Holding small items

Hi,

The photo below is a part-made forked end for the S50 I'm building. I need to cut the slot for the eccentric rod in the square end. I'll probably hold it in the bench vice and use hacksaw and file but I was wondering how you would do it. I thought about holding the round end in a collet block and using a slitting saw but thought the clamping might not be good enough. Any suggestions welcomed.

Gary

Hi Gary,

I'm afraid that I might have done the work in a different order and machined the fork before I parted the piece off from the main stock. However, you are where you are. Either start over or make up two small brass clamping pieces and hold the work piece between them. Then saw the whole lot (clamps included) - they will be sacrificial.

It's something you learn the hard (e.g. expensive way) but it's always best to try and think through all the required operations before you start doing anything - something I will admit I am yet to completely master!

Regards,

IanT

I second Ian's opinion about doing parts like this while still on the end of the bar, with the last op being to part it off,complete.

However there are a couple of things you can do now.

If the 7BA thread is tapped already, you could make a 3/16 dia mandrel with a stub of 7 BA thread on it, Thread that into the part and hold the whole thing in a 4 jaw chuck or a vise, gripping both the mandrel and a bit of the unslotted square, while you cut the slot and file it or mill it.

Or you could make a brass rod end with a hole a thou or two larger than the 11/64 stub and soft solder the part into it temporarily to make a bigger handle to grip the part in a vise for cutting or milling the slot. The slot can then machined. and the solder melted to separate the finished part from the rod, and excess solder wiped away.

Good luck, JD

As the others have said work on the end of a longer bar but I suspect that as this is a Stuart kit they did not give you much extra stock to play with in which case you could have drilled for the pin, cut the slot and then inserted a packer so the fork did not collapse while held in the 4-jaw to turn and thread the end.

J

One of the advantages of reading ME articles on eg Loco construction that some on here moan is so boring and blah blah they won't subscribe any more, yes the advantage is you pick up ideas for this kind of thing and store it away in your brain for use ten years down the line.

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As per Jeff's recommendation ... but I would use either Shellac, or Wood's Metal

... a bit easier to handle, and to clean off, than Solder.

MichaelG.

Thanks for the suggestions chaps. For this project I have been following a Tubal Cain article published in ME Aug 92 to May 93. His instructions were for someone who only had a lathe and for this part he suggested mounting on a vertical slide and using a 3/32 slot drill. With hindsight, it may have been easier to mill the slot first then part off last. I could have then tapped the hole afterwards. As Jason says you don't get much to play with in Stuart kits (about 5/8" in this case) but obviously that doesn't stop me using another bit of brass bar. Jeff's mandrel idea sounds appealing if the vice won't hold it well enough. I've got some 7BA screws so I could just fasten it to a short piece of 3/16" bar as suggested which would give extra support.

Bazyle, my problem would then be finding it again in my brain.

As I said above I'll try holding it in the bench vice first and sawing and filing it but thanks for the ideas. I'll let you know how I get on.

Gary

Hi Gary

I have just made 16 fork ends the same as you need to do. Mine were from quarter inch square steel.

I Completed mine ( Rightly or wrongly ) as you suggested.

The parts were made unto the stage you have now and then they were held in the collet block and the fork done with a slitting saw on the mill. Although this is the first time I have made forked ends and also used a slitting saw I had no problems and all came out spot on. Even the extra, Just incase I cock up ones came out well.

If I had to make more I would probably do them the same way to be honest.

Like I say I'm no toolmaker but it worked for me so that'll do.

Good luck

Dave

Hello Gary,

I don't think you have much to lose by glueing it into a hole in perspex or tufnol, whatever you have, using a modern foaming polyurethane adhesive and leaving it over gentle heat overnight. It will give you a handle to grip and it works very well holding short ends on wooden handles for sawing in a bandsaw.

I recommend Everbuild Gater glue. If you are canny you can preshape the 'handle' to give you support underneath it to help resist slitting saw forces. Take it gently though.

It will clean up nicely afterwards too, just run the tap through to restore the 7BA hole.

Good luck

Brian

You could soft solder it into the end of a drilled bar. Colin

Gary,

A slightly more sophisticated version of my earlier (clamping) suggestion would be to drill and tap two square bars and make a very small toolmakers clamp - assuming you don't already have a small one. Just make sure the clamp will lie flat by drilling the clamping holes in line.

A spot of superglue on the jaw tips will help stop the work from twisting and the small clamp (if held correctly) would be re-usable in that you could saw between the jaws without damage to them. Extra time to make but it might "come in handy" again sometime.

However, if you don't mind soldering the piece - I thought Jeff's suggestion was a good/quick one.

Regards,

IanT.

**LINK**

I have about 6 or 8 of these for small repetition work. they are one of those tools that if you gave them to 6 people they would all use them differently. I use them for holding small parts like the one the OP has posted, stops on jaws, stops on parts.

They are one of those things you wonder how you managed before.

"One of the advantages of reading ME articles on eg Loco construction that some on here moan is so boring and blah blah they won't subscribe any more, yes the advantage is you pick up ideas for this kind of thing and store it away in your brain for use ten years down the line."

What would be even better would be if the article was about solving this problem and the loco bit was left out entirely.Far more chance of remembering the technique then.

Edited By Carl Wilson 4 on 01/02/2014 21:04:18

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I suppose they could have another magazine ...maybe call it MEW

MichaelG.

hi gary,

i agree with IanT, but always pretty useless to be 'wise' after the event. Cherry Hinds/Hill made all her intricate bits by machining the bits on material then cutting off afterwards - a lesson well learned for your future parts!

yep junior hacksaw and file job in my book! probably just a few minutes work so good luck!

cheers,

julian

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I suppose they could have another magazine ...maybe call it MEW>>

They do, and it doesn't.

Edited By Carl Wilson 4 on 02/02/2014 08:50:37

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Sorry, Carl ... A wasted attempt at sarcasm on my part.

I thought that was what the stupid winky smiley thing was meant to denote.

MichaelG.

Having completed my EW slitting saw - I was anxious to test it and cut off Qty8 x 20mm lengths of brass angle for one of my modelling projects. It all worked well - nice clean cuts (no cleaning up) and very little wastage - & I was a Happy Bunny!

This morning I've realised that some of the next machining operations would have been much easier if the parts were still attached to the parent metal.

As I said Gary - I've not completely mastered this myself yet.

Regards,

IanT

Well here is the result. It fits and seems to do the job, but it's not pretty. In the end I adapted Jeff's idea and drilled a piece of 3/16 bar with 7BA clearance so I could use a 7BA screw to hold it, which made working with it much easier. Slot still ended up rounded even with a flat needle file. If I decide to make another I'll try slitting it before the turning operations and while still on the stock. Might be a good learning exercise anyway as it's only a small part. I didn't fancy soldering or gluing as I thought it might take me longer to get it clean afterwards.

John S - I thought I knew the Arc catalogue inside out but hadn't spotted these small clamps. Worth having some at the price (that should get you your £2 back).

Again thanks for all the suggestions, even though I didn't use some of them they are stored away for the future.

Gary