# Turning square headed bolts



## neil_1821 (Jul 16, 2018)

Thought I’d post this as everyone has their own methods.

On my next project, in order to keep in scale to the full size there is a requirement to have square headed bolts, more precisely over 300 of them. 

They are not commercially available to buy so that means I’ve got to make them and I’m wondering what method would be best to use in order to keep a fairly tight tolerance on repeatability. 

I was thinking of drilling a hole in some round bar, which would be the overall diameter of the square material from corner to corner, then having bolts on either side to clamp it while I turn it and thread it then part off. If anyone can suggest any other methods I’m all ears.


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## crec (Jul 16, 2018)

Square hole collet would be best if you have it. Quick and repeatable.


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## neil_1821 (Jul 16, 2018)

I didn’t know you could get square hole collets! 

We do have a collet set so this could actually be quite viable if I can find one to fit


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## Naiveambition (Jul 16, 2018)

My take is you have square material already?   
 As of now the image projected onto my eyeballs is to turn from round and thread, then make a split threaded collet (square)  , then use vise to squeeze the thread and flip for each side, milling just the edges.    
Just a suggestion

300 threaded wow,  I would prob turn green seeing that number


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## neil_1821 (Jul 16, 2018)

I haven’t got the material yet, I’m just tossing some ideas round to see what the best way is. It doesn’t help that the top face isn’t flat. Although it is a square headed bolt the face of the square will be slightly curved so will have to grind the right profile on the parting off tool. Thinking that a square collect might be best as they hold the material fairly central, more so than a 3 jaw chuck, which is handy for how small the bolts will be.


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## MachineTom (Jul 16, 2018)

You did not say the size. If you have a collet holder, you can buy square collets up to 7/8" for 5ç collets. You can take a round bar mill a groove the size of the square, then mill a piece to fill the slot, use set screws to hold the stock.
A 4 jaw Chuck is slower than the others, but works.
Drill the depth of 4-5 nuts, tap the hole. Then profile, then part off. 

I did a dozen nuts for a scale project. For 300 look around on the net. A guy with a turret lathe could knock those out fairly quick.


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## MachineTom (Jul 16, 2018)

I forgot to say that you then thread the nuts on to studs, thread them until they jam, cut the stud not quite flush, then peen the stud, hit it with a belt sander, look like it was old.


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## bazmak (Jul 16, 2018)

4 jaw self centering chuck are readily available.I bought one when making the turners cubes
and now use it all the time.Holds sq and round, use 3 jaw for hex and round


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## Wizard69 (Jul 17, 2018)

What size bolts are you talking about?   You should be able to find them someplace on the net.   If not bolts, nuts are certainly available especially in the smaller sizes used in automation extrusions.  You could easily weld the nuts to threaded rod.  

Unless you are extremely patient, i cant see doing this on home shop equipment.   Maybe 30 but 300 would drive me nuts.  

Interestingly i believe it was Mr Pete that ran some videos on making square head bolts.  If i recall correctly they where flanged bolts for a tool post so maybe not what you need.   In any event the general idea is good, which is to use round stock that can inscribe the bolt head.   The nice thing here is that the square can be simply done with a collet block on a mill or even a lathe.


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## neil_1821 (Jul 17, 2018)

The thread is probably going to be around M3/M4 so the head has to be fairly concentric to the shaft. As you can see on the picture they’ll be used everywhere on the engine, although the builder of this has used some hex headed ones we intend to stick with square. I don’t think patience is an issue, I can make some, do a bit more machining on the wheels then come back when I need a break.


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## Baner (Jul 17, 2018)

Here's an article on making square adaptors for round collets: http://www.homews.co.uk/page75.html

 Looking at that photo, a lot of those bolts look decorative; in that situation you could just make square head rivets, (ie: no thread) drill a hole and soft solder  them in place. It would be much quicker than threading and tapping.


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## neil_1821 (Jul 17, 2018)

Thanks for the link Baner. 

I haven’t ruled out the possibility of using square head rivets, but being a double frame construction there will still be a considerable amount that need to be threaded. I think this will be a case of seeing how I get on. I’ll have to post some pictures and further info on my build page when I get round to starting it again.


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## johwen (Jul 17, 2018)

neil_1821 said:


> Thought I’d post this as everyone has their own methods.
> 
> On my next project, in order to keep in scale to the full size there is a requirement to have square headed bolts, more precisely over 300 of them.
> 
> ...


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## johwen (Jul 17, 2018)

Hi,

I use a four jaw self centering chuck and this makes it easy. 

In fact I only have a 4 jaw self centering chuck for all my concentric turning, more accurate, and will hold even hex accurately.

Hope this helps!
John


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## MachineTom (Jul 17, 2018)

With that size bolt, just make them out of square stock. Get a threading head, small sizes often cheap on eBay.

Very easy to use.


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## Wizard69 (Jul 21, 2018)

I can find square head bolts down to 1/4-20 all day long.  Im not sure how the head sizes compare to M4 bolts  but if they are not too far off you might be able to easily trim the head to the size needed by the model.  

Mind you those where found in the common places.   If you look around you might find square head machine screws in size 10-32.   When all else fails call some of the bigger vendors to see if they have a line on stock or special orders.  As noted before square nuts can be found due to their use in automation extrusions.


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## tjwal (Jul 24, 2018)

Would regular hex head bolts have enough meat in the head to look correct if milled square?


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## neil_1821 (Jul 24, 2018)

tjwal said:


> Would regular hex head bolts have enough meat in the head to look correct if milled square?



Unfortunately not. I know you can get bolts with different sized heads, but it’s more the width of the head as well as the profile of it. 

I think I’ll end up using a collet chuck as detailed in the link further up the page.


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## kquiggle (Jul 25, 2018)

Here are a couple of crazy ideas:

Forged head: Take a set screw of the appropriate size, heat the end red hot, and using a purpose-made square punch and holder pound the head square.






Add head to set screw: Start with a length square stock of the appropriate size; drill and thread for an M3 set screw. Thread the set screw into the square stock to a bit longer than head height, using permanent thread lock. Cut of the square head so that you cut through the set screw also; hopefully the join will be almost invisible. This will leave a bit of set screw in the remaining square stock - just cut off the end of the stock to remove it, and repeat with the next set screw (alternatively, you could insert the set screw into the stock hex-end first; then use a hex wrench inserted through the square stock to back out the left-over end.


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## colby15642 (Jul 25, 2018)

Everyone seems to want to do extra work!  A new Chi-Com 5C square collet, either metric or Imperial is about $15 or less.  Square 12L14 free machining stock is probably available, although regular key stock will machine easily enough.  Three hundred screws is a lot, but at about 7 minutes each, with quick-change tooling, is 35 hours or a short week, not including beer breaks.  You will need to chuck each screw twice, the second time with a round collet to nicely contour the top of the screw head with a form-shaped tool.


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## Jasonb (Jul 25, 2018)

I tend to turn the thread on some round stock, thread and then over to the spin indexer in the mill to square them off. If you work both ends of 2 or 3 lengths of rod you are not constantly back and forth. Also gives nice square corners to the fixings as some square stock can be a bit rounded. Once squared saw them off and then when you have  a batch just hold in 3-jaw and face them all off to the length required, a form tool could do that and add any specific chamfer.












GHW sell square nuts in the small metric sizes but they use the standard AF size, I think one size smaller looks better like their hex fixings.

https://ghw-modellbau.de/index.php?cPath=18_21


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## colby15642 (Jul 25, 2018)

I concur with your comments about the imperfect corners on commercial square stock.  Nice finish on y6ur fasteners!


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## neil_1821 (Jul 25, 2018)

Thanks for all the suggestions, greatly appreciated. I will make a start on them at some point, those who are in the UK know how hot it is recently and being in a small stuffy workshop at night probably isn’t the best idea after a long day at work. Hopefully make a start this weekend. 

Very nice fasteners Jason, and the square nuts certainly add a little something


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## bazmak (Jul 25, 2018)

I agree,but would use a 4 jaw self centering chuck and hot rolled sq stock depending on availabilty and size
What is the head size. Keep it simple,these alternative ideas would probably work but take as least as long
If a std thread size screw is available can an available and suitable head be used for milling down ?


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## Wizard69 (Jul 25, 2018)

colby15642 said:


> I concur with your comments about the imperfect corners on commercial square stock.  Nice finish on y6ur fasteners!



Key stock is the key here    In order for it to be useful key stock must be of precision size with high quality edges.   

How lets consider what the heads of bolts look like in the field.  Most show at least some signs of distress so imperfect corners would simply reflect the prototypes.


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## john_reese (Jul 25, 2018)

I have a South Bend 10K with a 4 jaw scroll chuck, bed turret, die hed and lots of chasers.  The chasers are all American standard sizes.  It is a perfect setup for the job.  Do you waant to e-mail me a drawing?


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## bazmak (Jul 26, 2018)

I agree that sq bar with slight rad cnrs and small imperfections would add to the look


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## TonyM (Jul 26, 2018)

If you must make from solid then the only sensible way is to turn from square stock. You can make a simple split collet for holding in 3 jaw. If you are open to other methods then why not just buy  standard square nuts and studding. Cut studding to length and a drop of soft solder / loctite to finish. Otherwise buy 1000 from China. Cheap as chips.


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## abby (Jul 26, 2018)

I make dozens of 4BA square heads for my miniature quick change toolposts , I have a Pultra lathe with capstan turret and a coventry die head.
Email me a drawing and I will quote if you like .
Dan.


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## deverett (Jul 26, 2018)

A lot of the answers don't seem to take into consideration the size of the heads or threads required.
Firstly, is square material available in the size required?

If not the options are to mill down a size larger square then hold the newly formed correct size in a square collet, ready to hand or probably more likely home made.  The original idea of securing square stock in a drilled hole with set screws could end up damaging the bolt faces.
If that is not a practical solution, then the only other way is to start with round bar and turn that down to the across corner dimension;  make lots of bolts with the round heads then hold the embryo bolts by the turned shank and square off the head with an end mill in whatever milling facilities are available.  Ditto repeato until the 300 or so (+ a few spare!) are done.

Dave
The Emerald Isle


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## Richard Carlstedt (Jul 26, 2018)

Made lots of square and hex bolts and nuts.
For square head I use precision ground Key stock ( 0-1 ) and a regular 4 jaw chuck.
Center the stock and mark with white paint the space between 2 jaws. Always stop and loosen/tighten only those jaws and you will be fine and it is faster than a collet setup.
I have box tool I made based on a Modeltec Article of about 20 years ago that supports the stock while turning it to size and length, and then you mount the die on a pilot at the front of the box tool  and thread the bolt, all without shutting off power. takes only 5-10 seconds , then remove the box tool from the Aloris post and drop in a cutoff tool and you have the bolt.

Rich


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## Cymro77 (Jul 26, 2018)

This gets stranger and stranger - I can't wait to see the outcome and path chosen!  Unfortunately I have nothing helpful to add, I do like the simplicity of the self centering four jaw chuck and square stock.


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## DJP (Jul 26, 2018)

An option not presented is to do keep it simple. If the square head bolts are cosmetic only then leave them off the model and if they are functional then hex head bolts painted over would not offend me. I doubt that bolt heads are the main design aspect of the model to which the observer's attention needs to be drawn. 

Purchasing square headed bolts in a size close enough might also be considered a keep it simple approach. 

I too would like to see the final solution chosen by the OP.


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## pramponi (Jul 27, 2018)

neil_1821 said:


> I didn’t know you could get square hole collets!
> 
> We do have a collet set so this could actually be quite viable if I can find one to fit


Pretty sure Grizzly has them so I'm sure they're common. Also hex.


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## dnalot (Jul 27, 2018)

McMaster-Carr has some square headed bolts down to 10-24, but with a round top flange that could easily be milled off. 

https://www.mcmaster.com/#carriage-and-plow-bolts/=1dwa1ux

Mark T


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## john_reese (Jul 28, 2018)

You might be able to do them in one chucking.  Use a form tool to shape the corners then part off.


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## nel2lar (Jul 28, 2018)

Neil
Have you entertained the idea of making a square collet and a custom parting tool to finish the head of the bolt. I think the time to be a lot less than the 7 minutes. If is going to make a big difference on your set up.
Good luck, I'll be watching
Nelson


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## neil_1821 (Jul 28, 2018)

Nelson,

Yes I have though about making a square collet, and i was intending on profiling the parting of took to finish the shape as it’s parted off. Since most of these bolts are only decorative I’ve decided to just make them an interference fit rather than threading, which I think will save a lot of time. 

I’ll update my build thread accordingly when I get round to doing some. Thanks to everyone for the suggestions and advice/offer of help. Greatly appreciated.


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## larryg (Jul 28, 2018)

https://www.amazon.com/dp/B00GWOVW3M/?tag=skimlinks_replacement-20

A friend making a bunch of hex bolts took a piece of drill rod and cut the end into a hollow mill by drilling the hole the size of the bolt shank and cutting the flutes with a dovetail cutter.  The OD of the cutter was the size to hold a tailstock die holder;
https://littlemachineshop.com/products/product_view.php?ProductID=2314 .  He used stock the size of the bolt head, and a hex collet.  With this he went into production.  Pull the stock out to the bolt length, turn the OD of the material to size, slip on the die holder and thread to length.  Part it off with with a parting tool and spin the head against a belt sander to knock off the corners of the top.  

He also informed us that he drilled from the back of the cutter to leave just a small section where the shank was guided to reduce friction.

lg
no neat sig line


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## nel2lar (Jul 29, 2018)

Neil
As small as they are what about a form tool to do both the cylindrical part and the head-part off, all at the same time? Pop them out like popcorn!!!
Nelson


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## john_reese (Jul 30, 2018)

I can get it in one chucking.  Bed turret set up work stop chamfer tool, then hollow mill or box tool to turn the diameter, last the die head to thread the shank.
The square turret on the cross slide has a form tool to chamfer the square , and a part off tool ground to leave the pip on the work in the chuck.


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## john_reese (Jul 30, 2018)

The screws could also be made from round using a rotary broach to form the square.  That gives a lot more flexibility in the choice of material.


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## nel2lar (Jul 30, 2018)

The rotary broach seems to be the best so far, broach turn down the press fit and part off. 
Nelson


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## TonyM (Jul 31, 2018)

Slow down guys. This is for 300 bolts. A half decent rotary broach + tooling is not cheap.


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## joshsapp (Jul 31, 2018)

Richard Carlstedt said:


> Made lots of square and hex bolts and nuts.
> For square head I use precision ground Key stock ( 0-1 ) and a regular 4 jaw chuck.
> Center the stock and mark with white paint the space between 2 jaws. Always stop and loosen/tighten only those jaws and you will be fine and it is faster than a collet setup.
> I have box tool I made based on a Modeltec Article of about 20 years ago that supports the stock while turning it to size and length, and then you mount the die on a pilot at the front of the box tool  and thread the bolt, all without shutting off power. takes only 5-10 seconds , then remove the box tool from the Aloris post and drop in a cutoff tool and you have the bolt.
> ...



One other way is to use three of the four jaws to clamp a vee block. The fourth jaw will hold the square stock against the vee block. This way you only have to loosen one jaw and gives a positive register for the stock.


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## Kevinb71 (Aug 3, 2018)

Richard Carlstedt said:


> Made lots of square and hex bolts and nuts.
> For square head I use precision ground Key stock ( 0-1 ) and a regular 4 jaw chuck.
> Center the stock and mark with white paint the space between 2 jaws. Always stop and loosen/tighten only those jaws and you will be fine and it is faster than a collet setup.
> I have box tool I made based on a Modeltec Article of about 20 years ago that supports the stock while turning it to size and length, and then you mount the die on a pilot at the front of the box tool  and thread the bolt, all without shutting off power. takes only 5-10 seconds , then remove the box tool from the Aloris post and drop in a cutoff tool and you have the bolt.
> ...



I have not heard of a "box tool" and would like to see some pictures. Thanks!


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## TonyM (Aug 3, 2018)

Obviously I didnt read the post properly .


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## nel2lar (Aug 3, 2018)

Richard
I would love to see some pictures, it seem like you have a very special box tool?
Nelson


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## kf2qd (Aug 3, 2018)

Use round stock of sufficient size, get one of the square collet blocks and mill the square. Much easier to use squatre stock and use a square collet...


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