Hole saw problem

ardinn · 17-07-2021 01:26AM #1

I need to put about 300 holes in plywood.

From previous experience from doing similar on painted laminated ply, i gathered its tough on the saws, so bought 4 hole saw 2 different sizes.

I was merrily on my way when the dewalt drill I was using got red hot, started to smoke, I thought it may have been a bit much for it so before any damage was done I took out my electric bosch drill, a beastly thing that's half kango half drill.

Anyway a few holes in she sparks and blows, again its melting hot. (the auld fellas gonna be pis$ed)

What am I doing wrong here, a friend said maybe hole saws should not be used on ply, I would think ply was fairly handy to go through.

If im using this wrong what should I do instead - I need a **** ton of holes and the quote I got for a cnc machine was madness.

Help appreciated

The Continental Op · 17-07-2021 10:02AM

Can you post a picture of the hole saw you are using and indicate what size they are?

If I can find your reply in this mess of a new site I'll see if I can help.

A good quality hole saw should do the job fine. My dewalt drill has no problems.

peter bermingham · 17-07-2021 11:43AM

Forstner drill bits is what your after get a good brand like Famag or Fisher

peter bermingham · 17-07-2021 11:46AM

https://boards.ie/discussion/comment/117623475#Comment_117623475

Forstner Bits | FINE TOOLS

The Continental Op · 17-07-2021 12:13PM

https://boards.ie/discussion/comment/117623475#Comment_117623475

Fine for a few shallow precision holes but imo that would cause the problem as soon as one went a bit blunt you could easily burn a motor out.

I use something like this

https://www.screwfix.ie/p/erbauer-hex-shank-holesaw-arbor-11mm/1779h

with a suitable diameter hole saw

https://www.screwfix.ie/p/erbauer-multi-material-bi-metal-holesaw-70mm/80934

For the better hole saws you have to buy the bits separately.

However the teeth can soon get blunt and extra force to make the hole again could burn the saw out.

ardinn · 17-07-2021 01:07PM

I have those erbaur saws above in 87mm and 114mm - its not that im burning out the saw - im burning out the drills.

A relief hole is something I have seen online last night to let out the sawdust for cleaner rotation, the drills just heat up and die

.G. · 17-07-2021 01:21PM

Spade bits are better for a job like that. I have these, eat through wood. Not sure what's happening with your drills tough unless they have very poor torque.

https://www.amazon.co.uk/Bosch-Professional-2608587009-SELFcut-Speed/dp/B008HRESU6/ref=mp_s_a_1_1_sspa?dchild=1&hvadid=80676698048991&hvbmt=be&hvdev=m&hvqmt=e&keywords=bosch+spade+bit&qid=1626524343&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFZN1o2OUszME5KWVImZW5jcnlwdGVkSWQ9QTAyNTA2OTcxVEEzOUFZQUFPSTJMJmVuY3J5cHRlZEFkSWQ9QTAxNTAzMDZTN0ZaNE1WMzgwOTQmd2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

the_pen_turner · 17-07-2021 01:24PM

what speed is the drill in. going slower can help

what size is the hole saw

get a carbide tipped hole saw if you can. they are a beast to cut through ply. not cheap but well worth it

The Continental Op · 17-07-2021 02:42PM

https://boards.ie/discussion/comment/117623822#Comment_117623822

87mm and 114mm

apparently. In my old fashioned imperial brain that 4 1/2 inch holes, you'd want a bit of a beast of a drill to do 300 (or even 150) of them.

foxy farmer · 17-07-2021 02:47PM

Teeth are getting clogged. Frequent removal of the holesaw from each hole cleaning of cutting edge with a wire brush is my suggestion.

the_pen_turner · 17-07-2021 02:55PM

https://boards.ie/discussion/comment/117624108#Comment_117624108

missd that some how.

114mm would be a bit hard on the drill. thats why i bought the dewalt stud and joist drill. its a beast.

OP maybe you should look at a router and template method.

policarp · 20-07-2021 01:23AM

https://boards.ie/discussion/2058199246/hole-saw-problem

Drill a hole or two just inside or outside your required diameter.

This will let the sawdust escape.

20-07-2021 08:13AM

You are simply expecting too much from your Dewalt. A Hilti or Makita drill would not have this issue as they are designed for professionals. The Dewalt is aimed far more at the DIY market. That is not to say that Dewalt are not good, in fact in most cases they are up to the job, but 300 holes is a bridge too far. This is especially the case when you consider the additional loading that the hole saw puts in the shaft of the drill due to the “law of the lever”.

Also electrical motors need to be cooled. This in this case it is achieved by mounting a fan on the motor shaft. The increased mechanical load slows the drill down, this means the fan is rotating slower which in turn reduces the cooling effect. Additionally the reduced speed results in a higher current being drawn from the supply. The square of the current is directly proportional to the heat generated.

Hole saw problem

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