Need help locating bolt

Hi everyone,

I realise this is perhaps not the best place to ask, seeing as my project is not a model, but this forum keeps coming up in my searches for answers to various engineering questions, and I haven't been able to find a better UK based forum for this type of question. Apologies beforehand if I'm out of order!

I recently bought an old Gestetner paper guillotine with the intention of restoring it to working order. It's a beautifully made cast iron piece of the highest quality and seems well worth the effort. After disassembly I noticed that the main bolt which attaches the guillotine blade to the body, and upon which the blade swivels, is pretty badly worn and could do with being replaced. So I started looking around for a UK source for good quality bolts but only ended up confused and disappointed; most of what I can find are very low quality zinc plated bolts, poorly finished and probably not very wear resistant - nothing like the nice old one I need to replace. It seems cheap Chinese junk has taken over also the fastener market The bolt is a 1/2" diameter, with a 1" threaded section, probably UNC, possibly BSW(?). Since it acts as the hinge for the blade it needs to have a smooth shoulder (also 1/2" dia) and be made from some wear resistant alloy. Here are a few photos:

Does anyone here know where I might find such a beast?

Hi Mr bent spanner,

try www.essex fasteners .......they carry a lot of weird stuff..... but it's the quality thats ur problem but u could use an "unbreako" socket head screw they are High tensile 12.9 quality, I think, they are not zinc coated but proper old fashioned bolt....u may will get the shouldered bolt but u may need to get the thread made a little longer....

(ie shoulder to long) just phone them they are very knowledgeable... and they will explain the dimensions of what they have or get for u over the phone.....

also they post.....I must say I am only a customer and have nothing else to do with them.....

there is a manufacture of specials (bolts) in Bolton - lancs, they made some bolts for an antique steam engine I had.......

where I worked there was a place (Birmingham) that used to make bolts that were 1 1/2" dia x 36" long and x rayed ...not cheap but anything is possible....

you should say where u are......poss. someone on the forum may help u....

I live in France now and it was a long time ago I had job's like these done, if ur not successful in your search

let me know and I'll go thru my old address books for u.....

get lucky Frank

Raking around in my box of odd nuts and bolts I've found a 1/2" whit bolt and nut. Overall length including head is 2.4", threaded portion is 1.1" and unthreaded shoulder is 0.95" long x 0.495" dia. Spanner size 7/16 whit. It's not new but in good condition and would do the job if you can't get a new one. Let me know if it's any use.

Edited By Roger Provins 2 on 15/11/2014 18:04:50

Hi Bent Spanner, my guess is that the bolt will be either BSW or BSF and it looks to be a standard bolt rather than a set screw. Set screws have the thread up to the head and bolts have a plain section. Gestetner were in business in the UK during the last century so pretty sure to be a UK thread ?

It would be best to use a thread TPI gauge to ascertain the pitch and measure the A/F of the hexagon, if it is. a standard bolt any good engineering supply house should be able to supply what you need.

If you are really stuck PM me.

@Frank: Many thanks, found Essex Fasteners at Orbital HS - apparently they've merged. There is no on-line product list (or shopping) but there is a PDF which at least shows the ranges they carry. You were indeed right to say "they carry a lot of weird stuff" - they seem to have almost every type of fastener under the sun! I shall contact them on Monday and see what they say.

@Roger: That's a very kind offer, thank you! It sounds like the bolt you found is very nearly a perfect match to what I'm looking for, it's only the shoulder that sounds like it could be a problem (see also below); on the one I have the shoulder is a tiny fraction over 1/2". I confess I don't understand the Imperial vernier on my calipers (I was born metric!) but an exact measurement is 12.8mm (or 0.504 inches) - it's likely that 0.495" would leave enough of a gap that the blade will wobble, doubly so since I'm measuring a worn bolt! I'll certainly keep your offer in mind though!

@John: Ah yes, I should have made my uncertainty about the threading clearer; I at first counted 13 threads / inch and assumed it was a UNC thread, but checking again it's actually only 12, which matches BSW. This also makes sense as, hidden between two screwed together parts, I found a "Made in England" stamp I should get a set of gauges really; this isn't the first time I've been confused over a thread! Thanks for your suggestions, and for pointing me in the right direction, thread wise.

Edited By Bent Spanner on 15/11/2014 23:27:42

Edited By Bent Spanner on 15/11/2014 23:28:03

I had a check on Google, there is a supplier of parts there, there seems to be a mixture of threads !/2" 13 tpi (unc), 1/2" 12 tpi BSW, or some are 12 mm no thread size quoted so probably course. I would say that is a 1/2" BSW bolt, get either a standard un plated (black) hex head bolt, or a socket head bolt.

Ian S C

Hi bent spanner,
Even replacing the bolt may not correct your wear problems as the hole and in the lever arm may be worn also and may need to be machined and have a bush fitted.
Best of luck.
Peter.

Edited By Peter Tucker on 16/11/2014 18:25:43

Hi Peter,

There is a little bit of play with the existing bolt, but I'm not equipped to enlarge the hole; even if I trusted my fairly basic drill & stand to produce a perfectly round hole (which it won't!), my drill only chucks up to 13mm, which would leave only 0.3mm for a bushing. So unless I can find a 1/2" bolt with a machined 0.508" shoulder (measured hole dia) then one that is exactly 1/2" is going to have to do. I am assuming that this will be easier to find. For what it's worth, the inside surface looks fine, and the sleeve is 1" long, so a bit of play is acceptable (blade angle is the important factor here, vertical precision is almost irrelevant). Bear in mind also that this is a hand operated machine with no gearing; the joint will only move slowly and very infrequently.

Edited By Bent Spanner on 17/11/2014 22:26:03

You could get someone to make one if it was that critical.

A grade 8 bolt from any engineering supply shop should do the job.

Or if you search that well known online auction site for "1/2" grade 8 bolt" a veritable cornucopia will appear.

Edited By Hopper on 18/11/2014 08:25:49

Thanks to everyone for their input - I have now heard back from Essex Fasteners and they are unable to supply this bolt. I've also looked at that auction site, but a search for "1/2" (whichworth,bsw) bolt turns up nothing suitable. So unless anyone can suggest another possible source it looks like I'm going to have to find some way of reusing the existing bolt - or take up Roger's offer of a second-hand one. Today I received 1kg Oxalic Acid which will be used (not all of it!) to clean the surface rust from the blade, and the other parts have been cleaned and sanded, ready for spraying. That bolt will soon be the only thing standing in the way of completing the restoration!

Cromwell tools have 1/2" bsw bolts listed in both their on/line and paper catalogues. The on/line pricing shows price/100 but the "add to basket" button asks how many bolts you want and will accept an order for one - don't be too shocked at the price though.

You didn't say which part of the country you are in, but I'm surprised if a local "professional" bolt supplier can't come up with the goods. I'm in Chester and our local supplier keeps this sort of thing in stock ready to sell over the counter in ones or twos or however many you want. His reason - there are a lot of old machines with these threads still around.

I assume the above search term was a typo - not surprised if whichworth, bsw didn't get many Google hits Whitworth, bsw might be more successful.

Hi bentspanner, I have just had a rootle in my 1/2" BSW tin and found some bolts to your specification apart from the plain section diameter. All I have miked up come out at 2.5 to 3 thou down on the nominal 1/2" diameter. I would bet this is industry standard. I have some cap screws too, these are even less on the plain part. Could you make a shim steel sleeve to take up the slack, if any? It would be OK for hand operation surely.You are welcome to one, pm me with your details. Chris Gunn

Surely there has to be SOME play or it wouldn't be a free enough fit to work, and the big leaf spring does the job of keeping the blade aligned. Isn't the technique to hold the blade against the base when cutting anyway?

Neil

As an extreme solution you could build up the old bolt with weld and then r machine down to the size you want. Another solution is to turn down the damaged area and then make a split bush to go onto the straight bit this could be soft soldered and then turned true. Whilst machining the bolt, re face the inside of the bolt head until cleaned up and fit a washer.

Someone local might be able to do that for you if you don't have the kit.

Done a quick drawing for you if it's any help. Not dimensioned though.

Edited By Bodgit Fixit and Run on 19/11/2014 18:55:39

Seems a lot of aggro for what seems to be a simple 1/2" BSW bolt, the leaf spring is there to take up any slack on the blade so should keep the tension of the top blade against the bottom blade to effect the cutting action. Modern versions have a simple coil spring in the same location for the same purpose, & as been said you hold the top blade against the bottom as you cut.

George

The original bolt looks like brass or similar softish metal. It may be designed so that wear in this soft component prevents wear in the parts which pivot on the bolt. That would prevent a much more awkward (and potentially expensive) repair or replacement of those other parts. If it was me, I would replace the bolt with one of a similar material.

Marcus

.

Marcus,

I suspect that's just because the colour temperature of the lighting is "warm"

... compare the first image, which shows the bolt in-situ.

MichaelG.

Golly, thanks a bunch for all the interesting comments & suggestions - I knew this would be a good forum! I'll try to respond to each of the points made, but first I have to share these "before and after" photos of the guillotine blade:

Before:

After:

Pretty amazing, don't you think? That's after degreasing and soaking in oxalic acid for two hours (~400g oxalic acid ~5L warm water). It actually looks even better in real life; the bits of oxide left are not "rust" but black oxide, which oxalic acid won't remove (I seem to have a lot of colour balance problems with my photos!). I may try to buff these out, but I'm not too fussed. The other side of the blade looks even better, almost like new, and it still has a good edge despite being 50-odd years old. That said, if I wanted to sharpen the blade, does anyone have any suggestions how to go about it? Might be best to take it to a company that specialises in sharpening tools?

If you buff it up. do so before you have it sharpened as this could slightly dull the cutting edge by rounding it. There seems to be a problem with the drawing I uploaded, regarding repairing the bolt, earlier so I'm trying again now.