High Speed Drilling Attachment by pottyengineering

[Stewart HartParticipant @stewarthart90345]

From time to time I delve into the black art of making injectors, I've been quite successful in making the 24oz size but struggled with the smaller sizes mainly due to the difficulty with drilling the small holes, my lathe just hasn't got the speed. What I need is a high speed drilling attachment, I've been pondering this problem for some time had a couple of ideas that I've rejected:- finally I came up with this:-

What the hells that I can hear you saying well it started life as this.

A 24V high speed motor with chuck that I found on the internet (5mm output shaft) a M3 morse taper threaded 1/2" UNF and a 2 1/4" dia chunk of ally.

Cut a slice of ally off and machine up the end cap,

Now its important that everything lines up with the centre of the lathe. The motor is screwed to the end cap, so the end cap must run true with the motor shaft.

Make a temporary female centre.

Grip one end of the shaft in a chuck that you know runs true and suport the other end with the feamle centre and skim up the register dia and face of the end cap.

Clock the body up true and drill bore and tap to take the M3 morse taper abour.

Don't fix it in permanent yet

Flip it round clock it up again and rough out the bore.

Drill a few holes for cooling and wiring.

Now fix it to the Morse arbour, my lathe is M3 in the head stock so mount the assy in the head stock, and face and finish the bore to give a nice fit to the cap.

Check that everything lines up.

Proof of the pudding.

It took me just over two days to make it it seems to work OK I'll post a video over the weekend of it working

Stew

Edited By Stewart Hart on 29/01/2020 15:22:27

[Stewart HartParticipant @stewarthart90345]

[Steve CrowParticipant @stevecrow46066]

Very nice! Could you tell me what is the diameter of the motor?

Steve

[John BaronParticipant @johnbaron31275]

Very nicely done

[Stewart HartParticipant @stewarthart90345]

Posted by Steve Crow on 29/01/2020 19:24:37:

Very nice! Could you tell me what is the diameter of the motor?

Steve

Hi

its just over 40mm. There are two sizes of motor available both with chucks the smaller one has a 3mm spindle I bought one of these first but I wasn’t happy with it the spindle to flimsy so I used the bigger one 5mm spindle which is a lot more ridged.

Stew

[Simon CollierParticipant @simoncollier74340]

Interesting Stew. I have just finished my first injector from D Brown's book, the 26 oz. The smallest drill I used was about 0.7mm and I just held it in the big chuck on my lathe, with the 5/16 stock held in a 5C collet, and drilled at 1100 rpm, the fastest without changing the double motor belts. To change the latter I have to move the motor on its plate, hence, I have never changed it. The second operations on the cones was done on another lathe, with an accurate chuck, at only 500 rpm. I am about to go out and steam up my engine in the driveway to test it. I am not hopeful, as it was a very demanding job and several things did not go too well.

Recently I was searching around for your injector making stuff, but I could not find the whole story in one place and you seem not to have a web site.

[Stewart HartParticipant @stewarthart90345]

Posted by Simon Collier on 29/01/2020 22:00:15

Recently I was searching around for your injector making stuff, but I could not find the whole story in one place and you seem not to have a web site.

Hi Simon

I've posted on her a couple of times with my injectors builds **LINK**

And this is how I make high speed D bits https://www.model-engineer.co.uk/forums/postings.asp?th=142933

I'll send you a PM with my email so we can discuss injectors one to one.

Stew

 

 

Edited By Stewart Hart on 30/01/2020 08:18:10

[Stewart HartParticipant @stewarthart90345]

Posted by Stewart Hart on 29/01/2020 19:58:35:

Posted by Steve Crow on 29/01/2020 19:24:37:

Very nice! Could you tell me what is the diameter of the motor?

Steve

Hi

its just over 40mm. There are two sizes of motor available both with chucks the smaller one has a 3mm spindle I bought one of these first but I wasn’t happy with it the spindle to flimsy so I used the bigger one 5mm spindle which is a lot more ridged.

Stew

This is the electric motor I used **LINK**

Stew

[Stewart HartParticipant @stewarthart90345]

Ok as promised the video of the high speed drilling attachment in action

 

Enjoy

Stew

Edited By Stewart Hart on 31/01/2020 18:38:48

[mechman48Participant @mechman48]

Hi Stewart

Nice little HS drill you've made; I must comment that on your lathe application the first drill set up was blurred, common fault, but when you started to drill it seemed as though the drill wandered off centre, the second drill confirmed it was being pulled into the spot drill centre. It seems as though your lathe tail stock is slightly off centre, or your build is not aligned somewhere as you say it was, or maybe the drill was bent,correct me if I'm wrong ??

George.

[Stewart HartParticipant @stewarthart90345]

Hi George

I've been puzzling about that also I did this check on alignment

And everything looked good, so I'm wondering if I got the drill slightly of centre in the chuck with those small drill its easy to grip it with just two jaws I was also wondering if centrifugal force was whipping the point out, though that doesn't seem to happen when I had it in the mill. It didn't seem to effect it much though.

Thanks for your interest

Stew

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