My new Toy!! Lathe question

[kiyoukan]

so did you use the heatup method or just found a better drill bit?
or did you just need to work it up in steps?

 

[Kevlar]

I worked this one up in steps and it's still about 1mm too big, so 0.5mm on each side. Not bad but I'd rather have it tighter.

I'm going try the next small size down they have at the shop and see what happens. If that doesn't work, I'll try the heatup method. And if thaaaat doesn't work, I'll start looking to buy some other bits.

 

[Mohrenberg]

I work my way up to 15/32, once i get that hole drilled, they are usualy still tight enough they'd have to be pressed in with a vice, so while the bit is inside the sink I press down on it with my hand and start backing it out. this makes it shave a little extra and help the module fit better.

This method doesn't work as well with copper though Copper makes me want to punch a baby.

Oh, and my bit was labeled as 11.9mm on the packaging, while other 15/32 bits said 12mm

so who knows.....

standard sizes are so dumb, i like metric much better....unfortunately i live in the united states where everything is ass backwards.

 

[Kevlar]

I work my way up to 15/32, once i get that hole drilled, they are usualy still tight enough they'd have to be pressed in with a vice, so while the bit is inside the sink I press down on it with my hand and start backing it out. this makes it shave a little extra and help the module fit better.

Yeah, it must be different manufactures, I'll have to try different ones because my 15/32 comes out a tad big.

Copper makes me want to punch a baby.

LMFAO!! :crackup::crackup::crackup: This made me laugh so freakin hard. Does that make me a bad person? :thinking:

standard sizes are so dumb, i like metric much better....unfortunately i live in the united states where everything is ass backwards.

I said this to a couple different people in different shops I know of and they look at me like I'm a communist!!!

 

[Morgan]

As with anything in engineering drill bits are also made to tolerance. +/-0.1mm is not unusual at all. That's why they are so cheap and even two drills from the same manufacturer can therefore differ in diameter by up to 0.2mm from each other. I would also not recommend turning down a drill bit and go the Reamer route. Reamers, are more expensive and work in the same way as a drill but with more flutes at a shallower angle and are precision ground so a 12mm reamer will give you a hole from 12.00 - 12.02mm. Cutting and feed speeds are generally slower than drilling though so you'd have to look that up. They should only really be used to remove a small amount of material so you have to drill pretty close to the size you want and not start chewing huge 2mm cuts with one! That'll ruin your reamer real quick!

A far easier way to get the correct fit is to have on hand a selection of modules to match to your hole. The Aixiz modules I have fitted to turned heatsinks themselves have quite a large tolerance range, (+/-0.2mm IIRC), so you will generally have one that fits better than another.

Personally I always bore the hole myself to the smallest module I have and never drill for the final fit. This way, if I over cook it, I know I've got another module slightly larger that'll fit, (hopefully!). I also don't like the press fit style either as the different materials expand and contract at different rates and this could eventually mean the module becomes loose, or binds up to prevent easy repair or replacement but that's just personal preferences I guess.

To gaurantee a hole size to 0.02mm? Ream it! Simple as...

M



P.S. What sort of lathe is that in the pic?

 

[Kevlar]

As with anything in engineering drill bits are also made to tolerance. +/-0.1mm is not unusual at all. That's why they are so cheap and even two drills from the same manufacturer can therefore differ in diameter by up to 0.2mm from each other. I would also not recommend turning down a drill bit and go the Reamer route. Reamers, are more expensive and work in the same way as a drill but with more flutes at a shallower angle and are precision ground so a 12mm reamer will give you a hole from 12.00 - 12.02mm. Cutting and feed speeds are generally slower than drilling though so you'd have to look that up. They should only really be used to remove a small amount of material so you have to drill pretty close to the size you want and not start chewing huge 2mm cuts with one! That'll ruin your reamer real quick!

A far easier way to get the correct fit is to have on hand a selection of modules to match to your hole. The Aixiz modules I have fitted to turned heatsinks themselves have quite a large tolerance range, (+/-0.2mm IIRC), so you will generally have one that fits better than another.

Personally I always bore the hole myself to the smallest module I have and never drill for the final fit. This way, if I over cook it, I know I've got another module slightly larger that'll fit, (hopefully!). I also don't like the press fit style either as the different materials expand and contract at different rates and this could eventually mean the module becomes loose, or binds up to prevent easy repair or replacement but that's just personal preferences I guess.

To gaurantee a hole size to 0.02mm? Ream it! Simple as...

M



P.S. What sort of lathe is that in the pic?

The lathe is a SouthBend.

Thanks for the tips Morgan, I appreciate it. :beer: I just got some more modules in the mail today so I'll take them all to the shop with me.

 

[Morgan]

My pleasure Kevlar!

Happy turning... !

M

 

[Mohrenberg]

I got this reamer in the mail today
12mm Metric Chucking Reamer Ream cutter Tool 12 mm - eBay (item 360315955736 end time Dec-02-10 06:59:19 PST)


it works great. Seems to cut the holes perfectly. I don't even know the size bit i work up to before i use the reamer (it's not labeled) but its like .445" in diameter

the reamer comes really long so i chopped it in half to save some space.

I'm hoping this will work just as well when i make these copper heat sinks....last time was a nightmare trying to get that aixiz hole just right.

 

[kiyoukan]

Those are nice.
That store is about an hour away.
i have bought a few things from them.
they even sell 12mm drill bits

 

[Kevlar]

I got this reamer in the mail today
12mm Metric Chucking Reamer Ream cutter Tool 12 mm - eBay (item 360315955736 end time Dec-02-10 06:59:19 PST)


it works great. Seems to cut the holes perfectly. I don't even know the size bit i work up to before i use the reamer (it's not labeled) but its like .445" in diameter

the reamer comes really long so i chopped it in half to save some space.

I'm hoping this will work just as well when i make these copper heat sinks....last time was a nightmare trying to get that aixiz hole just right.

I thought about using a reamer but a friend of mine has had a machine shop for 30 some odd years or so. He must have hundreds of thousands of dollars worth of just tools, freakin unbelievable. His shop is too busy for me to get in there on the machines but I do have free access to all the aluminum stock and tools I can carry!!

The end mill I was using was a 15/32 but was pretty long so I think it was wobbling/flexing or something causing the hole to be a little big so I borrowed a much shorter end mill, much better quality. It read "PTD CO USA" on it. But anyway, I worked my way to that one and it's a perfect fit!!!

So today I had my third try at the heatsink, I didn't really like what I produced before. Today's came out really good, I'm pleased with it.

This is the first one I made. See the bevel? That was on the stock piece when I started and I thought it would be OK but I didn't like it plus the module sits farther back and is hard to focus with the way the head of the torch is shaped.

So this is the one I made today. It protrudes out the front a little bit so you can focus easier.

Nice tight fit!! :yh:

Here is another shot with my somewhat pathetic focus adapter (first try).

Next time I wont' cut if off the stock before I use the knurling tool.

I'm realizing this stuff takes time and I'm gaining a lot more respect for you machinist out there. Especially you mo, you basically do it for free!!!

This heatsink and focus adapter took me about 2 + 1/2 hours. I'm guessing the more one does it, the less time it takes.

 

[Morgan]

I got this reamer in the mail today
12mm Metric Chucking Reamer Ream cutter Tool 12 mm - eBay (item 360315955736 end time Dec-02-10 06:59:19 PST)


it works great. Seems to cut the holes perfectly. I don't even know the size bit i work up to before i use the reamer (it's not labeled) but its like .445" in diameter

the reamer comes really long so i chopped it in half to save some space.

I'm hoping this will work just as well when i make these copper heat sinks....last time was a nightmare trying to get that aixiz hole just right.

.445! I like it!

Generally, the closest drilled hole you can get before being over sized is good but there are charts for reamers. Overkill in our use probably, but they are there.

You chopped it in half Mo? Which half? Did you chop off the cutting end or chuck end? Either way, be sure that if you chopped the cutting end that your new tool is running true with no burrs on the cutting flutes because they are precision don't forget. Not getting a good start in the hole due to uneven flutes will somewhat negate the purpose of the tool, (not lecturing but I wouldn't have done that). The important thing to remember is a slow cutting speed, slow feed rate and dwell at the end of your hole, (dwell means let it sit and turn for a while), and slowly retract. If you've got no definite speeds to choose from, (my lathe has fast, medium and slow!), it's an art so take your time. I've been doing a fair bit of 12mm reaming this week and it took a while to get it sorted! Cutting fluid is your friend!!! Just some fine oil will do if you have nothing else and this will much improve the finish.


^ Nice finish inside that thru-hole Kevlar!

M

 

[Kevlar]

.445! I like it!

Generally, the closest drilled hole you can get before being over sized is good but there are charts for reamers. Overkill in our use probably, but they are there.

You chopped it in half Mo? Which half? Did you chop off the cutting end or chuck end? Either way, be sure that if you chopped the cutting end that your new tool is running true with no burrs on the cutting flutes because they are precision don't forget. Not getting a good start in the hole due to uneven flutes will somewhat negate the purpose of the tool, (not lecturing but I wouldn't have done that). The important thing to remember is a slow cutting speed, slow feed rate and dwell at the end of your hole, (dwell means let it sit and turn for a while), and slowly retract. If you've got no definite speeds to choose from, (my lathe has fast, medium and slow!), it's an art so take your time. I've been doing a fair bit of 12mm reaming this week and it took a while to get it sorted! Cutting fluid is your friend!!! Just some fine oil will do if you have nothing else and this will much improve the finish.

I was looking at the link Moh provided. In the description it states that it was 7" long and it appears that the working end of it is only about 2 -- 2.5" long. So I think he just made it shorter to avoid any wobble or walking that the longer tools seem to suffer from.

^ Nice finish inside that thru-hole Kevlar!

M

:thanks:

 

[Mohrenberg]

the cutting end is only a couple inches long, and then it was like 8 inches of drill rod, so i chopped it down so that i can stick it in the dril chuck and it basically all cutter sticking out.
I initially chopped it off with the band saw, and then i put it on the lathe and faced it off, rounded the edges and gave the end a light sand. Looks like it was made to be that short

in it's original length, this reamer would not even fit on my lathe. I've got a 10" bed, my tailstock and drill chuck take up a good 4 inches (random guess) and this bit is 7" long.
Now it more like 3...
I left just enough blank drill rod on the end to insert it into my drill chuck all the way. So everything thats protruding from the drill chuck is cutting surface of the reamer.

it's definitely a great addition to my random bits and bobs. I'll be playing with the copper tomorrow so then i'll really get to see if it was worth it.

.445! I like it!

Generally, the closest drilled hole you can get before being over sized is good but there are charts for reamers. Overkill in our use probably, but they are there.

You chopped it in half Mo? Which half? Did you chop off the cutting end or chuck end? Either way, be sure that if you chopped the cutting end that your new tool is running true with no burrs on the cutting flutes because they are precision don't forget. Not getting a good start in the hole due to uneven flutes will somewhat negate the purpose of the tool, (not lecturing but I wouldn't have done that). The important thing to remember is a slow cutting speed, slow feed rate and dwell at the end of your hole, (dwell means let it sit and turn for a while), and slowly retract. If you've got no definite speeds to choose from, (my lathe has fast, medium and slow!), it's an art so take your time. I've been doing a fair bit of 12mm reaming this week and it took a while to get it sorted! Cutting fluid is your friend!!! Just some fine oil will do if you have nothing else and this will much improve the finish.


^ Nice finish inside that thru-hole Kevlar!

M

 

[Flaminpyro]

Have fun Mo with the copper it has a mind of it's own and dose not like to play well with others till you learn it's secrets which are many

 

[AUTO XX]

Ok, don't laugh but one of the first things I tried was to drill my module hole through a little tight (nearest bit size) then I took the back of an aixiz module and cut a slight right hand spiral up it with a diamond abrasive cutter in the dremel. I cut deep enough that I wouldn't go through the brass but it had a slightly less than square edge. After I cleaned what little burr the dremel had left with 1500G wet/dry I threw it in the chuck mounted in the tailstock and bored my hole from both sides of the heatsink.
The hole matched a new module perfectly (of course) and I pressfit it in.
All I had for tooling at the time was a boring bar that was too big and a few other tools for cutting, parting and facing.
Low tech solution for a high tech project

 

[Kevlar]

Question about copper stock. I was looking at a couple of sites tonight and they sell different kinds.

C101 (oxygen free)
C110 (ETP)
C145 Terrurium
C147 Sulfer
C182 (Class 2) chromium-free

Which one should I get for the heatsinks we make?