Benson Vernier Height Gauge

Hi to all model engineers in the UK. I have recently acquired a very nice Benson Vernier Height Gauge model no. H.E.M.10. It is missing two small screws that I would really like to replace to make the gauge useable. The main one is the thumb screw on the fine height adjustment. It is 3/32 48g whitworth thread according to my thread gauge, with a knurled knob on the outboard end. Does anyone have any idea where I might source such a screw ? I hope this is the right area for this post. Thanks.Regards. Ray

I think you will have to make one, may be worth trying a #3-48 UNC thread which would be easier to get a die for, fractionally larger at 0.099" but tighten the die a bit and it may get you by.

J

Ray, Check very carefully I think it is more likely to be 6 BA, 0.110" dia x 47.93 tpi I have never seen 3/32 BSF in 50 years of engineering -- it does exist but I think it is probably a non preferred size.

John

Thanks for the replies . Yes you are probably right John, I miked one of the existing screws which are the same size and it went 109 thou so 6 BA it is. I will search the internet again and see what I can come up with. Otherwise I will try and make one.

Regards

Ray

Ray,

I would suggest that you make [or find/modify] a knurled "head" to your taste: Drill & Tap 6 BA and insert a screw.

... Much easier than making in one piece.

MichaelG.

.

Note: Old electrical fittings are a great source of material.

Yes, I would back the thread being BA, (I think that I have come across a BA thread on a Benson Height Gauge).

If its a British made measuring instrument, of a few years ago, I would expect to find, BSW, BSF or BA threads, rather than UNC or UNF.

My immediate reaction was "Make one". You can have the head whatever size seems/feels/looks reasonable.

Obviously don't have a 1" knurled head on a 6BA, to prevent shearing it off, but 5/16 to 7/16 would seem suitable to me.

Howard

Thanks again for all the helpful replies. Once John identified the correct thread it was much easier sourcing a screw out here in the colonies. I will do as Michael suggests and make a knurled head and Loctite it to a screw etc. Problem solved.

Hi,

Have just checked my Benson VHG, and the screws on mine are 6BA. The knurled heads are 7/16" dia. and just under 3/16" thick.

Regards Barry

You can make a knurling tool to do a job like that in a few minutes work. First find a cigarette lighter, you need the wheel, then find a spindle, I use the rollers out of needle roller bearings, some of mine are 3/32", others 2.5 mm, then you have to make a bush to fit in the hole in the wheel. Next find a bit of scrap steel, cut a fork in the end, and cross drill it for the spindle, that's it, they are great for knurling small nuts etc., brass, steel, aluminium, keep plenty of oil on it to lub the spindle as well as the work. I'v had one for years, and it still goes well, I thought it might be lucky to do the job it was made fore. Reference to "Introducing The Lathe" by Stan Bray. Ian S C

Thanks Ian. What a nifty idea. Trashed the disposable lighter hiding in my sail repair bag and made a simple knurl based on your idea. I used a piece of drill rod for an axle. I have turned down a small piece of round stock , centre drilled and sized for 6BA tap, put a light knurl on with my home made tool and faced the button slightly convex as per the original and parted it off. Now waiting for my 6 BA tap to arrive. So far I am very happy with the way it is turning out. Undecided whether to loctite or solder the screw in before facing off the head This is the smallest thing I have made in my limited experience and a lot of fun. Thanks to all for the guidance.Ray.