Shortening BA screws

[AStroudParticipant @astroud]

I would be interested in members’ hints and tips for shortening BA screws/creating BA studs.

I have about 40 6BA x 0.5 ” long studs to make, made either from a length of studding or by cutting lengths from long 6BA screws. I would normally use a cut off disc in a dremel but this seems to use up the wheel quickly, leaves a ragged cut off end and the bit being too hot to hold can disappear into the nethers. Doing this manually it is also difficult to get repeatable lengths

I am purchasing some of the 1mm THK cut off discs possibly to run in the lathe and then present the studding to it screwed into a simple jig to set the length needed.

Or should I be using a junior hacksaw?

Andrew

 

 

[Harry WilkesParticipant @harrywilkes58467]

have you considered using a parting off tool ?

H

[JasonBModerator @jasonb]

I would saw them off. At 6BA it’s a toss up between junior hack saw or piercing saw for me. Then into the lathe and use a file on the end while rotating to put a neat concave end on it.

[bernard towersParticipant @bernardtowers37738]

Playing around with small ba screws/studs requires some dedicated tools /jigs one of which is the lantern chuck which will repay you many times over for a wet days work. Small parallel shaft ER collet chucks come into their own for jobs like this especially ER8 size. You will find things a lot easier with the turning and parting if spindle speeds are increased quite dramatically. I have a little Peatol lathe which has a top spindle speed of 9000rpm, this makes the machine bit of the job a doddle. Best of luck.

[SillyOldDufferModerator @sillyoldduffer]

I find it helps to put a nut on the thread below the saw point.  After filing the end flat, remove the nut by running it off over the flattened cut end to remove burrs.  A spanner may be needed.

I find tidying up with an ordinary nut put on before sawing and filing quicker than deburring with a die.

Don’t expect the nut to last forever.  Consider the nuts sacrificial because deburring gradually damages their threads.

Dave

[duncan webster 1Participant @duncanwebster1]

If you’ve not got too many (whether 40 is too many is up to you), then a bit of say 5mm flat with a 6 ba hole near one end, then a sawcut through the hole and continuing a fair way beyond will help you nip the stud/bolt in your vice for cutting/filing. I keep meaning to do something better as shortening bolts is really boring

[BazyleParticipant @bazyle]

Drill a hole a tad over size in a bit of 1/4″ round and depth equal to length required less the full steel nut mentioned by SOD above. Hold in lathe tailstock chuck.
Hold studding in 3jaw or collet with two nuts on the exposed end for deburring as mentioned above. Insert exposed thread into hole in 1/4″ bar leaving small gap between the two nuts. Cut with hacksaw between nuts.

The lathe is only being used as a holding jig and the bar with hole stops the cut off end being lost.

[Speedy Builder5Participant @speedybuilder5]

I use these crimping pliers which can shear a selection of small metric threads. They will shear off 6BA studding easily enough, then clean up the sheared face with a file in the lathe.

[JasonBModerator @jasonb]

No wonder people think I get a lot done, all this faffing about to cut some stud/screw shanks and little mention of tidying the end once it is cut. I’ll regularly do 40+ for an engine in very little time and that includes threading the bar to start with.

[JasonB]

On JasonB Said:

I would saw them off. At 6BA it’s a toss up between junior hack saw or piercing saw for me. Then into the lathe and use a file on the end while rotating to put a neat concave end on it.

+1  though I think you mean convex not concave.

Mike

[Speedy Builder5]

On Speedy Builder5 Said:

I use these crimping pliers which can shear a selection of small metric threads. They will shear off 6BA studding easily enough […]

sounds a bit risky ^^^ aren’t the shearing locations tapped for specific thread sizes ?

… a vintage model would hopefully include 6BA

MichaelG.

[Martin KyteParticipant @martinkyte99762]

I use a piercing saw a lot for this job. Lantern chucks if you are being fussy.
It’s also possible to make your own cropping tool. Couple of circles of gauge plate with extensions for handles. Device clamped through the middle of the circular bit with a nut and bolt. Drill and tap a circle of BA (or whatever) holes for all the sizes you use. Separate and open up one of the pair to clearance size. Harden and temper.
You can then screw in your bolt to depth and operate the tool by squeezing the handles. Crops cleanly enough to use the bolt without further work.

regards Martin

[noel shelleyParticipant @noelshelley55608]

I have used the crimping/cutting pliers shown by speedy on small screws in electrical work, they worked  BUT I felt a better pair could be made from silver steel or gauge plate – never got round to it ! Noel.

[JasonBModerator @jasonb]

What mor edo you need?

Bit of 7BA studding I’ve had laying about for years. Held in small vice and sawn with piercing saw, length to rule. Into the lathe and a few strokes of a file while twisting it in your hand and job is done. Nice domed (convex) end and no burrs

Seems to work Ok

[AStroudParticipant @astroud]

Thanks, some ideas to take away. It seems keep it simple and be patient works.

Andrew

[Adrian R2Participant @adrianr2]

I recall Myford Boy making a load of meccano screws from threaded rod on his lathe – oversize nut held in chuck to feed the rod through, second nut as a jam to hold it at length, feed out to a stop and part off, looked very neat and quick. He also cut slots (slits?) in the heads with a slitting saw.  There’s a video on Youtube if you search.

[JasonB]

On JasonB Said:

What mor edo you need?

Proper studs rather than lengths of studding? Grin!

Andrew

NB: What happened to smileys?

[JasonBModerator @jasonb]

As I said earlier I would usually thread my own but as the OP was intending to use studs or cut the heads off screws that is what I went with😊

Well actually on such small studs that are often holding things that are no thicker than 1 x their diameter it is hardly worth leaving an unthreaded section in the middle that may only be 2mm or less long, at least that is what I tend to do. If it were say a stud for a valve chest and cover then not worth the time threading the whole length.

But just for Andrew 😍

[SillyOldDufferModerator @sillyoldduffer]

Jason’s given me something new to try, that is simply chopping stud to length with a saw, and then rounding burrs off in a lathe with a file.

Until now, I’ve always added a nut, chopped with a saw, filed the end flat in a vice, and then de-burred with the nut.   If it works, and Jason is always credible, then his workflow should be faster, not least because it eliminates fiddling with a nut.

Dave

[JasonBModerator @jasonb]

Although the nut method will break off a burr it can still leave a sharp corner. The doming by filing method will remove any sharp edges and the file size should be adjusted as the stud gets larger, for something like M10 then a 10″ lathe file would get the job done a lot quicker than that small file I used in the video.

If it is more of a functional item rather than a steam engine that should look nice then a larger stud can always be faced and if positioned correctly the same tool used to cut a chamfer on the corner

Usual warning when filing on the lathe, use a handle, roll up sleeves and if you have one use a collet chuck as they don’t hurt as much as a chuck jaw. If you want to be really safe hold the file backwards and offer it up to the underside of the work.

[JasonB]

On JasonB Said:

 

Usual warning when filing on the lathe, use a handle, roll up sleeves and if you have one use a collet chuck as they don’t hurt as much as a chuck jaw. If you want to be really safe hold the file backwards and offer it up to the underside of the work.

That seems really awkward, when you could just act like you’re lefthanded. Not something I’d want to do for a real filing job, but a few strokes at a time isn’t a problem

[JasonBModerator @jasonb]

Not the same as acting left handed.

The option I describe will draw the file away from you should it get hit by a chuck jaw or part of the work as it is in contact with the parts that are rotating AWAY from you.

Left or right handed with the file on the top of the work which is rotating TOWARDS you if the file hits something it will get pushed back towards you hence why a handle should be used as that is better than having the tang pushed into the palm of your hand.

 

[Howard LewisParticipant @howardlewis46836]

For just a few screws, in 6BA a Junior hacksaw and careful cleaning up of the end with a file, will do quite nicely.

If you think that you may have to shorten a lot of other screws, in the future, consider making a John Ashton Screw Modification Fixture.

(He won the John Stevenson Memorial Cup a few years ago for it)

The time making it will be well spent! I have a box with about a dozen holders for threads from 8-32 UNC up to M8. Saves me a lot of time and allows screws to be shortened, chamfered or domed quite neatly.

Howard

[JasonBModerator @jasonb]

The OP only wants to use the threaded shank of the screws as studs, so no need for fancy jigs or tooling.

[Howard Lewis]

1. On Howard Lewis Said:

   For just a few screws, in 6BA a Junior hacksaw and careful cleaning up of the end with a file, will do quite nicely.

   If you think that you may have to shorten a lot of other screws, in the future, consider making a John Ashton Screw Modification Fixture.

   (He won the John Stevenson Memorial Cup a few years ago for it)

   The time making it will be well spent! I have a box with about a dozen holders for threads from 8-32 UNC up to M8. Saves me a lot of time and allows screws to be shortened, chamfered or domed quite neatly.

   Howard

   Which issue? I’ve had to shorten over 100 screws on my latest project, time for something quicker or less tedious.

[Author]

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