Delta 20-950 Variable Speed Drill Press - bogging down

[Daniel Shnitka]

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?

[Myk Rian]

Might try some belt dressing on it.

[Larry Komroff]

You might check that the spring loaded pulleys can move easily on their shafts. Might need to clean and lube the shafts of the reeves drive.


Larry

[Myk Rian]

Hope this doesn't mean trouble in the future for you.
From an Amazon comment.....

Delta says: "Unfortunately, since the product you are looking to buy has be [been] discontinued some time ago, the warranty would no longer be in effect." And, "The reason why the model 20-950 was discontinued was related to the variable speed control mechanism and that service parts are not available for this particular model. We are working on improving the quality of this machine for when we do re-introduce this machine. As soon as we can improve the quality to a level that our customers expect from the DELTA brand we will re-introduce." And, "It is in our plans to discuss bringing back the 20-950 Drill Press, but that will most likely not happen for at least a year. We are not sure exactly when it will be available."

[Greg R Bradley]

My recollection is that this drill press was only available from Delta for a few months in 2008 or 2009. There was much anticipation and advance orders and then problems with supply of the drill press and parts. My dealer was the authorized service center and they told me to stay away from it. Some of the issues could have been with the market falling at the time and Delta being sold. That same dealer told me two days ago that the only thing they can get recently from Delta is the Unisaw and 18-900 drill press.

I should note that I have spoken with two people that are very happy with that drill press. One uses it regularly.

On a separate issue, I don't understand the comment about high speed and hole saws. A 5.5" hole saw should probably be run at the slowest speed of that drill press. Are you trying to run large bits at "1800-2500rpm" ????? That is a speed for 1/2" bit in soft wood. Perhaps there is no problem with the drill press. If it has been in the crate for 4 years, it could easily need a new belt.

Warranty is becoming a problem with many items. I continually run into items that are new in the box old inventory that are out of warranty based upon time since manufacture. It isn't tools, but one item I deal with regularly has a 3 year warranty but a maximum of 4 years since date of manufacture.

[phil harold]

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.

There is the problem, 5.5" holesaw on a drill press
I doubt your drill press goes under 100 rpm and can handle that amount of torque
5.5" holesaw should only have speeds of 25-75 rpm for wood and I would have compressed air blowing the chips out and cooling the bit...

[Daniel Shnitka]

Thank you all for the good response and the the advice on drill bit speeds relative to their size and the material being bored.
I will go back to the drill pressand see what can be done.
I will go through one step at a time to evaluate the issue.

The drill press has been in the shop since it was purchased nearly three or more years ago. It has been used occasionalley when time permitted me to get away and work on a project.

I am hoping their is no problem with the drill press and it may need only belt dressing.

[phil harold]

After removing the top cover I could see carbonized rubber belt dust inside the heavey cast iron housing.

Belt dressing is not going to repair the burnt (carbonized) belt
Best bet is replace the belt
Clean the sheaves and hope you did not damage variable speed control mechanism from the excessive abuse