Novice beginner

New problem,

I need to drill through the shaft that the Perch bracket sits on its 3/4" dia

each time I try on a sample peice the drill runs out - off centre by the time it comes out the other side

any tips on how to keep the drill true as it drills

Hi There

Drill should not wander if you use a sharp drill after a centre drill.

However, put the shaft in the dividing head, drill undersize halfway through, index 180 degrees and drill the other half.

Follow through with another undersize drill all the way through finish with size drill or ream.

regards David

Edited By David Clark 1 on 20/02/2012 11:08:49

Hi David,

The only problem is I don't have a dividing head...

But thanks for the quick reply

Do you have a boring head? that way you can drill through say 1/2" and then take the rest out in stages with the boring head which will run true.

If not again drill 1/2" or 5/8 and then plunge cut with a slot drill or even an end mill would do.

J

Hi Kerbtrawler

Are you trying to drill through a 3/4in. bar or drill a 3/4 hole through a bar or what?

regards David

Sorry I should have been more clear I am trying to drill a 3/16" hole through a 3/4" round bar that also has a collar on it that measures 1 1/4" od

I have to put a retaining pin through them both, I will see if I can take a photo and post it

cheers

Hi kerbtrawler,

Are you using a pillar drill and just lining up to a centre pop mark or are you using a milling machine with the 3/4" bar in a machine vice that has been accuratly aligned so the drill is centred on the bar. When you centre drill the bar go deep enough so that the countersunk pilot hole is almost 3/16" dia. to give the drill the best possible start. Drill the hole initially with the shortest drill you have that is just a little les than 3/16". (If you use a very small for the initial hole it is more likely to wander.) If I was doing this (Particularly if you are just using a pillar drill.) I would put the collar on the bar and drill both in the one operation. This means the holes will line up even if they are not accuratly through the centre of the bar. (This would not neccassarily be true if you then turned the collar through 180 Deg.)

Les

Hi Kerbtrawler.
That is what I thought, small hole.
Bore a square block out to fit on the bar, drill and tap and use a grub screw to nip the block to the shaft.

Put the bar in the vice, squaring up with a square.

Drill undersize halfway through, turn the bar and block over, drill through from the other side.

Drill through the collar, from both sides if neccesary.

Assemble both parts and open up to finished size.

regards David

Now thats the kind of idea I can manage, I just couldn't get my head around how I could go 1/2 way, turn the job over and hope to hit the same spot.

Thank you very much for all of the suggestions, I will report back in the morning on how succesful it is

cheers

Sorry,

forgot to say that Yes I am using a bench pillar drill with Added guidance that I have fitted to keep the mandrel true as there was a lot of movement even tho' it was new ( and cheap) ( and nasty)

Hi kerbtrawler,

I notice from one of your first posts that you have a Warco GH1224 lathe and a vertical mill. I wonder why you do not use the mill ?

This is a variation of David's suggestion using your lathe. Mount the square bar on the cross slide of your lathe with suitable packing under it to bring it up to be about centred at centre height. (Mark it so you know which is the bottom surface. True it up with a dial guage to be parallel with the axis of the lathe. Move the cross slide to bring the square bar about centered in the horizontal direction and lock the cross slide. Now drill it with a drill in the lathe chuck and then bore it with a boring head or boring bar in the lathe chuck to 3/4" bore. Turn the square bar through 90 Deg on the cross slide USING THE SAME PACKING and the SAME SURFACE DOWN. Again check the alignment with a dial guage. Drill a hole and tap a hole in the block for a grub screw. If you now slide your 3/4" bar into the block and clamp it is exactly at centre height and at right angles to a drill in the lathe chuck. You should now be able to trill the hole exaclly on centre.

Les.

Just reporting Back, Success

I varied the idea's and mounted the part onto an angle block which i fitted to the modified top slide of my Warco 1224 and used a centre bit in the chuck to spot the ring and then went through with a 3/16" and then finished it off with a No 11 drill

I had previously secured the ring to the shaft using Gorilla glue which gives just enough grip to keep it in place

I will post some other photo's once I know how

Many thanks for the idea's

Edited By kerbtrawler on 21/02/2012 09:09:53

Here is what I did

There are a couple of more photo's showing the mod to the top slide and so on

cheers

Hi kerbtrawler,

Glad you managed to do the job and in particular adapt an idea to suit the items to hand rather than just doing exactly as suggested.

Les.

Hi kerbtrawler, please excuse my ignorance but what is 'Gorilla glue'?

ChrisH