Reaming Holes in Fixture Plate – What Type of Reamer

[not done it yetParticipant @notdoneityet]

Posted by Vic on 24/10/2020 11:23:15:

These days you can get centre cutting end mills so I’d try one of those rather than a slot drill. As said I’d try it in some scrap first and perhaps stone the cutter as required if the hole ends up loose.

…..

If the material is pilot-drilled a larger number of flutes (than a slot drill) can be used for drilling with an end mill. I like the idea of a carbide end mill but stoning it to cut smaller might be a task in itself?

[Rod RenshawParticipant @rodrenshaw28584]

As there are to be many more holes than dowels it might be worth making dowels to fit the holes.

That is, drill or ream etc the holes first, by your chosen method, the precise size being less important than that they are all the same, and then make dowels to fit. Turned down silver steel left unhardened would last a fair length of time in holes in ali plate. Turning the pins would, I think, be easier than trying to reduce the size of a mill while leaving it sharp enough to cut ali.

More methods than you can shake a stick at!

Rod

[Colin HeseltineParticipant @colinheseltine48622]

For today just decided to drill and tap holes, whilst I wait for reamer and dowels. But will test all options suggested.

Picture below shows plate after spot drilling all (well most of) the holes and then drilling a 3mm through hole. The fixture plate is sat on a 3mm plywood base to prevent damage to the table. I did not want to raise it any further as the tenons on the bottom of the plate are locating it in the central slot on the table.

I said I had drilled most of the holes. No matter which way I moved the table in the Y axis and moved the head forward and backwards there was no way I could see to drill the final row of holes. Rather than disturb the current setup I will complete all the tapped holes and all bar the last row of 8 reamed holes prior to moving the milling head to to an extended position to get to the last row. Will have to use the edge finder on the outside edge and then move in the required 15mm or possibly it would be more accurate to fit some dowels in the last but one row and take a measurement from there.

All the holes to be tapped have been drilled 8.5mm and have just tapped 18 of them by hand after tea. The next 18 can wait till the morning, need to give my back a rest.

Colin

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