Tuesday, 20 February 2018

Dewalt DW738 - replacing the drive wheel and upper wheel

Unfortunately the rubber tyres on this bandsaw are not capable of being replaced and the wear on the upper wheel after nearly 10 years is considerable. Spare parts are still available (2018) for this machine so I decided to buy a new set of wheels to prolong the life of the bandsaw.

The wheels come as a full assembly complete with bearings, new rubber tyres and are a simply bolt off bolt on arrangement. I also bought a new set of rubbing bearings as the old ones had considerable wear.

The procedure to do this is:

  • Open the access door
  • vacuum any residue from previous operations.
  • Remove the table
  • Remove the blade after loosening the upper wheel tensioner

I also removed the upper rack and pinion assembly complete with bearing assembly. While I was at it I removed the lower bearing assembly.

Slacken the motor

Monday, 19 February 2018

Dewalt DW738 - Replacing rear thrust bearings

Over time the rear thrust bearing wear out and can be very easily replaced.
The replacement part is a 608-ZZ-EU (608Z) and has the following characteristics:

  • 22mm outside dia
  • 7mm width
  • 8mm inside diameter
  • double metal shields
  • deep groove ball bearing for thrust and load carrying

Set of new bearings and original bearing shaft

They are very cheap and easily available

To replace the bearings you do have to disassemble various parts of the bandsaw

For the lower bearing

  • Remove the table
  • Loosen the grubscrew holding the lower thrust bearing shaft in place.
  • Gently pull out the shaft. Beware that the grubscrew and nut can fall out so temporarily insert a 10mm drill into the hole and tighten the grubscrew.

For the upper bearing

  • Loosen and remove the nyloc nut and washer holding the rack and pinion adjustment knob in place
  • Remove the rack and pinion assembly complete with mounting shaft
Rack and pinion removed from bandsaw

  • Remove two screws holding the blade guard to the rack and pinion
  • Loosen the grub screw holding the upper bearing shaft in place.
  • Gently pull out the shaft. Beware that the grubscrew and nut can fall out so temporarily insert a 10mm drill into the hole and tighten the grubscrew.

Removing the bearing from the shaft

  • Place the shaft into a suitable 11-12mm inside diameter steel tube and insert both into an engineers vise loosely tighten the vise
  • The bearing should be supported by the tube
  • using a 6mm diameter drill drift or nail punch gently hammer the shaft from the bearing.
  • The shaft will fall into the tube
  • The bearing can be discarded

Replacing the new bearing onto the shaft

  • The new bearing works in both directions so orientation is not a problem
  • insert the stepped head of the shaft into the bearing hole. It will not go in as it is an interference fit.
  • Use a small 6mm socket from a 1/4" square drive socket set
  • Place the narrowest end of the socket onto centre of the bearing. It should be no more than the overall diameter of the inner section of the bearing.
  • Holding the shaft bearing and socket together insert it into the engineers vice and gently tighten the jaws

  • Make sure you have safety glasses on
  • Now gently tighten the jaws ensuring you keep the assembly as square as possible
  • The shaft will go into the bearing until it hits the step on the shaft.


Reassembly for both bearing assemblies is a reverse of respective disassembly

Wednesday, 14 February 2018

Drill Press Upgrade - Part 7 Sliding doors and slide ways

The sliding doors are made from some 1/4" birch plywood cut to size. I also glued some thin hardwood finger rails onto each side. This has the benefit of preventing much wood dust falling through the gap and enables fingers to push or pull the doors open or closed.

The slide ways were made on the router from some hardwood scraps.

They are designed so the slide ways simply are glued to the sides.

As can be seen in this view the doors actually protrude beyond the top of the carcass.
This is by design as the door top rail is a slot in the underside of the storage cabinet top
After the slideways were glued the cubby/carcass and slideway fabrication was sanded and finished with General Finishes Exterior 450.

The cabinet top is the next item to be made.

Tuesday, 13 February 2018

Drill Press Upgrade - Part 6 Assembly of cubby and carcass

The assembly of the cubbies and carcase is very simple. There is no glue used on this and they are simply held together with wood screws. Clearance holes are drilled into the rear panel of the carcass, the cubby is aligned with the edge of the carcass and clamped into place.
Care is taken to ensure the sliding door slots in the bottom plates are aligned and then they are screwed together.

The same process is carried out on the other side.

If you got your measurements right then the column of the drill press will clear the gap created by the back faces of each cubby.