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

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.



Monday 12 February 2018

Dewalt DW738 Bandsaw Review

I've had this bandsaw now for nearly 10 years and thought it's about time to review it.
Essentially this is a 13" bandsaw (nominally 12") and has a resaw capacity of 155 mm or 6".
The version I have is a 2 speed saw with the speed changed by moving the drive belt onto different pulleys. When supplied from the factory it is in low speed mode and I didn't move that setting until early on in 2014. Then it was found that it ran much too fast for the type of work I use it for. So I moved it back to the slow speed. It is more trouble than it is worth to change it.
Assembled Dewalt DW738 Bandsaw

There is another saw with a continuously adjustable speed setting and it is designated the DW739. That saw is not reviewed here but probably is similar in specification and operation.

Unlike a lot of good Dewalt equipment it should be a different colour. Like Bosch DIY green against Pro blue. Dewalt DIY stuff needs to be brown instead of corporate professional yellow. It is definitely hobby DIY level but has served me well for the last 10 years.

Reworking the clamp wall

For a number of years I have been building up my clamp wall. The wall is made from concrete blocks and I have simply screwed the shop made clamp racks to it. Over time the wall has got fuller and fuller to which point I needed a change. The white paint on the blocks had become lightly coated with wood dust, as happens in a wood shop, so I had the idea of getting 3 - 4' x 8' sheets of 18mm (3/4") OSB to line the walls.
Organised and fairly tidy

But could do with improvement

A delivery of OSB3 was made a few days ago and I cut them to the right length with my tracksaw. Then it was a simple matter of standing each of them upright and screwing them to the wall using masonry screws. Any load hung on the boards would be partially transferred to the concrete floor and any turning moment would be compensated for by the screws.

A few hours later and the wall was lined with OSB. I then set to work on the wiring. There is an existing double socket for the computer and an existing fused switched outlet for the radiant panel heater. I routed the wiring to suit the required position of the devices.

Wednesday 7 February 2018

Drill Press Upgrade - Part 5 the Cubby Units

The cubby units give the chance for me to store little used items which are still local to the drill press. Occasionally used sanding drums spring to mind for usage here.

The cubbies themselves again are open boxes made from 18mm (3/4") birch plywood. They are made in a similar way to the storage carcass using glued and screwed construction. Nothing major or difficult to do here.

2 storage cubbies like this are required
I put a shelf in the centre of the vertical span and the back is made from 12mm (1/2") birch ply.
There are also glued in shelf rails to minimise things falling out should a door be open and you decide to move the storage unit.

Cubby without its shelf - this will be glued in after assembly to the storage unit



Monday 5 February 2018

Drill Press Upgrade - Part 4 the Storage Unit Carcase

The carcase is a very simply construction and is basically and open box. This is entirely made from birch plywood 18mm (3/4" nominal) thickness.
Carcase design
Cutting the plywood is best performed with a tracksaw but can be done with a conventional circular saw/edge guide or, if you are feeling strong, the tablesaw.
Since getting my Bosch tracksaw I have long given up on cutting sheet goods with a tablesaw or any other tool for that matter. The tracksaw is the perfect tool for the job and you don't end up with a hernia or a chiropractors bill!

Each of the components was cut to size. I then used the router table with a rabbeting bit to cut the various rebates (rabbets US). My European tablesaw does not have an arbor that will take a dado stack but I know a few of my North American friends use them.

Once the rebates were cut the rear and side plates were drilled with a 75mm (3") pitch of pocket holes around the perimeter. As already mentioned the addition of mechanical fasteners (pocket screws) in addition to glue and rabbets makes for an immensely strong joint.
The components were glued and screwed together.