That sounds sensible, too! And there's nothing wrong with being a die-hard bodger - our day will come!How about drilling a 38mm hole and wrapping the bearing with 0.5mm shim stock cut to 116mm long x 5mm wide? Would that not work? It'll certainly be cheaper than a 37mm drill bit. I'm saying all this but I'm no engineer, just a die hard bodger.
37mm hole?
- Thread starter GrahamRounce
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the great waldo
Established Member
Yes use wd40 and go slow, otherwise it will melt and grab. I you go with the router keep the speed low and feed rate high with a bit designed for acrylic and you`ll have to use several passes. I would take it to a laser cutting shop and get them to do it.
Cheers
Andrew
xy mosian
Established Member
Flat bits were mentioned earlier, and I agree drilling from two sides is tricky as there is no registration for the centre on the second side.
However as the bit itself is likely to be filed to the exact required size, then why not file the triangle shaped point to have a parallel side with a tip to start the hole.
6 mm, or possibly 8 mm could work well.
Bodgers unite!
geoff
However as the bit itself is likely to be filed to the exact required size, then why not file the triangle shaped point to have a parallel side with a tip to start the hole.
6 mm, or possibly 8 mm could work well.
Bodgers unite!
geoff
sploo
Somewhat extinguished member
37 * (1 / 25.4) is 1.4566929133858267716535433070866, so if the caliper display is rounding to 4 decimal places then 1.4570 makes sense.
Mate, ignore me. In my man flu state I was talking b******s
Mrs C
Established Member
Had a similar problem recently and bought an old eclipse trepanning tool no 280 which worked a treat. Cromwell sell a similar expandable hole cutter similar to the austr one in a previous post.
This thread has come to the end of its natural life, so thanks to all for your suggestions and advice.
Though the pillar dtill is too weak, this
works pretty well, and this
(where I tried to reduce the cutting area and ground the tips down to "scrape" not cut) might have been ok if I'd been able to do it more accurately.
I'm waiting for some 38mm tube to arrive. Should be fun filing it down to 37mm and grinding "teeth" with a dremel. It had to be mild steel as I couldn't find stainless, but at least the filing etc will be easier, and it should cut perspex, I'm hoping.
Though the pillar dtill is too weak, this
works pretty well, and this
(where I tried to reduce the cutting area and ground the tips down to "scrape" not cut) might have been ok if I'd been able to do it more accurately.
I'm waiting for some 38mm tube to arrive. Should be fun filing it down to 37mm and grinding "teeth" with a dremel. It had to be mild steel as I couldn't find stainless, but at least the filing etc will be easier, and it should cut perspex, I'm hoping.
So anyway, here's the thing:
The hole in perspex is reasonably clean. It's cutting a bit hot, but I guess I can put up with that. It was ½mm dia oversize at first, then a bit more filing and sanding brought it down to only fractionally over. Now to find a 37mm reamer, or more likely a round sanding block. The big, thin bearings seem more sensitive to being too tight than smaller chunkier ones.
The hole in perspex is reasonably clean. It's cutting a bit hot, but I guess I can put up with that. It was ½mm dia oversize at first, then a bit more filing and sanding brought it down to only fractionally over. Now to find a 37mm reamer, or more likely a round sanding block. The big, thin bearings seem more sensitive to being too tight than smaller chunkier ones.
Years back when I used to work with Perspex quite a lot I used paraffin to help with the cut - especially when routing 45 degree chamfers for making boxes.
Ah, ok, thanks. Probably candle wax then. (Just looked at 37mm reamer prices - EEK! No!)
worn thumbs
Established Member
I have seldom seen a simple job drag out for such a long time and at such expense.Is this a necessary aspect of hobby woodworking?Does complication and delay,not to mention the acquisition of more gadgets lead to greater satisfaction?Put another way,if a customer walked into your workshop and sought to get the job done,what would it have cost him/her?A simple routing template would have had the job completed a couple of weeks ago.The learning process can be fascinating but for another generation of novices,a google search may lead to this thread or others like it and all manner of unwarranted assumptions about the best way to approach the job may be made.We need to avoid discouraging newcomers by introducing the notion that solutions to simple challenges have to involve considerable time and equipment to achieve a simple result.The alternative is that nobody tries to progress until they have a workshop full of digital readouts and laser guidance systems.When a sharp pencil and an open mind could lead to discovering a simple way of getting the job done.
A lot of what we do in the workshop, is work out solutions to particular problems and derive satisfaction from this. What the OP has done is produce quite an elegant solution in the form of hole cutter. What snookered him from the start, was the non standard size of the hole and the fact that it has to be an exact fit for the bearing.
I would also have used a template and a router to accomplish the task,( along with a bit of experimentation). In which case, the only difference would be that I had another template to add to my store, rather than another hole cutter.
With all the other posts in this thread, I'm sure that any novice following it should be able to see the bigger picture, and know that it is just one of many different solutions. The route we choose to go down depends on the confidence ( or not) that we have in our own abilities and the tools and equipment that we have to hand. This will undoubtedly have an effect on the solutions we choose.
I would also have used a template and a router to accomplish the task,( along with a bit of experimentation). In which case, the only difference would be that I had another template to add to my store, rather than another hole cutter.
With all the other posts in this thread, I'm sure that any novice following it should be able to see the bigger picture, and know that it is just one of many different solutions. The route we choose to go down depends on the confidence ( or not) that we have in our own abilities and the tools and equipment that we have to hand. This will undoubtedly have an effect on the solutions we choose.
When you google 37mm hole saw one of the first options is a 37 mm starrett hole saw - starrett are my choice of hole-saw and would be my 1st choice simple and fairly cheap at a a tenner . If approach failed then the router/ template option would be next. . No problem accepting there are different ways to achieve the same result but agree they Can just go on and on .. I recently installed a new waste to a basin and the fitting I chose to connect to the soil stack reqd a 57 mm hole so ordered one on line and got it next day , pvc soil pipe not too dissimilar to Perspex can be quite brittle but it worked like a dream - nice and simple and quick..and a really clean cut ..
Yep... Keep it simple.
It's so easy to overthink, and over complicate, things.
It's so easy to overthink, and over complicate, things.
worn thumbs
Established Member
Ever used a normal drill bit to drill acrylic?Pretty much guaranteed to break a chip out of the underside.With a 37mm bit could be a huge chip.I normally back off the cutting edge to give a near vertical face and it works for modest sized holes.Holding a piece to resist the torque applied by a 37mm bit might be an interesting challenge too.
I came back to this thread after a break and remembered what I should have days ago.
If I were doing this job on a milling machine, I'd rough out a hole a little undersize with the biggest drill, holesaw, whatever and then make the precise cut with an adjustable fly cutter.
Turns out you can get 12mm parallel shank fly cutters that will go in a drill press and adjust in various size ranges including what's needed here. They are not a heavy drilling tool but for opening up an existing hole cleanly, that would be my choice.
If I were doing this job on a milling machine, I'd rough out a hole a little undersize with the biggest drill, holesaw, whatever and then make the precise cut with an adjustable fly cutter.
Turns out you can get 12mm parallel shank fly cutters that will go in a drill press and adjust in various size ranges including what's needed here. They are not a heavy drilling tool but for opening up an existing hole cleanly, that would be my choice.
