Need 4 holes drilled & tapped

[Gragson]

Can anyone drill & tap these 4 holes marked red, accurately and flat to base for the fixture pictured into the ali slab M6 x 1.0 - 23mm approx depth.
Ali slab is 300 x 250 x 60 - holes into the 60mm section as pictured. Or know of any place near North bucks? Cash / payment and can deliver & collect if around an hour.
Thanks.

 

[Agroshield]

You would need to supply information specifying the left-right and up-down position of the holes on the 300 x 60 face of the slab.

 

[Maker]

How are you supposed to tap M6 into a 7.3mm hole?

 

[Brad93]

How are you supposed to tap M6 into a 7.3mm hole?

Some sort of cap head? Although I think M6 is more like 9.5mm

 

[willie.macleod]

Looks like the base for Hobbymat BFE65 milling head? What is it you are trying to achieve with this, as above some of the figure don't tally with the instructions?

 

[Gragson]

You would need to supply information specifying the left-right and up-down position of the holes on the 300 x 60 face of the slab.

Bottomed centered onto the 300 face

How are you supposed to tap M6 into a 7.3mm hole?

The drawing is the flange not the base

Some sort of cap head? Although I think M6 is more like 9.5mm

The hole in the flange is 7.3 but recessed at start to accept M6 cap head

 

[Brad93]

Bottomed centered onto the 300 face

The drawing is the flange not the base


The hole in the flange is 7.3 but recessed at start to accept M6 cap head

Counterbore is 11.25mm and clearance hole is 6.1mm?

 

[Gragson]

Counterbore is 11.25mm and clearance hole is 6.1mm?

Counterbore yes pretty much but clearance is more like 6.75 but M6 cap head is the go

 

[Maker]

A counterbored hole (Especially one with such massive clearance) doesn't provide a precise location, so you don't need a crazy amount of precision in the holes, you'll easily achieve the accuracy you need with a steel rule and a cordless drill.

 

[Kram]

a cordless drill.

Difficult to get square. Generally unless you are very good at it, will be atleast 5, possibly 15 degrees out.

If you dont have any luck post it here and back, I can do it on the lathe. Best if you mark out the holes with a transfer punch, in my opinion, then they will be exact.

 

[Gragson]

A counterbored hole (Especially one with such massive clearance) doesn't provide a precise location, so you don't need a crazy amount of precision in the holes, you'll easily achieve the accuracy you need with a steel rule and a cordless drill.

I can do better than that but yes I will have a crack at it on the pollard, the slab was expensive so don't want to mess it up, centering on the slab is not that critical but the flange/foot does need to be flat as poss with the slab

 

[Maker]

the slab was expensive so don't want to mess it up

That's why I haven't volunteered to do it, I don't want to buy you a new one when I snap a tap.

 

[Gragson]

Spurred on by @Maker slightly insinuated

Measured, drilled, taped, pretty happy with that.



@willie.macleod yes its a hobbymat mill, I know my instructions may not have tallied, but I know what I meant

Bike stand is not is final work place, need to get things sorted in the tardis, but M12 bolted through table, base and bike stand - pretty solid but checker plate is no good for this, need to make space on the bench

 

[Agroshield]

...the flange/foot does need to be flat as poss with the slab

If there is any doubt on this (the edge of the plate looks sawn), smear the contact surface with JB Weld before you tighten up the bolts. After 24h it will have a good bearing surface.

Suggest you check the tram of the machine before you undertake anything critical.

 

[Brad93]

No way that lump of steel is flat unless it's been ground? But it looks Saw cut

 

[Maker]

Once you've got the column as square as you can get it to the table, it might be worth drilling, reaming and pinning the joint so it can never move. Not that there's space on the casting to do that, it's just a thought.

 

[Brad93]

I'm just having another look. Have you got any adjustment for tram?

Or will you be shimming it?

 

[Gragson]

If there is any doubt on this (the edge of the plate looks sawn), smear the contact surface with JB Weld before you tighten up the bolts. After 24h it will have a good bearing surface.

Suggest you check the tram of the machine before you undertake anything critical.

Thank you, that is a good tip, base will be a permanent attached fixture so I will do that.
The plate is sawn but quite true, I have 8mm glass flat plate that I will give it a going over with on grades of fine paper & lube, and the mating foot for that matter. Done me well on loads of lawnmower and small motorbike heads.

No way that lump of steel is flat unless it's been ground? But it looks Saw cut

Yes its sawn - its aluminium not steel.

I'm just having another look. Have you got any adjustment for tram?

Or will you be shimming it?

I'm not sure yet but there are plenty of options for squaring, I need to test.
Perspective being tho it is a mini mill, although well respected by the ones who own them.
Propa old GDR mini kit