Thread: drill press pulley problem?

Hi surfmat, sounds as thoughyou have a 12 or 16 speed drill press, which means that the centre pulley is intended to move. Firstly to be able to change speeds and secondly itallows you to have the correct tension on both belt so that the speed remains constant without any slippage caused by incorrect belt tension.
Hope this helps you. Actually could you take some photos of the belt system of your drill press which well show me what is going on in the arrangement of the belt/pulley system.
Cheers Alby

cheers Alby, I think its 16 speeds, not at home at the moment but found this image that is almost identical (apart from the ally pulleys, mine are cast)...I'll take some shots when I get home and upload. cheers
Matt

Matt,

Yes the centre pully show swing depending on the postion of the belts to apply tension. Check the pully above the quill to make sure the nut securing has not come loose. This happened to me. It may be a left hand thread and thats why.

cheers bleeder...yes, the arm should be free to move, I guess its onto WD-40 and the hammer to get it moving I guess.
I think when I left it in my fathers shed while I went around the country a few years ago it must have just rusted in place and as I never adjust the speeds I never really took any notice. I think this could be one of the causes of the vibration. the other is certainly the motor. and probably an overtensioning of the belts for an extended period.. I think I might need to raise the pulley on the motor as well to line it up properly with the others. ....I just want to get rid of the motor vibration now....
cheers
matt

Matt,

WD40 is a really hit and miss affair with me. I use Inox as I have found it penetrates better. May have to do it over a few days. Hitting with a hammer would be a very last resort. It may pay to look a removing it as it is only a sleeve that holds the shaft in.

Getting the motor aligned with the pulley assembly is a good idea.

sounds like a good idea, I think that you're right about the inox...I'll give it a go
cheers
Matt

If you have not changed speeds or released belt tension for a number of years, the belts will have developed a memory and will want to hold the shape that they have been stretched into. This will cause slippage and a lot of vibration as they forced to run on the pulleys. I would be replacing them with decent new ones.

The mounting arm for the centre pulley should be free to swivel on its pivot to balance belt tension, and also able to lift freely to allow belts to align naturally when tensioned. Once you get the old belts off, you may be able to free the pivot arm and pin by spraying, tapping for and aft and lifting with a prybar. Once you can free the pivot pin from the head casting, you will probably have to derust and clean the pin and hole in the head casting. I would assemble with a small amount of copper anti sieze grease to prevent further freezing.

good advice, I think I'll replace the belts also, I've heard that people are talking up the link belts as well ...I think I'll just go for a V belt for the moment and see if its better before shelling out the big bucks.
cheers

I agree about changing the belts, 20 year old belts are almost certainly stiff and "lumpy".
Have heard good reports about the link belts. Will be getting one for my lathe where I can't easily replace it without unbolting the motor (no clearance around the pulley)
Would like to hear how you go with this, and suggest trying the new belt alone, and save the hammer for later

I have been researching rust penetrant on internet recently and one of the most mentioned stuff was a equal mix of Auto Transmission Fluid and acetone. A mag did a test and it came out far ahead of others. The acetone has a very low surface tension so it gets into the smallest gaps taking the oil with it and then evaporates leaving the oil behind. I am currently trying it myself.

My drill press also rattles a lot but I think it is caused by the movement of the middle pulley. It is not in line with the others and is loose in the casting. I plan on a modification with the addition of some bearings.

Dean

thanks guys,
i've soaked it in penetrant and still no joy...even tapping it with the hammer will move it around on its axis but not break the bind...added more and will have another crack tomorrow..... starting to worry about shearing it off with all the jigging around.....

Hi All,

I 've had this same problem with my Hitachi D/P since new.

Things that i've tried

1. Insulated the motor mounting from the D/P with 6mm thick rubber insertion.

2. Re-alinged the 3 pulleys horizontally.

3. Re-alinged the centre floating pulley vertically. The dog leg was not welded in the correct position.

None of the above fixes have improved the situation.

My current thinking is that the problem is in the Spindle / Bearings / Quill, which i've not dismantled as yet.

I,m afraid i don,t have an answer to the problem at this stage, but every time i use the D/P it certainly gets me thinking again.


Regards,

Alan

One thing worth trying might be to isolate each potential imbalance: take the motor pulley right off and run the motor in its own. If no vibration, reinstall pulley but not belt. If still no vibration, install belt to only centre pulley (and hold it tight manually). If still no vibration, the quill or its pulley is the cause. Any vibrations in this sequence will tell you what's causing the vibration. The you can see if you can at least do a static balance of the offending component by drilling holes in the heavy side or grind bits off progressively until balanced - or bolt things to the light side of course.
Joe

Could also be a problem with uneven pulley surfaces as opposed to unbalanced. In regards to the quill that was one of the first things I looked at because my chuck and shaft move until the drill touches the work then it turns true (sort of). I found the vertical position of the quill pulley was held by a tiny bit of plastic disk with a grub screw against it. This disk was not even the right diameter. It has now been replaced with a more precise steel disk. I think it was sandwiched between the two pulley bearings.

My next move will be to make a new centre pulley pivot system. Currently it is a crank that drops into a hole drilled into the top of the casting. The hole is bigger than the crank shaft and the crank is not square. I plan on mounting a vertical shaft and making a new crank which rotates on this shaft via bearings.

Dean