Help need with Drill jig

[Alan CrookesParticipant @alancrookes88316]

Hi Everyone,

I dont know if this the right place to ask, but im after a little help creating a Drill jig for a project im going to be doing. I dont have the experience or tools to do this myself. I have made some 3d models with measurements of whats needed. But im not sure whats the best way to make it? Am i best making it layers, or from a single peice CNC'ed? Material, is metal best, or a softer material and drill bushes fitted? I'll attach the pictures so you can get a better idea of what im trying to do. If someone could help me make it, or knows someone that can, ill be very greatful! Payment would of course be sorted. The Hole size for the drill peice is 2.5mm.

Thanks, and i look forward to your advice.

Alan

[Alan CrookesParticipant @alancrookes88316]

[David LittlewoodParticipant @davidlittlewood51847]

Alan,

It would help if you told us what you are trying to make, what are you making it from (i.e. the material) and (equally important) how many items. How precise do they need to be?

The "how many" question will guide the decision about durability of the jig (hard bushes etc) – or even whether you need a jig at all: if you just want a few, then coordinate drilling using a DRO could be the best route.

Also, what part of the country do you live in – if someone is going to help you, face-to-face would be best.

David

Edited By David Littlewood on 24/11/2012 13:13:57

[Grizzly bearParticipant @grizzlybear]

Looks like polystyrene to me. As David said, more info. required.

Regards Bear..

[SiddleyParticipant @siddley]

If it was me I'd probably make that in sandwich form using gauge plate. Not the cheapest route, but possibly the easiest.

[Grizzly bearParticipant @grizzlybear]

Hi Siddley,

"If it was me I'd probably make that in sandwich form using gauge plate. Not the cheapest route, but possibly the easiest."

Any chance of borrowing your crystal ball?

Maybe I need some new specs.

Regards Bear..

[Alan CrookesParticipant @alancrookes88316]

Hi all,

thanks for the responses.

im looking to use the jig to drill holes in over 100 plastic pieces. The pieces will create a tapered box. The holes on the top of the jig are set at a 5 degree angle. There are holes on the side of the jig that enable the ends to align to the angle.

I'm ideally after someone that can fabricate this for me. It needs a level of accuracy I can't achieve, as all the pieces made in the jig will be interchangeable with each other to make varying sizes of boxes.

If the jig has bushes inserted into it, can a softer material be used for the frame?

any more questions, please ask.

[Alan CrookesParticipant @alancrookes88316]

Double post

Edited By Alan Crookes on 24/11/2012 15:00:25

[SiddleyParticipant @siddley]

Posted by Grizzly bear on 24/11/2012 14:29:29:

Hi Siddley,

Any chance of borrowing your crystal ball?

Maybe I need some new specs.

Regards Bear.

Be my guest, – it only usually shows videos of girls in string bikinis firing full auto machineguns set a rock soundtrack though – I'm not sure how that will help you

Seriously, I can't see what's missing from the drawing ? gauge plate is hard enough for most drilling jigs without heat treatment and it's easy to use. I can't see what relevance the part being drilled has ?

[SiddleyParticipant @siddley]

Posted by Alan Crookes on 24/11/2012 14:59:00:

Hi all,

thanks for the responses.

The holes on the top of the jig are set at a 5 degree angle.

I'm ideally after someone that can fabricate this for me.

Now he tells us about the 5 degree angle
I'll bow out of this discussion now as I can't realistically make the jig for you – not with me living in Spain. I thought you might want to make it yourself.

Good luck with your project anyway Alan !

[Alan CrookesParticipant @alancrookes88316]

The 5 degree angle isn't on the drilling, I just mean the line of holes are on a line 5 degrees off the right angle. The picture from the top down view should show this.

Regards,

Alan

[David LittlewoodParticipant @davidlittlewood51847]

Alan,

OK, I get it. Yes, I see a jig would be necessary. I also agree that gauge plate would be the ideal material. If I were making it though, I wouldn't use a hockey stick shaped spacer; I'd use a simple rectangular piece with a separate end stop. I would dowel and fit the parts together with cap screws (counterbored to sink them below the surface), then make the holes with the jig assembled, using co-ordinate drilling from a reference edge.

So, you need to find someone who has a milling machine with a DRO – a bench drill would be possible but there would be too much marking out and increased risk of errors. I suggest you take a piece of the plastic to be drilled, to make sure it will fit neatly in the jig.

I haven't grasped what the extra little bit is supposed to do – presumably some kind of packing to hold the plastic in the jig, but perhaps you could clarify.

You didn't answer the last question I asked – where are you based? – as you are far more likely to get help from someone just down the road than someone 800 miles away.

David

Edited By David Littlewood on 24/11/2012 15:57:57

[Alan CrookesParticipant @alancrookes88316]

Hi David,

Thanks for the In depth reply.

dont suppose you know anyone with a milling machine with a DRO?

the extra piece is a spacer, as I have 2 sized heights for the box, 100mm and 150mm. The spacer just ensures the first hole is in the right location.

I'm located at nottingham, just near Mansfield.

regards,

Alan

[SiddleyParticipant @siddley]

Posted by Alan Crookes on 24/11/2012 16:11:57:

I'm located at nottingham, just near Mansfield.

regards,

Alan

Blimey, about 10 miles from where I used to live – with my DRO equipped milling machine

Cromwell Tools at Mansfield will sell you the gauge plate ( AKA precision ground flat stock )

There is a custom bike shop, name of Izaax, in a village called Blackwell – which isn't a huge distance from you, just the other side of M1 J28. The machining guy there is pretty good, he'd probably make the jig for you and not charge the earth.

[Stephen BensonParticipant @stephenbenson75261]

I would forget guage plate and go for hardened drill bushes either commercial ones or ones made from hardened silver steel.

[Alan CrookesParticipant @alancrookes88316]

I found these a while ago, but couldn't figure out what size I would need for a 2.5mm bore hole, and what size the hole in the jig would be needed to fit them in.

**LINK**

with these, could I use a softer material? It says composite on there site.

[Stephen BensonParticipant @stephenbenson75261]

Posted by Alan Crookes on 24/11/2012 17:56:43:

I found these a while ago, but couldn't figure out what size I would need for a 2.5mm bore hole, and what size the hole in the jig would be needed to fit them in.

**LINK**

with these, could I use a softer material? It says composite on there site.

No you need a bush tophat shaped that you can loctite into ally or M/S

[David LittlewoodParticipant @davidlittlewood51847]

Alan,

The reason why several of us have suggested gauge plate is partly because it is hard enough to stand up to a fair amount of wear, even without being hardened – but mainly because it is dimensionally very accurate. Most metal sections of a more mundane pedigree are often not too close – mild steel, for example, is often a couple of thou undersized, and also can be not as crisp in its cross-section. The only way to get it spot on is to start with a larger section and mill it down to size – and then (with bright sections) you can run into problems with distortion if you don't stress relieve it first. Black MS is rather better in this regard.

Of course, one thing for you to check is how precise is the section of your plastic. If that is slightly under nominal size, then you might find MS or aluminium in commercially available sections would be OK. MS would probably survive a few hundred holes without hardened bushes, if you are careful; aluminium probably wouldn't.

I have a miiling machine with DRO, but I'm too far away from you; I really think you need someone close so you can get together 2-3 times to get everthing checked out.

One afterthought – you might like to consider adding a metal section – say 6 mm square – at the base of the jig so that you can hold it in a machine vice without obscuring the holes or the slot for the plastic sections. As designed, you may have trouble in that respect.

David

Edited By David Littlewood on 24/11/2012 19:16:02

[Ian S CParticipant @iansc]

You could proberbly get away with MDF with mild steel bushes, or just hot rolled mild steel. You could make it from 7075 T651 Tooling Plate (it's as tough as steel), and use hardened bushes, that will see you right for a production run of a few thousand, then you replace the bushes. Ian S C

[Stephen BensonParticipant @stephenbenson75261]

I not sure any of you have ever designed or made any tooling jigs, I was taught by an old time toolmaker running a production engineering company means I have used, made and designed many jigs over the years.

[John Stevenson 1Participant @johnstevenson1]

Alam.

PM sent, check your messages.

[Robert DoddsParticipant @robertdodds43397]

Alan,

Little has been said so far about how your plastic bits fit together and interact with each other.

Are you using pins to fit in the respective holes? Is it fastened with screws, self tap or otherwise?

How many holes in each member wil be populated? All this has a bearing on the accuracy of positioning of the holes in the plastic and likewise on the type of jig you require.

Note that those press fit serrated bushes you highlighted are only to 0.003" concentricity so you're off to a poor start there if you a looking to use close fitting pins in the assembly.

As for jig design there will be many ways of constructing but I would consider locating the parts against dowel pins (2 on one edge and 1on the end) as this will enable swarf from your drilling to be kept clear of the register faces and minimise the chance of swarf accidentallly mis-locating your parts and subsequent holes. At 100 off it matters little whether you go MS and hard bushes or gauge plate but I would try and incorporate a toggle clamp to keep your part in register whilst all the holes are being drilled

Bob D

[John Stevenson 1Participant @johnstevenson1]

Posted by Robert Dodds on 25/11/2012 12:38:40:

Note that those press fit serrated bushes you highlighted are only to 0.003" concentricity so you're off to a poor start there if you a looking to use close fitting pins in the assembly.

Bob D

.

0.003mm so 0.0001181 " [ approx] which is probably a tad better than the average bench drill or POS Bridgeport.

John S.

[Robert DoddsParticipant @robertdodds43397]

John S,

Sorry mate , Go and read the PDF file for those parts B&T are so long established they still have imperial sizes.

I tried to copy the page to you but its a bit to big for this system

**LINK**

They are for use in plastic jigs and composite materials rather than "real "engineering materials

Bob D

[Donald WittmannParticipant @donaldwittmann92536]

Gauge plate would be about the best for your needs, also no need to harden it.

Ah yes 3 microns, a tad better than a Bridgeport, agreed, but also about 30 times better than anything Mr Chinaman can produce.

Donald.

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