[ashes-man]

I am building myself a fixture plate, picture attached. Made from a chunk of 25mm thick G350 steel I found lying around, approx 300 x 400mm. I don't often work with steel and if I do its small stuff. I am after some advice on what tooling I should use to do the drilling and tapping as I need to buy most of it anyway. In the plate I need to:

- Drill and tap about 85 M10x1.5 holes (through hole)
- Drill about 85 4.2mm holes (through hole)
- Drill and ream the top half of the 4.2mm holes for 6mm dowels (10mm deep ream)
- Tap the lower half of the same holes to M5x0.8
- Drill and ream 64 holes for 4mm dowel pins (8mm deep ream)

I have squared up and faced the plate in the manual mill. I will drill and counterbore the large mounting holes also in the manual mill, I have tooling suitable for that.

I want to do the drilling in my small CNC (Centroid converted Mazak Impulse), as a lot of holes to drill by hand and why have a dog and bark yourself!

I need some advice on buying tooling that will last the distance without breaking the bank as unlikely I will use most of these tools very often. It is for my home shop, so entirely at my cost. Good quality, reasonable price tooling is very hard to get in New Zealand. I have found BB tools from Aliexpress to be quite good so far, thoughts?

Also things like feeds and speeds, order of operations, coolant, no coolant (my machine has air or flood coolant). Is tapping M10 OK in a normal ER32 collet?

Thanks in advance

[peteeng]

Hi Ashes - I've found the data from Suttons to be good on their feeds and speeds. If you have flood then always use it...Peter

https://suttontools.com/eu/catalogue-media/brochures/

[CNCMAN172]

I would buy some solid carbide drill bits and use coolant. Carbide will stay sharp longer and cooling will avoid heat buildup which will dull the drills. I would also do peck drilling which puts less load and drag on the drills

[ashes-man]

Thanks, I have used the Sutton catalog before, they are pretty clear and simple. If only I could buy Sutton tools here, they are made just down the road!

[ashes-man]

I would buy some solid carbide drill bits and use coolant. Carbide will stay sharp longer and cooling will avoid heat buildup which will dull the drills. I would also do peck drilling which puts less load and drag on the drills

I have ordered some carbide tools, so will get into this project in a few weeks. Will see how the mid range Chinese tooling holds out! I have read that pecking should be avoided with carbide and just go hard out all the way to the bottom. But, I think a 25mm hole would have a giant helicopter chip flying around by the bottom or a birds nest around the drill at minimum if went the whole way without pecking!

[metalmayhem]

I have read that pecking should be avoided with carbide !

Correct , if a chip falls to the bottom of the hole then there is a very high chance of destroying your carbide bit . hss and cobalt drills are much more forgiving . If they are well designed bits then bird nesting shouldn't be a problem , otherwise you can program a chip break .
For the sake of a 1 off I'd have went with cobalt drills , it's much more economical

[ashes-man]

Correct , if a chip falls to the bottom of the hole then there is a very high chance of destroying your carbide bit . hss and cobalt drills are much more forgiving . If they are well designed bits then bird nesting shouldn't be a problem , otherwise you can program a chip break .
For the sake of a 1 off I'd have went with cobalt drills , it's much more economical

You are probably right. Knowing my luck I will probably break a carbide drill in the bottom of a hole and it will be stuck in there forever as a reminder! To be honest I don't know why I ordered carbide drills now, I am not even sure I meant to. It was late and I was getting impatient. I ordered HSS drills locally for doing the mounting holes!

This might not be a one off, I suspect I might end up making a few more smaller fixture plates.

Maybe I will not program a full retract pecking cycle like I normally use and instead just use a chip breaking cycle with a small retract every few mm. That is the sort of stuff I am not sure on. What are safe feeds and speed and retracts etc.

How do carbide drills go when they break through the bottom of a hole? Does that chip them?

[metalmayhem]

they don't usually chip or break on through holes and the material your looking to cut is pretty soft . The retract speed really doesn't matter that much but I'd keep the retract height to a minimum and just enough to clear the bottom to break the chip .

Good carbides can take a a heavy and fast cut . For example I used to run 3/8" kennametal dynapoint drills in 4140 at 4500rpm and 50ipm , but that was also with through spindle coolant .
Without through spindle and using flood I think a 3 flute would be a better choice for getting coolant down to the tip . I hate to say it garr makes a decent 3 flute , or at least they used to ( I don't usually like garr tools) . The problem with these tools is the price point for the average guy

I do my own thing now and I'm quite a few years outside the heavy industrial loop so I don't have a need for carbide drills . A while back I was doing some prototyping and got some "quality" chinese carbides because I needed to ensure there was no drill wander . I wasn't impressed with the grinds and I felt more comfortable running hss or cobalt faster , and this was only on aluminum . The end result with those drills was me drilling with a smaller hss and chasing the hole with the carbide drills which is usually a no no but the holes were perfectly straight

Anyhow , If you can get feed and speed recommendations from the seller then that should be the best starting point . The seller should know the most optimal speed for those drills .
And , I'd suggest upping your coolant concentrate considerably since you'll want the best amount of lube getting down to the tip

Btw in regards to your question about an m10 tap in an er32 - that fine and shouldn't be a problem . Just have the tool choked up as far as you can and crank the holder tight . Once again , a higher coolant concentrate helps with tapping , or , if your a patient man then pour cutting oil into the holes as you go along is best

[ashes-man]

they don't usually chip or break on through holes and the material your looking to cut is pretty soft . The retract speed really doesn't matter that much but I'd keep the retract height to a minimum and just enough to clear the bottom to break the chip .

Good carbides can take a a heavy and fast cut . For example I used to run 3/8" kennametal dynapoint drills in 4140 at 4500rpm and 50ipm , but that was also with through spindle coolant .
Without through spindle and using flood I think a 3 flute would be a better choice for getting coolant down to the tip . I hate to say it garr makes a decent 3 flute , or at least they used to ( I don't usually like garr tools) . The problem with these tools is the price point for the average guy

I do my own thing now and I'm quite a few years outside the heavy industrial loop so I don't have a need for carbide drills . A while back I was doing some prototyping and got some "quality" chinese carbides because I needed to ensure there was no drill wander . I wasn't impressed with the grinds and I felt more comfortable running hss or cobalt faster , and this was only on aluminum . The end result with those drills was me drilling with a smaller hss and chasing the hole with the carbide drills which is usually a no no but the holes were perfectly straight

Anyhow , If you can get feed and speed recommendations from the seller then that should be the best starting point . The seller should know the most optimal speed for those drills .
And , I'd suggest upping your coolant concentrate considerably since you'll want the best amount of lube getting down to the tip

Btw in regards to your question about an m10 tap in an er32 - that fine and shouldn't be a problem . Just have the tool choked up as far as you can and crank the holder tight . Once again , a higher coolant concentrate helps with tapping , or , if your a patient man then pour cutting oil into the holes as you go along is best

Thanks. Heaps of good advice there. Coolant concentration was something I was worrying about. I usually run about 5% which is manufacturers recommendation. Not sure I am brave enough to put my hand in there and manually put oil in the holes though. Although I could rig up a long plastic pipe I guess. Run air to clear the chips.

I am OK with running the tools at lower feed rates/RPM. I know you need a minimum feed per tooth, but I am not going for fastest cycle time here. Just trying to learn and not trash anything at the same time. . .