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To get recommended speed and feed, you need to know both part material and tool material. Sometimes it is also needed to know coolant, lubrication, machine specs.
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Hello,
I need some help I need to ream a hole .250 dia what's the correct speed and feed ?the hole its blind.
Thank you
To get recommended speed and feed, you need to know both part material and tool material. Sometimes it is also needed to know coolant, lubrication, machine specs.
http://www.kirkcon.com/
The material ist aluminum 6061 t6 and the reamer ist HHS .2495 dia.and also when I do the program do I do the pecking or just go straight to the depth?Originally Posted by txcncman
From Machinerey's Handbook: 400 SFM and 0.016" per revolution (not per tooth).
Do you need the formula to calculate RPM from SFM?
Feed all the way in. You can feed out at a higher feed rate if you wish, usually double.
http://www.kirkcon.com/
That would help if you can share the formula. I'm new on this I'm switching from sheet metal to machining.
From personal experience..note this is MY practice ONLY... others may have their own opinions, some better, some worse....
I run reamers slowly, around 25-50sfm typically, 50-100sfm for the 6061T6, with a good heavy feed (in this case I agree with the .016/rev), and start with a hole that's at least .006" smaller in dia than the req'd finish ID. You want plenty of material for the reamer to work with, but not so small you get too big a chip load.
Depending on the finish hole tolerance, sometimes I'll spot drill for the drill, then after drilling & reaming come back and touch the hole again with the spot drill just a touch deeper (print allowing) to remove any potential bell-mouth from the initial reamer as it gets started in the hole.
I don't like the idea of "peck reaming". They like a good steady feed...get in, get out.
(for the hobby guys... if your hole is coming out a little undersize, or if you need to enlarge it a tad, put a toothpick or sliver of wood in a flute... done carefully, you can cheat around having over/under reamers)
Ok I like that trick the toothpick But what is that do? or how do you put it on ? just want to learn as many tricks as I can.
tx
The formula to get RPM from SFM is:
RPM = (SFM X 12) / (Diameter X PI)
The toothpick trick probably does one of 2 things. It might cause more drag on the tool, which in turns causes the flutes to flex out a little, taking more material. Or, more likely, it causes the ream to cut off center, which effectively takes more material also. I have never used this trick. I am just guessing at why it might do what it does. I control finished reamed size by: Starting drilled hole size. RPM. Feed rate. Changing to another tool. Honing the flutes of the ream.
http://www.kirkcon.com/
I run .2505 dia reamers everyday on hundreds of holes. 1 reamer will last generally 3-4 months sometimes longer depending on your tol. and your coolant % is a must
I run a .234 drill peck drilling then the reamer at 2500rpms and 20IPM
Any faster RPM you will get chatter.
for anything over 1" thick reamed holes I peck ream at 2500 rpms and .200 pecks 15ipm then rerun the reamer at 20-25 IPM.
you have to be careful with peck reaming as if you dont have a perfectly good hole it will walk. also run a drill closer to the finish size.
the only reason I peck ream is do to galling ie material build up) sometimes you have to run another reamer like a .245-.247 1st(pecking) then the finish reamer after.
I too don't like the peck cycle for a reamed hole.Maybe for a 1 deap hole I'll ream .500" retract blast air in the hole and the reamer then finish. I like to leave very little material for reaming , like .010-.015". My rpm is low too , between 200-500 rpm on a small reamer like that. Some may not agree with what I do but my holes are spot on.
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