Daniel Shnitka
02-21-2013, 3:43 PM
The problem with the Delta 20-950 variable speed began with the cutting of some oak 8/4 with a 5 and 1/2 inch hole saw. The hole saw would start to cut smoothly then start to slow down as it began to bite into the wood. Next thing that would happen is the hole saw would bog down and nearly stop rotating. Just as it would begin to slow down I would immediately back of drilling and allow the the drill to come up to speed and then slowly re-enter the work piece with the hole saw drill back up to speed.
I eventually completed the task of cutting the oak with the the hole saw using the drill press and this took a very long time.
When I went to drill a one inch hole in 1/2 inch thick rosewood using a Forstner drill bit the drill press bogged down again when it was barely into the wood 1/32 of an inch .
This morning a test cut on a alder resulted in the same issue. After removing the top cover I could see carbonized rubber belt dust inside the heavey cast iron housing. I observed the the front variable speed pulley widen on its own under load while trying to drill a one inch hole in Alder at moderately high speed. As I increased the speed to the maximum of 2500 RPM the belt connecting the variable speed pulleys was barely turning the front pulley. The rear pulley was spinning away at a constant speed as it was driven by the electric motor. The rear belt from the electric motor pulley to the variable speed drive pulley at the rear was snug and working fine.
At lower speeds the the belt slipped considerably less and at the lowest speed virtually eliminated all slippage and the Forstner bit cut through the test piece of Alder.
I concluded there are three possible problems with the drill press:
1. The connecting belt between the variable speed pulleys is slipping because the friction edge of the belt is not effective because it has become worn smooth. The belt is new with the drill press. The drill press was bought new and approximately 6-8 hours of use.
2. The belt is slipping because the varible speed pulley is opening wider under load because there is not ample tension created by the spring on the front pulley.
3. The higher speeds 1800 to 2500 are not applicable for working with hole saws or wood drill bits when any amount of resistance is exspected. I f this is the case then it is clearly a short coming of the Delta drill press.
What corrective action do I need to take? Has anyone had experience with this issue and what were you able too do to correct it?
I eventually completed the task of cutting the oak with the the hole saw using the drill press and this took a very long time.
When I went to drill a one inch hole in 1/2 inch thick rosewood using a Forstner drill bit the drill press bogged down again when it was barely into the wood 1/32 of an inch .
This morning a test cut on a alder resulted in the same issue. After removing the top cover I could see carbonized rubber belt dust inside the heavey cast iron housing. I observed the the front variable speed pulley widen on its own under load while trying to drill a one inch hole in Alder at moderately high speed. As I increased the speed to the maximum of 2500 RPM the belt connecting the variable speed pulleys was barely turning the front pulley. The rear pulley was spinning away at a constant speed as it was driven by the electric motor. The rear belt from the electric motor pulley to the variable speed drive pulley at the rear was snug and working fine.
At lower speeds the the belt slipped considerably less and at the lowest speed virtually eliminated all slippage and the Forstner bit cut through the test piece of Alder.
I concluded there are three possible problems with the drill press:
1. The connecting belt between the variable speed pulleys is slipping because the friction edge of the belt is not effective because it has become worn smooth. The belt is new with the drill press. The drill press was bought new and approximately 6-8 hours of use.
2. The belt is slipping because the varible speed pulley is opening wider under load because there is not ample tension created by the spring on the front pulley.
3. The higher speeds 1800 to 2500 are not applicable for working with hole saws or wood drill bits when any amount of resistance is exspected. I f this is the case then it is clearly a short coming of the Delta drill press.
What corrective action do I need to take? Has anyone had experience with this issue and what were you able too do to correct it?