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SBartleet
23rd May 2006, 10:56 PM
Hi,

I am hoping to use a square stainless steel square bar as a balustrade. The ends of the square bar will protrude through a 75mm square wood post. In order to fasten the horizontal bars I need to thread the end of the bars so that I can put a nut on and pull them tight.

I am using 6.35mm (1/4") square stainless steel square bar grade T304 or T316. I am hoping to get about 50mm of thread machined onto the ends. I was hoping to do a DIY job by grinding the corners off the bar to make it mostly round and then to purchase a dye to put a thread on the end. I have 28 bars that I need to put ends on. I am trying to determine if I can get away with a M8 bolt which I believe has a 6.8mm root diameter. The diagonal length of the square bar is 8.98mm so I expect to grind off the four corners until the diagonal is 8mm and then add the thread. As the bar is only 6.35mm across the middle there will be a short flat spot on the threads on each of the four sides. I do not expect that this will be a problem as there will not be a huge load on the bars. The other option is to grind the square end to a 6mm round and tap a M6 thread on the end.
I am concerned that the dye may not last for the 28 ends that I need to do. I do not have access to a lathe. Other options include welding a short piece of threaded rod onto the end of the bar.

Any comments on the practicality of this or other suggestions will be appreciated.

Sean

journeyman Mick
23rd May 2006, 11:24 PM
Sean,
I've never tried tapping SS but I can't imagine it would be easy, especially if it's not really round. Could you drill into the post at 90deg to the SS bar and have a hole through the bar at the intersection. Drive a screw into the post so it passes through the SS bar and bites into the other side. This might look a bit neater too.

Mick

Ashore
24th May 2006, 12:25 AM
your post suggests that there is no problem in SS welding
If so then cut you problems in half by welding a good flat washer to one end of the square section then you will only have to worry about thread on the other end


The other thought maybe to pull the posts together with a long clamp mark the square section stainless drill through holes at each end say 5 mm and insert pins then release the clamp might even look good

Rgds

ariel
24th May 2006, 02:47 PM
[quote=SBartleet]Hi,

I am hoping to use a square stainless steel square bar as a balustrade. The ends of the square bar will protrude through a 75mm square wood post. In order to fasten the horizontal bars I need to thread the end of the bars so that I can put a nut on and pull them tight.

I am using 6.35mm (1/4") square stainless steel square bar grade T304 or T316. I am hoping to get about 50mm of thread machined onto the ends. I was hoping to do a DIY job by grinding the corners off the bar to make it mostly round and then to purchase a dye to put a thread on the end. I have 28 bars that I need to put ends on. I am trying to determine if I can get away with a M8 bolt which I believe has a 6.8mm root diameter. The diagonal length of the square bar is 8.98mm so I expect to grind off the four corners until the diagonal is 8mm and then add the thread. As the bar is only 6.35mm across the middle there will be a short flat spot on the threads on each of the four sides. I do not expect that this will be a problem as there will not be a huge load on the bars. The other option is to grind the square end to a 6mm round and tap a M6 thread on the end.
I am concerned that the dye may not last for the 28 ends that I need to do. I do not have access to a lathe. Other options include welding a short piece of threaded rod onto the end of the bar.

Any comments on the practicality of this or other suggestions will be appreciated.

Sean
[]

Sean,
If you buy S/S studs or bolts with nuts and have a welding machine, your job will be easier and cut in half the time or even less (its my opinion taking in consideration that you have 56 ends to thread) if you take the last option presented by you.

2.5mm 304/8 S/S electrodes for AC (240V machines) can be purchase in small quantities and 70 to 90 amps.
Distortion, can be controlled by depositing a little weld at oposite sides into a pre made 45 degrees bevel at the end of the bar or bolt/stud. Ensure no grease or oil is present in the weld joint. It will make holes in the weld and therefore the weld becomes weaker.

Ensure that the weld joint will stay inside the 75mm square post. You do the sums.

Just a reminder for you. When you tighten the nuts to tense the bar, be aware that you will be pulling the posts in if they are not held in position.

Cheers
Ariel

ariel
24th May 2006, 03:00 PM
[quote=SBartleet]Hi,

I am hoping to use a square stainless steel square bar as a balustrade. The ends of the square bar will protrude through a 75mm square wood post. In order to fasten the horizontal bars I need to thread the end of the bars so that I can put a nut on and pull them tight.

I am using 6.35mm (1/4") square stainless steel square bar grade T304 or T316. I am hoping to get about 50mm of thread machined onto the ends. I was hoping to do a DIY job by grinding the corners off the bar to make it mostly round and then to purchase a dye to put a thread on the end. I have 28 bars that I need to put ends on. I am trying to determine if I can get away with a M8 bolt which I believe has a 6.8mm root diameter. The diagonal length of the square bar is 8.98mm so I expect to grind off the four corners until the diagonal is 8mm and then add the thread. As the bar is only 6.35mm across the middle there will be a short flat spot on the threads on each of the four sides. I do not expect that this will be a problem as there will not be a huge load on the bars. The other option is to grind the square end to a 6mm round and tap a M6 thread on the end.
I am concerned that the dye may not last for the 28 ends that I need to do. I do not have access to a lathe. Other options include welding a short piece of threaded rod onto the end of the bar.

Any comments on the practicality of this or other suggestions will be appreciated.

Sean
[]

Sean,
If you buy S/S studs or bolts with nuts and have a welding machine, your job will be easier and cut in half the time or even less (its my opinion taking in consideration that you have 56 ends to thread) if you take the last option presented by you.

2.5mm 304/8 S/S electrodes for AC (240V machines) can be purchase in small quantities and 70 to 90 amps.
Distortion, can be controlled by depositing a little weld at oposite sides into a pre made 45 degrees bevel at the end of the bar or bolt/stud. Ensure no grease or oil is present in the weld joint. It will make holes in the weld and therefore the weld becomes weaker.

Ensure that the weld joint will stay inside the 75mm square post. You do the sums.

Just a reminder for you. When you tighten the nuts to tense the bar, be aware that you will be pulling the posts in if they are not held in position.

Cheers
Ariel


Sean,

I forgot to say that Ashore has a good idea as is welding the bolts/studs.
You decide.

But be aware that discolouration of the S/S will take place with welding, unless you passivate the area or use a S/S wire wheel or a S/S wire brush to polish the area.

Cheers

Ariel
___________________________________________________

KNOWLEDGE DOES NOT TAKE PLACE, ONLY MAKES ONE WISER :D

ariel
24th May 2006, 08:25 PM
Hi,

I am hoping to use a square stainless steel square bar as a balustrade. The ends of the square bar will protrude through a 75mm square wood post. In order to fasten the horizontal bars I need to thread the end of the bars so that I can put a nut on and pull them tight.

I am using 6.35mm (1/4") square stainless steel square bar grade T304 or T316. I am hoping to get about 50mm of thread machined onto the ends. I was hoping to do a DIY job by grinding the corners off the bar to make it mostly round and then to purchase a dye to put a thread on the end. I have 28 bars that I need to put ends on. I am trying to determine if I can get away with a M8 bolt which I believe has a 6.8mm root diameter. The diagonal length of the square bar is 8.98mm so I expect to grind off the four corners until the diagonal is 8mm and then add the thread. As the bar is only 6.35mm across the middle there will be a short flat spot on the threads on each of the four sides. I do not expect that this will be a problem as there will not be a huge load on the bars. The other option is to grind the square end to a 6mm round and tap a M6 thread on the end.
I am concerned that the dye may not last for the 28 ends that I need to do. I do not have access to a lathe. Other options include welding a short piece of threaded rod onto the end of the bar.

Any comments on the practicality of this or other suggestions will be appreciated.

Sean


I sent you a replyto help you out but can not see it in your thread.

Ariel

Mick C.
25th May 2006, 11:35 PM
If you decide to use a Die on the bar, i'd make sure you buy a HSS Die rather than the usual Chrome Tungsten Alloy ones as it will last a lot longer, and i'd use liberal amounts of cutting fluid or Trefolex, and when you grind the corners off a lil, i'd be very carefull not to get very much heat into it at all, is it is likely to get harder as it is heated (depending on the grade).

charter
29th Oct 2007, 04:36 PM
I've worked a lot in S/S and I would shy away from trying to thread it. Is it possible to drill the ends and attach a small turnbuckle or weld one on. They look OK and if you are using solid bar you wont be putting too much tension on as the post will give first. Pickling paste will remove any discolouring but wear gloves and glasses. You can get it from BOC.

malb
29th Oct 2007, 07:48 PM
1. 304 is a general grade material and not suited to exposed use, will 'tea stain' within weeks if exposed to weather or pollutants.

2. It is prone to hard spots that will stuff the faces on a drill even when being drilled with correct speeds, feeds and lubes. It is virtually impossible to use where production internal threads are required, as it is near imposible to drill the correct base hole and then tap it. Have not tried to cut an external thread with a die, but would not anticipate being successfull. Free machining grades are available (308?) but as expensive as 316.

3. Die will have 3 or 4 interupted cutting faces and rounded corner square will also have 4 interuptions per revolution. Dies are intended for threading continuous round material that is accurately presized, and do not like interupted cuts. I suspect that a die would be lucky to cut a single thread before chipping or breaking. Winding a chipped or broken die of a part formed thread will damage the thread anyway.

4. 1/4 sq material is very flimsy and would struggle to support its own weight if tensioned horizontally between uprights. While it might provide a cosmetic barrier, it is most unlikely to provide a safety barrier, which is the primary purpose of a balustrade.

Grahame Collins
29th Oct 2007, 08:15 PM
Hi SBartleet
If you have access to a welder should not be an issue.Welders can hired very reasonably and if you can't weld yourself there must be some one who can weld in your circle of friends and acquaintances. Failing that one of the mob from the Brisbane contingent may put their hand up to help. Stainless electrodes are much easier to start and use than the regular ones.

The easiest solution in terms of time effort and money spent has got to be the welding.

56 ends of 50mm will run out around 2.8 meters of rolled thread or 3pieces if they still sell them in 1 meter cut lengths.

2.5 mm 316L Stainless steel electrodes might be had From a sheet metal works or a small engineering shop or maybe even a welding shop catering to DIY the Brisbane boys can advise on that one maybe )

You will need :


A hacksaw
A file
A welder and helmet & gloves
A bit of a knock up jig to align said sq bar and the thread
3 x 1 meters of 6mm 316 roll thread and nuts.
12 to 15 of 2.5mm 316L Stainless electrodes
Mate to weld with them
Two or three hours of time


Leave a gap of 1mm for tacking.

Go on then !No excuses, get into it!
Grahame

DJ’s Timber
29th Oct 2007, 08:28 PM
Guys, take note of the date :doh:. Think the job has probably been finished by now :U

neksmerj
30th Oct 2007, 12:22 AM
A last thought,

If your balustrade consists of a substantial top rail, and end posts, and you wish to fill in the height with a some form of safety barrier, consider using stranded 3mm s/s cable with turnbuckles at each end. The ends of each cable are turned back on themselves, then crimped, to form a loop.

Each turnbuckle is attached to the post, then connected to the ends of the cables. A bit of tightening, and wallah, jobs done. This is the architects delight, trust me.

Ken

Fossil
30th Oct 2007, 04:37 PM
Guys, take note of the date :doh:. Think the job has probably been finished by now :U

Well I don't know that I agree.

I was going through the "to do" list on the weekend, and I have two or three jobs not done from 1998. :)

JTonks
30th Oct 2007, 11:47 PM
Pickling paste will remove any discolouring but wear gloves and glasses. You can get it from BOC.

Safety note re pickling paste.

The pickling pastes I am familar with contain hydrofluoric acid. This is probably one of the most dangerous acids to deal with as it migrates into your bones and attacks bone strength.

Can't emphasis enough the need for protective clothing

John