Enlarging Hole

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Absolutely, Rod

I forgot to mention that.

MichaelG.

Seems like flap wheel in an electric drill might be good enough?  Or a cylinder hone?

Edited By not done it yet on 23/12/2017 23:41:41

Or if you don't want to make a boring bar then what about a 1" blacksmiths drill in the drill press, would depend a bit on what speed the drill will come down two.

When you say a watchmaker's lathe, how small is it?

Is it possible to clamp the block to the cross slide and use a tool held in a chuck to bore it out?

If you mount the block upside down you will only need about 1" clearance over the cross slide.

.

If it's a traditional watchmaker's lathe, they usually don't have slides

MichaelG.

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Edit: This spare 'WW' style headstock is from Steve's Album:

http://www.model-engineer.co.uk/sites/7/images/member_albums/163849/724452.jpg

P.S. In his first ever post, Steve mentioned: "I've got an ancient belt driven "Champion No1" pillar drill."

Edited By Michael Gilligan on 24/12/2017 10:45:55

Hi Neil, fair point but there is far more information available about you in the public domain--voting list, council rating list etc etc -- unless of course you live in tent ! Merry Christmas !

Given a location, there will be lots of folk on here who would be happy to help, as already evidenced.

I'm in Cambridgeshire, if that's any help.

If you are near to anyone who has offered help and given their location, send them a P M.

Howard

Firstly, thanks for the suggestions and the kind offers of help.

Secondly, I’m not “trying to hide”. I’m just quite new to this forum and didn’t even realize I could set a location! I’m in North London, not far from Ally Pally.

The clamp fit to the 1 inch bar has to be good as I will be adjusting and moving it a lot. I’ve tried files, abrasives and flap wheels on previous clamps and it seems impossible achieve a good parallel hole that grips on its entire surface. It’s slow tedious work as well.

My Lathe is an 8mm with no cross slide and my drill has a capacity of 1/4 inch so machining is out of the question.

I hope this clarifies what I actually need and the limits of my workshop.

Any more suggestion would be most welcome.

Cheers

Steve

Hello Steve,

If precision is needed then I think you need help from someone with bigger machinery than yours. Living where you do gives you a big reservoir to appeal to..

Brian

Steve,

I don't want to labour this, but ... boring on the drilling machine [as I suggested, and Rod endorsed] seems an entirely reasonable approach.

MichaelG.

Thank you Michael but I'm finding it hard to visualize the set up you described. Perhaps you could clarify a little or post a sketch?

I would like to do this myself and your method sounds intriguing.

Cheers

Steve

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Steve,

Your junk box may differ from mine, but; what I would do is take a long 5/16" caphead screw and cut off the threaded portion leaving the plain shank and the head.

Cross-drill the head 1/8" diameter, and insert the shank of a broken HSS drill or milling cutter ... fix this by silver soldering, or with Loctite 638.

Grind the inserted bit to make a single point cutter which sweeps a 1/2" radius at the tip

... remember to check the actual diameter of the screw shank and measure accordingly.

This is your boring bar.

Centre the 25mm hole on the drill axis and clamp it in place [with suitable packing/spacers]

Then just operate the drilling machine normally.

I hope that makes sense ... Domestic duties are calling

MichaelG.

This is the sort of thing Michael is describing. As you only have 1/4" drill capacity you may need to come down to an M6 or 1/4" cap head bolt or could reduce part of an 8mm or 10mm bar down to 6mm in your lathe. If you make from bar then set the cross hole up from the end a bit more and drill and tap for a grub screw to hold the cutter then it is more easily adjusted.

Well done, Jason

Thanks

MichaelG.

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Sorry, I didn't check the capacity of the Champion No.1 

http://www.lathes.co.uk/champion-drill/

Edited By Michael Gilligan on 24/12/2017 17:43:58

Most ingenious thinking Michael; JS would have been proud of that

Brian

I don't think the bearing on a normal drilling machine wil be good enough for that method to work.

Les.

I have used a similar boring bar with no problem just needs a guide nose to locate bar.

Use plenty of lubrication and run slowly with job clamped well.

David

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Sorry, Les ... I don't know what constitutes a 'normal drilling machine' so I can't really comment.

But, in Steve's situation I would certainly give it a try.

MichaelG.

Few pics of the type of bar being suggested in a normal drill press about half way down this page.

A tool makers reamer could be made up, wouldn't even need to be hardened for aluminium. Cut the slope on the cutting edge at about 20*, +-, it doesn't really matter.

Ian S C

Edited By Ian S C on 26/12/2017 09:52:14