ship to U.S. I order by phone for pick-up ,always ready on time, no hassles. BUT this time around they don't have what I need. I have a friend with a business that deals with Mc Carr but they also cannot supply needs. Godshalls American model Engineering has all the stuff Ineed , I just have to decide if I need it badly enough. $$$$$ Colin

 

[abby]

Finding the correct steel hex stock for small scale nuts and bolts is becoming difficult because mills no longer produce the exact sizes , you could try hex socket keys , anneal them and use the steel. As already said the BA range will provide most scale requirements but even these are becoming more expensive for the reason I mentioned.
I recently talked with a well known UK manufacturer and they are using hex steel that has been milled to size rather than cold drawn.
Dan.

 

[dazz]

If you reside in Canada, 99% chance you can stroke McMaster Carr off your list anyways. Its awesome for our American friends but their out-of-country policy for many years has been to ship only to businesses & institutions, not hobbyist mortals. Not even if you say I'm after $500 worth of whatever. They say they cant be bothered with the customs paperwork. There are some I've heard of who have mitigated this, but my guess is some form of oversight & just a matter of time.

McMaster is worse than that. I use a freight forwarder that has a US address. Sellers ship to it without needing to know that the item will be exported to my country. That worked great with McMaster until I went to pay with my credit card. McMaster refused to accept it (their right), so the excuse they give about customs documentation is just that, an excuse.

 

[OscarII]

If you really want nuts to look authentic then look at the BA range. Unfortunately these are now being or have been phased out. The nice thing about BA is it scales up and down by a fixed fraction. That means a 0BA screw/nut will have the same look as a 2BA screw nut.

I have seen charts that attempt to replace BA with metric, unc, unef etc. It just doesn't work well. If you have the plans for Westbury's Whippet, have a look at where the head bolts are. BA fits nicely but substitutes run very close to the water jacket.

BA was a metric based. OBA is 6x1.0mm. I used to have the Whippet modelled up in Inventor, I'll have a look for it.

While 0BA is the same size as 6 x 1.0mm, the thread profiles are different so they are not interchangeable