Centre drill extension

I have a home made X Y table from part of a small mill on my bench drill which I use for coordinate drilling.
One problem is a limited quill travel of 50 mm and switching from a centre drill to a twist drill takes up nearly all the travel and moving the drill head loses the datums.
The answer is to make an extension for the centre drill to match the length of my edge finder and the length of the average twist drill. Made two for different sizes rather than a double ended one and rather than use grub screws I have simply used Threadlock which is easily removed with heat.
Attachment 22670
The bench drill has been modified to enable the head to be lowered on the column to within range of the job in hand.
Attachment 22671

That's a good idea. When I made my morse taper centre drill holders I really should have made them with a bit of an extension.

Have the same problem even with 84 mm quill travel which I have at drill/mill. Nice idea. Thanks for sharing.

Cheers
LMMasterMariner

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Interesting idea. I am really interested in how you modified the drill press to lower the head. Could you say a few words about that? I was thinking of modifying one of my little presses that way.

Quote:

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Originally Posted by JoeH

Interesting idea. I am really interested in how you modified the drill press to lower the head. Could you say a few words about that? I was thinking of modifying one of my little presses that way.

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Hi JoeH,
Very simple to do on my press as the only thing I needed modify was the belt guard by cutting away a portion to allow it to still flip for a speed change.
I have made a security column stop collar which is vital for a controlled decent and the column is now a solid one to replace the flimsy thin walled tube of the original.
There is little point in doing all this unless one is using an XY table which is why I have not posted the mods as everyone seems to have a mill these days.
Hope that helps.
I have replaced the clamping set screw for a bolt for easier access

Quote:

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Originally Posted by JoeH

Interesting idea. I am really interested in how you modified the drill press to lower the head. Could you say a few words about that? I was thinking of modifying one of my little presses that way.

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Hi JoeH,
Very simple to do on my press as the only thing I needed modify was the belt guard by cutting away a portion to allow it to still flip for a speed change.
I have made a security column stop collar which is vital for a controlled decent and the column is now a solid one to replace the flimsy thin walled tube of the original.
There is little point in doing all this unless one is using an XY table which is why I have not posted the mods as everyone seems to have a mill these days. I have replaced the clamping set screw for a bolt for easier access.Attachment 22728
Hope that helps

Thanks for the posting Olderdan. I like the idea of it for small shop presses with that issue. As I don't have an XY table (yet) I do try to minimize movement of the table height by finding a comfortable place for both and the throw before starting operations...but not always possible. Your idea would work great. One day I'd love to have a set of stub/screw machine drills that could be used on my mini or the press. I do keep any broken bits and resharpen if possible to more of a stub size...but still a far cry from a 115 piece set. Nice looking XY table too. Interesting design of your DP in that the post is pretty centered in the head/motor mount makes for even load as most inexpensive ones I've encountered seem a bit nose heavy and your solid post would make a world of difference.

I've seen mods for a side jack screw to raise and lower the head or a heavy table...if you move it a lot might be worth exploring?

Thanks again for sharing,
PJ

Quote:

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Originally Posted by olderdan

Hi JoeH,
Very simple to do on my press as the only thing I needed modify was the belt guard by cutting away a portion to allow it to still flip for a speed change.
I have made a security column stop collar which is vital for a controlled decent and the column is now a solid one to replace the flimsy thin walled tube of the original.
There is little point in doing all this unless one is using an XY table which is why I have not posted the mods as everyone seems to have a mill these days. I have replaced the clamping set screw for a bolt for easier access.Attachment 22728
Hope that helps

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Thanks. My purpose is a little bit strange. I want to lower the head so I can use it kind of like a mag drill without the magnet. Still thinking of ways to hold everything down.

Thanks PJs
The 14 x 4 inch mill table was from a Portmac Redman mill in the style of a mini jig borer made in the UK and the X axis was part of the base casting which I did not have, I would have loved to obtain the whole machine.
Attachment 22755
The slides are of square section so are made square to each other, I made an X axis from an alloy plate with brass bearing surfaces and various bits to form a slide, as this is only used for positioning it has proved up to the job.

Thanks Olderdan for the rabbit hole on that fine old iron bench machine. Lathes.co.uk had quite a write up on them. Quite a good size table for your press and would think your X axis being made from plate would keep the profile low. Do square section slides work as good as dovetails?

Thanks again. PJ

Quote:

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Originally Posted by PJs

Do square section slides work as good as dovetails?

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As you can see by this screenshot there are some high precision slides made this way and may in some circumstances are easier to make for the home workshop and many have been made by a built up construction and can be easier to refubish. L.C.Mason made a small screw cutting lathe by this method from gauge plate.
Its all down to what suits your application as which one you choose to use, dovetails are cheaper to manufacture as there are less parts but usually result in a taller assembly.
Attachment 22787

Thank you sir! Forgot all about Rulon, Turlon, etc...pricey stuff but impressive. Also forgot about L.C. Mason's contribution to model engineering. His books are like gold now. Thanks again for all of your contributions to HMT.

:hattip: PJ

If we are talking about use of box ways in amateur constructions, lets not forget about A. D. Mayo "Midget lathe"(improved - box ways instead dove tail - version of earlier one made by W. R. Bell, funny thing is that Bell's tool rest for wood lathe used box ways).
And there is of course Dave Gingery(I prefer his description of making box ways over L.C. Mason's one - even if end result isn't as fine).

ps. at the moment I'm working at cheap substitutes of turcite(for low end devices like those chicom cross vices or extruded aluminium compound tables you can get for 20$ or so).
Self adhesive tapes(especially capton and glass reinforced teflon ones) seems to work fine(if there only was available linen or cotton - like in tufnol/micarta - reinforced teflon tape...).