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View Full Version : Questions for step pulley mill/drill users.



Big T
04-11-2009, 12:16 PM
What do you guys do as far as speeds are concerned. Do you try to find a RPM setting and try to leave it there? It is kinda a pain to always keep changing the belts.
I had mine set for 780 rpm, good for face mill but that was to quick for drilling and boring.
Now I have it in the 440 rpm and will try that to see if it works for milling and drilling.

What rpm do you use, or do you keep changing for each job?

I can see a VFD in the future, that would be handy.

bob ward
04-11-2009, 12:32 PM
What do you guys do as far as speeds are concerned. Do you try to find a RPM setting and try to leave it there? It is kinda a pain to always keep changing the belts.

Guilty. 500RPM

deltaenterprizes
04-11-2009, 12:54 PM
I switch the high low range, low for steel, high for aluminum.

Scishopguy
04-11-2009, 01:17 PM
Speed changing on a BP is not that big a deal. You need to pick the speed closest to what the operation and material call for. Be sure that when you change into back gear, that you mesh the gears ( by hand turning the spindle ) before you put power to it. That said, I can highly endorse getting a VFD. I worked with belt drive BP's for 30 years without a thought of the trouble of changing speeds but have fallen in love with the VFD on my mill. You can dial in exactly the speed you need, even while cutting. It is well worth the cost.

Doc Nickel
04-11-2009, 04:30 PM
What do you guys do as far as speeds are concerned. Do you try to find a RPM setting and try to leave it there?

-Oh heck no. I run everything from 1/8" ball-end mills to 1-1/2" twist drills, sometimes on the same setup.

If you have trouble swapping belts, you might look into modding the mill to make it easier- like swapping bolts for a stud and nut with a handle, or modifying the guards, etc.

A VFD would definitely help, but you'll still need to occasionally swap belts.

Doc.

NickH
04-11-2009, 04:32 PM
A VFD is your friend here, I'm even fitting one to my variable speed pulley equipped Mill Drill, mainly to allow 3 pase motor use but it'll get me speeds from almost nothing to 4000rpm plus if the whole thing will take it. (7000rpm potential but I think that's fantasy on a big Mill Driil and it is big :D )
Regards,
Nick

gnm109
04-11-2009, 04:52 PM
I removed the large belt guard on top of the machine and built a shorter guard that just covered the pinch points. That way, it's easier to access the belts and idler pulley for speed changes. I also added levers to the pinch bolts that held the head to the column so I didn't have touse a wrench. It's a pain the change speeds otherwise.

Sorry I don't have pictures handy. they're on my other computer.. I'll get them for you tonight.

bruto
04-11-2009, 08:15 PM
I tend to be lazy in changing speeds too, but on my Old Enco mill drill, I made a couple of modifications that make changes easier. First, I put hinges on one side of the guard, so it can be opened without removing, and cut a slot where column passes through, so that it can be raised easily even at lower settings. I also replaced the bolts that hold the center idler carrier around the column with longer bolts, with a stiff spring between the head and the carrier. This allows me to shift the idlers without loosening bolts, and also prevents those bolts from coming loose in use.

dockrat
04-11-2009, 08:51 PM
You guys are making me appreciate my gearhead mill more and more all the time. :p

Big T
04-12-2009, 10:59 AM
Perhaps I have being a little on the lazy side when it comes to changing the belts. My lid has the hinges on it , but the idea of a spring for the carrier sounds like a great idea.

I don't have any gears for the high/low range on the mill.

Thanks guys

bruto
04-12-2009, 01:20 PM
My crappy little digicam hates to focus in dim conditions, but here's a picture of the above minor mod to the idler carrier bolts. The springs, of unknown original source, are very stiff:http://img26.imageshack.us/img26/5922/encopressidlermod.jpg (http://img26.imageshack.us/my.php?image=encopressidlermod.jpg)

A.K. Boomer
04-12-2009, 01:42 PM
I just use a spring washer sandwiched between two regular ones, I change speeds for every tool change - unless I get lucky and the different tool needs the same speed (I.E. center drill/drill)

chiphead42
04-12-2009, 02:19 PM
Hello I have been trying to figure a way to replace the 2 locking bolts on my round coloum mill/drill, with some sort
of cam device. Anyone done this? Any ideas/suggestions?
Thanks chiphead42

Big T
04-12-2009, 09:29 PM
Hello I have been trying to figure a way to replace the 2 locking bolts on my round coloum mill/drill, with some sort
of cam device. Anyone done this? Any ideas/suggestions?
Thanks chiphead42

Check out the Feb/March issue of Machinist's Workshop. In the tips and tricks there is a article on exactly that. He made two longer nuts. put a cam on each and hooked them together by a flat steel. On the bottom nut is a lever that when moved will loosen and tighten the nuts.

I hope that makes some sense, maybe some one that has it can explain it better, or scan the picture.

airsmith282
04-12-2009, 10:39 PM
my mill has a variable speed control , but i only use my mill for milling for the most parts very rare for drilling, i have a drillpress for my drilling but if the job has to be really persision then i use the mill and i set the speed depending on the metal iam drilling or boring into.. i love dial a speed control on the mill,,

Carld
04-13-2009, 12:24 AM
I never have found it to be an issue to change the belt on the pulley for speed changes. It's easy once you discover THE WAY. I admit the variable speed head is handy but the pulley head is not all that bad. Only two shops I have worked in had variable speed heads and that was only one mill in each shop. All the other shops had pulley heads.

derekm
04-13-2009, 04:53 AM
What do you guys do as far as speeds are concerned. Do you try to find a RPM setting and try to leave it there? It is kinda a pain to always keep changing the belts.
I had mine set for 780 rpm, good for face mill but that was to quick for drilling and boring.
Now I have it in the 440 rpm and will try that to see if it works for milling and drilling.

What rpm do you use, or do you keep changing for each job?

I can see a VFD in the future, that would be handy.

One speed is recipe for burned tools and ruined work pieces.. been there done that.

get a VFD and/or mod the machine to make belt changes easier...

Duffy
04-13-2009, 05:20 PM
This may come out as a dumb question, but why do we have to LOCK the idler pulley collar anyway? I faithfully do this every time that I change belt ratios, mostly because it seemed the thing to do. However, on thinking about it, as long as the idler pulley cant dance around, wont the two belts keep it in position? On my drill press this is certainly the case. IF this is correct logic, why not substitute a pair of shoulder bolts to anchor the idler pulley collar; then it would be one less step to change head speeds, (STILL not as good as a VFD-but life is seldom perfect.) Duffy

bruto
04-13-2009, 09:52 PM
This may come out as a dumb question, but why do we have to LOCK the idler pulley collar anyway? I faithfully do this every time that I change belt ratios, mostly because it seemed the thing to do. However, on thinking about it, as long as the idler pulley cant dance around, wont the two belts keep it in position? On my drill press this is certainly the case. IF this is correct logic, why not substitute a pair of shoulder bolts to anchor the idler pulley collar; then it would be one less step to change head speeds, (STILL not as good as a VFD-but life is seldom perfect.) DuffyShoulder bolts should work fine, as long as they're adjusted just right so that the collar can still pivot. You can even just leave the bolts a little loose, and it will work fine, but they'll rattle loose pretty quickly. The springs give you the ability to pivot without having to lock it, but still hold it down snugly so it doesn't rattle.

Big T
04-16-2009, 09:40 AM
My crappy little digicam hates to focus in dim conditions, but here's a picture of the above minor mod to the idler carrier bolts. The springs, of unknown original source, are very stiff:http://img26.imageshack.us/img26/5922/encopressidlermod.jpg (http://img26.imageshack.us/my.php?image=encopressidlermod.jpg)

I did this mod to my mill, and what a difference that makes. Looseing and tighting the bolts took the most time on a belt change.

I had tried to leave them just loose enough to pivot the idler, but they would rattle loose.